Purification of Laboratory Chemicals: Part 2 Inorganic Chemicals, Catalysts, Biochemicals, Physiologically Active Chemicals, Nanomaterials

By W.L.F. Armarego

Purification of Laboratory Chemicals: Part Two, Inorganic Chemicals, Catalysts, Biochemicals, Physiologically Active Chemicals, Nanomaterials, Ninth Edition describes contemporary methods for the purification of chemical compounds. The work includes tabulated methods taken from literature for purifying thousands of individual commercially available chemical substances. To help in applying this information, the more common processes currently used for purification in chemical laboratories and new methods are discussed. For dealing with substances not separately listed, another chapter is included, setting out the usual methods for purifying specific classes of compounds.

Laboratory workers, whether carrying out research or routine work, will invariably need to consult this book. Apart from the procedures described, the large amount of physical data about listed chemicals is essential. This fully updated, revised and expanded new edition includes the purification of many new substances that have been available commercially since 2017, along with previously available substances which have found new applications.

• Features empirical formulae and formula weights for every entry
• References all important applications of each substance
• Includes updated CAS registry numbers
• Covers the latest commercial chemical products, including pharmaceutical chemicals and safety/hazard materials
• Provides expanded coverage of laboratory/work practices and purification methods

• Language: English
• Publisher: Elsevier Science
• Release date: Aug 27, 2022
• ISBN: 9780323958288

W.L.F. Armarego

Wilfred L. F. Armarego graduated BSc (Hons) in 1953 and PhD from the University of London in 1956 and came to Australia in that year. After two years at the Central Research Laboratories (ICIANZ) in Melbourne, where he worked on plant growth substances, and one year on potentially carcinogenic polycyclic aromatic hydrocarbons at the University of Melbourne as Senior Demonstrator in Organic Chemistry, he joined the Department of Medical Chemistry as a Research Fellow in 1960. He became a Fellow in 1963 and was awarded a DSc degree (London) in 1968. He was promoted to Senior Fellow in 1967 and began research work on the biochemistry and molecular biology of pteridine-requiring enzymes related to the inherited metabolic disease phenylketonuria and its variants. He was head of the Protein Biochemistry Group and Pteridine Biochemistry Laboratory until his retirement in 1996. He is now a visiting fellow at the John Curtin School of Medical Research, and member of the editorial boards of ‘Medicinal Research Reviews’ and ‘Pteridines’ journals.

Book preview

9780323958288_FC

Purification of Laboratory Chemicals

PART 2

Ninth Edition

Wilfred L. F. Armarego

Department of Genome Sciences and Cancer, The John Curtin School of Medical Research, ANU College of Medicine, Biology, and Environment, The Australian National University, Canberra, A.C.T., AUSTRALIA

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AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO

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Table of Contents

Cover image

Title page

Dedication

Copyright

Preface to the Ninth Edition

How This Book Should Be Used

DOIs, PMIDs, ISBNs and ISSNs

Video Presentations

About the Author

Introduction

Chapter 1A: Inorganic Compounds

Abstract

Introduction

Chapter 1B: Metal-Organic Compounds

Chapter 1C: Miscellaneous As, B, P, Si, S, Se and Te Containing Compounds

Chapter 2: Catalysts

Abstract

Introduction

Catalysts—Part 1

Homogeneous Metal Catalysts

Organocatalysis

Phase Transfer Catalysts

Imidazolinium Ionic Liquid Crystal Catalysts

Catalysts—Part 2

Chiral Auxiliaries

Lewis and Brønsted/Lowry Acids and Bases (definitons)

Bibliography

Books and Reviews

Chapter 3: Purification Of Biochemicals

Abstract

Introduction

3A. Amino Acids and Peptides

3B. Proteins, Enzymes, DNA and RNA

3C. Carbohydrates

3D. Carotenoids

Bibliography

3E Steroids

Chapter 4: Physiologically Active Compounds

Abstract

Chapter 5: Nanomaterials

Abstract

Introduction

Identification and Measurement of Nanomaterials

Fullerenes and Related Substances

Fullerenes

Functionalised fullerenes

Carbon Nanotubes (CNTs) and Related Materials

Preparation of CNTs (NTs)

Purification of CNTs (NTs)

Preparation and Purification of Fullerene Pipes (TUBES)

Solubilisation of CNTs

Carbon Nanotubes (CNTs)

Functionalised CNTs

Graphene Materials

Self Assembled Monolayers (SAMs)

Diamond Nanomaterials

Solvent Resistant Nano Filters (SRNF)

Nano Metals and Metal Derivatives

Some Organic and Metal-Organic Nanomaterials

Nano Chips

Safety Issues

Bibliography

General Index

CAS Registry Numbers Index

Dedication

A substantial number of inorganic and organic chemicals have some sort of physiological activity towards living organisms, be it microorganisms, animals, humans or plants. That should be foremost in mind when working with chemical substances. Although many may not be of biological origin, they could interfere with biological functions. Biological or biochemical substances, on the other hand, are by definition of biological origin and therefore have some biological function and are in themselves physiologically active in one way or another. I am most fortunate in having a daughter, Dr Sarah Helen Armarego, who is currently a consultant anaesthetist and has many years of knowledge and practical experience in the daily handling of physiologically active chemicals and drugs. She is well aware of how these can affect human metabolism either directly from her work or from having acquired the information from known sources in the medical literature. She has always been interested in my chemical work and ready to advise me on how such substances may act on living cells or tissues. Although a chapter (4) is devoted to physiologically active compounds, a large number of substances in other chapters, as well as compounds included in Part 1, also have biological activity. Brief statements of their activities have been added at the end of the respective entries and my daughter’s advice here was invaluable. Many drugs in Chapter 4 were included at her suggestion. In addition to this she wanted me to keep her informed of my progress with writing, and was quite prepared to complete Part 2 if, for some reason, I was unable to do so. Luckily this did not eventuate and I was able to complete my writing on time. For all her input and for her loving attention to my work over the years, I dedicate Part 2 of the 9th edition to her with all my love.

W.L.F. Armarego

Copyright

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This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

ISBN: 978-0-323-90968-6

For information on all Butterworth-Heinemann publications visit our website at https://www.elsevier.com/

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Publisher: Susan Dennis

Acquisition Editor: Anita Koch

Editorial Project Manager: Emerald Li

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Preface to the Ninth Edition

I was aware that the 8th edition of Purification of Laboratory Chemicals was highly cited from the reports that I received in my daily emails from ResearchGate as well as from Science Direct and were confirmed by the high sales numbers. This edition was submitted in September 2016, and during the intervening five years a large number of new and useful chemical substances and reagents have appeared in catalogues, and improvements in identification procedures such as new NMR spectroscopy at > 1 GigaHz fields have been made. A considerable number of websites in which visual presentations of purification procedures as well as basic scientific principles have appeared online and should be very useful complements for statements made in the book. Dr Anita Koch, Acquisition Editor of Elsevier’s ‘Chemical and Process Engineering Books’ had approached me to see if I would undertake a revision and an updated edition to address these issues. She proposed an increase in size of about 100 pages for a 9 th edition which I agreed was reasonable. However, an extra 100 pages will result in a book that would contain more than 1300 pages and could not be produced as a single volume. She then suggested that the work could be divided into two parts as stand-alone volumes. All my proposals for this possibility were accepted for the 9th edition.

The two parts are named Purification of Laboratory Chemicals Part 1 and Purification of Laboratory Chemicals Part 2. Each has a Preface, Dedication, Table of Contents, a large body of Text, a General Appendix and a CAS (American Chemical Abstracts Service) Registry Numbers Appendix. The body of Part 1 consists of three chapters. Chapter 1 contains Physical Methods used in Purification, Chapter 2 discusses Chemical Methods used in Purification and Chapter 3 presents thousands of compounds on Purification of Organic Compounds (3A Aliphatic compounds, 3B Alicyclic compounds, 3C Aromatic compounds and 3D Heterocyclic compounds). Part 2 consists of five chapters. After a brief introduction, the purification and properties of thousands of substances are presented in Chapter 1 Purification of Inorganic compounds (1A Inorganic compounds, 1B Metalorganic compounds, 1C Miscellaneous As, B, P, S, Se, Si and Te containing compounds); Chapter 2 Catalysts— Part 1, and Catalysts—Part 2; Chapter 3 Purification of Biochemicals (Introduction, 3A Amino acids and Peptides, 3B Proteins, Enzymes, DNA and RNA, 3C Carbohydrates, 4D Carotenoids and 5E Steroids); Chapter 4 Physiologically Active Compounds and Chapter 5 Nanomaterials. The two parts will also be incorporated into one e-Book which can be placed on the desktop of a laptop computer and used in an office, laboratory setting or at home, for ready access of data and direct online connection to the original literature.

Like in the 8th and previous editions, the original aims have been adhered to, i.e. to provide procedures for the purification of commercially available compounds, their physical properties, and in some cases their chemical syntheses as these provide information regarding impurities. Original literature references for individual entries are provided, together with their DOI (digital object identifiers), and/or PMID (PubMed ID’s), and the ISBN or ISSN identifications for books. Sections of the books and many entries have been updated, old but useful entries that were omitted previously have been inserted as well as new compounds that have recently become commercially available. Wherever possible, known applications and biological properties have been briefly inserted within the entries. Emphasis on personal and laboratory safety is of paramount importance when handling chemical substances, and these have been highlighted throughout the books. Any cross referencing between the two Parts can be done via the General Index and the CAS Registry Numbers Index which identify all chemical substances. Each Part has its respective General Index and its respective CASRegistry Numbers Index. These CAS numbers will inform the reader of the page number where a particular substance will be found, but if the number is absent in the CASRN Indexes then the corresponding substance is not mentioned in these books.

The large variety and number of examples of purification procedures described in this book should make it possible for an experienced laboratory worker to devise appropriate methods for the purification of any number of substances not included in these books.

I should like to acknowledgements the following:

I am gratefully indebted to Professor David Tremethick (Department of Genome Sciences and Cancer, John Curtin School of Medical Research, ANU) for his continued encouragement over the years and for supporting my Visiting Fellowships in his Department.

I also thank Honorary Professor Martin Banwell FAA, AO, Hon. DSc, FRACI, FRSC, FRSNZ, Research School of Chemistry, ANU, and additionally Director of the Institute for Advanced and Applied Chemical Synthesis (IAACS), Jinan University, China, for his continued support over the years, and particularly when I needed it most.

I am indebted to Professor Hiroyasu Taguchi (Department of Medical Chemistry, Molecular Neuroscience Research Centre, Shiga University of Medical Science, Japan) for his encouragement and his support for this and previous editions of this book, and particularly for allowing me to include data from his work on curcumin and its derivatives, and their use in the diagnostics of Alzheimer’s disease.

To Professor Maria Schwemlein, (Department of Chemistry, Winston-Salem University, NC, USA) for making me aware that the internet is now abound with video presentations, available free of charge, on a large variety of topics from simple chemical procedures such as crystallisation, distillation, chromatography, syntheses, aromaticity etc, and safety issues to the mode of action of plasminogen, ACE inhibitors etc, and to the applications of nanomaterials. -Throughout the two parts every effort has been made to draw the reader’s attention to online video presentations and how to access them.

The continued help from Joe Papa BS MS (EXAXOL in Clearwater, Florida, USA) with the preparation and purification of several inorganic compounds, and trace metal analyses of a large number of commercially available inorganic compounds included in this work and earlier editions, is much appreciated and gratefully acknowledged. I wish to thank my wife Dr Pauline M. Armarego for her continued help (see Dedication in Part 1), my daughter Dr Sarah H. Armarego MB.BS, FANZCA, (see Dedication in Part 2) for providing and discussing with me information on many physiologically active substances and their medical aspects, and for putting the final touches to the two manuscripts.

Finally, I thank the ANU library and its staff, both on campus and at the ANU Print Repository, particularly Ms S.P. Broderick, for their prompt and unfailing assistance.

W.L.F. Armarego December 2021

How This Book Should Be Used

Substances have been entered in their respective chapters, sections and subsections. In these sections, compounds are listed in alphabetical order according to their more commonly used names. Because compounds can be named in various ways, some alternate names, as well as the commonly used abbreviations and commercial synonyms, have been included in brackets after their entries. Sometimes it may be difficult to find a particular substance; in which case it is advisable to obtain the page number of the entry from its Chemical Abstracts Service Registry Number in the ‘CASRNs Index’ at the end of the book. This index is the gateway t o the book. CASRNs of substances are readily obtained from ‘SciFinder’, or better, from any commercial catalogue that sells these compounds, as almost all of these have CASRNs inserted after the names of their products. Some substances that could be formally included in more than one section of the book are entered in the preferred section but are cross-referenced by inserting ‘see CASRN’ or just the ‘CASRN’. Thus the cross-reference is its CASRN. The CASRNs Index provides the page numbers in bold/italic type. If the CASRN of a desired substance is not in the CASRN Index, or its full or abbreviated name is not in the General Index, then it will not be present in this book. CASRNs are unique for each substance and are internally consistent. They are set up according to a specific formula. Refer to the first page of the CASRNs Index to calculate the formula in order to check whether or not the number is a valid CAS number.

DOIs, PMIDs, ISBNs and ISSNs

The number of references to the original literature has been increased considerably in this edition. Every effort has been made to locate the respective DOIs (Digital Object Identifiers) and these have been inserted after each literature reference. More than 95% of DOIs have been found. If a publication has not yet been allocated a number, is too old, or has altered its name and not been allocated a number, no DOI is recorded. Occasionally in such cases, but not always, it may be possible to download the publication by inserting the full reference title into an internet server, e.g. ‘Google Scholar’. If the letters DOI: before the reference characters are not successful in providing the original publication by using a particular browser (server), then try the same characters with ‘doi:’ before them or the web identification followed by the DOI: numbers. Where this is not possible, a copy of the publication will have to be obtained from a national or international library. In some publications, particularly with medical publications, PMID numbers (see Preface) are the best alternative means to DOIs for accessing the publication directly from the internet. For books and serials the ISBN and ISSN numbers respectively should be used to access information about them from a server. The usefulness of these numbers is that anyone can access the original literature directly from a laptop or other computer that is connected to the internet from any situation viz a laboratory, an office, a library or from home.

Video Presentations

A little over a decade ago, more and more websites have appeared in which experienced scientists and educators have produced short films of 20-30 minutes which describe not only laboratory procedures but also display the foundations of basic scientific principles and concepts. Most of them are well prepared and are adapted for a wide variety of audiences and levels of scientific knowledge. A small number are not particularly well done or clear enough and these inspired better teachers to make clearer and more readily understood productions. Thus, websites displaying several visual presentations of the same subjects have appeared. Almost all displays can be viewed free of charge, but because some experimental displays involve running costs, such as purchase of liquid or solid chemicals or equipment, the displayers invariably ask for small voluntary donations. Also, some presenters inform viewers that, at a price, they are willing to prepare a visual presentation of a subject for their own requirements. In 2006 Moshe Pritzher in Cambridge MA, USA established the Journal of Visualized Experiments (JoVE) [PMID: 25611443; DOI: 10.1080/02763869.2015.986795]. It is a monthly periodical which covers research methods and experimental techniques in the physical and life sciences. In 2014 it had an impact factor of 1.325. See also: Neal Moawad, Introducing JoVE Science Education jove.com, 2013. JoVE’s new Science Education Collection have launched two collections aimed at coaching scientists on basic techniques, after 21-05-2018; see also Jamie Holmes’ How Methods Videos Are Making Science Smarter The New Yorker August 28, 2015. Quite simply, enter the desired subject, e.g. fractional distillation or GC-MS-MS, into your web browser and look for entries which state that they include a video presentation. Alternatively just type into the browser box and several video presentations will appear. Just click on the one you want to view and go from there. It should be interesting to look up the videos say by Professor Robert B. Woodward (Nobel Laureate 1965) of Harvard University, USA, by typing in <Videos of Robert Burns Woodward Lectures at Harvard on synthesis.> and particularly his lectures on vitamin Bi2.or other natural products that he synthesised in his lifetime. One can also type into the browser box . See also the role of visual representations in scientific practices, international Journal of STEM Education, 1(1) 12 2015> and <https://journals.sagepub.com/doi/10.1177/0273475306291466>. Reminders that video presentations are available on line have been made throughout this book.

SAFETY DISCLAIMER: We take no responsibility for any harmful and/or unsuccessful attempts that occur when repeating experiments that are viewed online. See also and online.

About the Author

Wilfred L. F. Armarego was a British Subject born in Alexandria, Egypt, on 23 April 1931, and was educated at British Boys’ School (Alexandria), where he matriculated externally (University of London). In 1949 he enrolled as an external free auditor at Farouk 1st University (later, University of Alexandria). He attended some lectures and all practical classes while studying mostly at home. In June 1951 he obtained the Intermediate BSc qualification (external, University of London) in Chemistry, Physics and Biology, and two years later in June 1953 he succeeded in the University of London External BSc Special Honours degree in Chemistry. In September 1953 he left Egypt for London. He began his research training in stereochemistry at Bedford College (University of London) in November 1953 under the tutelage of Professor E. E. Turner FRS, and subsequently submitted a PhD thesis in December 1955. In September 1956 he went to Melbourne, Australia, and was appointed Research Officer at the new ICI.ANZ Central Research Laboratories where he worked on plant growth substances for 2 years. This was followed by a year as Senior Demonstrator in Organic Chemistry at the University of Melbourne. He was appointed Research Fellow in the Department of Medical Chemistry, John Curtin School of Medical Research (JCSMR), Australian National University in Canberra, in January 1960 to work on the syntheses and physico-chemical properties of heterocyclic compounds related to drugs. He was promoted to Fellow in July 1963 and Senior Fellow in July 1967. He supervised research groups which included MSc and PhD students, Research and Postdoctoral Fellows. He was awarded a DSc degree of the University of London for his work in heterocyclic chemistry at the early age of 35 years. In 1972 he transferred to the Department of Biochemistry and Molecular Biology (JCSMR) and changed his research field to studies of pteridine requiring enzymes associated with a variety of inborn errors of metabolism in children. This involved work on enzyme purification, cloning, mutation, gene expression, kinetics and enzyme mechanisms. He found that the kinetics of the affected enzymes corresponded nicely with the severity of the diseases. He worked in the JCSMR for 36 years until his retirement in December 1996.

In 1969 he became a naturalised Australian. He has been a Visiting Fellow in the JCSMR since his retirement. He has written four books,¹-⁴ in addition to over 140 research publications. He was awarded FRSC (Fellow of the Royal Society of Chemistry, FRIC 1963), C.Chem (Chartered Chemist), FRACI (Fellow of the Royal Australian Chemical Institute, 1972), A.D. Olle Prize (1968) and Worldwide WHO’sWHO 2014 Professional of the Year, representing Medical Research. In the 2019 new year honours he was awarded Member of the Order of Australia, AM, for ‘Significant Contributions to Biochemistry and Molecular Biology’.

1.W.L.F. Armarego, Fused Pyrimidines Part 1 - Quinazolines 1967, 537pp (Wiley-Interscience: NY).

2.W.L.F. Armarego, Stereochemistry of Heterocyclic Compounds, Part 1. Nitrogen Heterocycles 1977, 433pp (Wiley-Interscience: NY).

3.W.L.F. Armarego, Stereochemistry of Heterocyclic Compounds, Part 2. Mixed O, N, and S, and Phosphorus Heterocycles 1977, 494pp (Wiley-Interscience: NY).

4.W.L.F. Armarego, alone or with D.D. Perrin, D.R. Perrin, or C.L.L. Chai, Purification of Laboratory Chemicals 1st Edn 1966, 362 pp (Pergamon Press: Oxford); 2nd Edn 1980, 568 pp (Pergamon Press, Oxford); 3rd Edn 1988, 391 pp (Pergamon Press, Oxford); 4th Edn 1996, 512 pp (Butterworth-Heinemann: Oxford), 5th Edn 2003, 609 pp (Elsevier, B -H: Oxford); 5th Edn Chinese translation 2005, pp 661 (Elsevier); 6th Edn (enlarged) 2009, 743 pp (Elsevier, B-H: Oxford), 7th Edn (greatly enlarged) 2013, 1002 pp (Elsevier B-H, Oxford), 8th Edn (enlarged) 2017, 1200 pp (Elsevier B-H, Oxford); and including this 9th edition, 2022, Part 1 640 pp and Part 2 pp 671.

Email: < [e-mail] > or < [e-mail] >.

Introduction

Purification of Laboratory Chemicals 9 th edition, Part 2 continues from where Part 1 ends. These parts follow each other and substances have been cross-referenced through their respective CAS registry numbers Index entries. Part 2 has five chapters. Chapter 1 consists of Purification of Inorganic Compounds which is subdivided into Chapter 1A Inorganic Compounds, Chapter 1B Metal-Organic Compounds, and Chapter 1C Miscellaneous As, B, P, Si, S, Se and Te Containing Compounds. Chapter 2 consists of Purification of Catalysts and is subdivided into Catalysts - Part 1 which includes catalytic substances, and Catalysis — Part 2 which includes ligands or compounds used to make catalysts. Chapter 3 consists of Purification of Biochemicals starting with an Introduction of general purification of biochemical substances followed by Chapter 3A Amino Acids and Peptides, Chapter 3B Proteins, Enzymes, DNA and RNA, Chapter 3C Carbohydrates, Chapter 3D Carotenoids, and Chapter 3E Steroids. Lipids, terpenes and alkaloids are not allocated subsections because they are included in other chapters and/or sub-chapters, but particularly in Chapter 3A Aliphatic Compounds, Chapter 3B Alicyclic Compounds and Chapter 4A Heterocyclic Chemistry respectively of Purification of Laboratory Chemicals 9 h edition Part 1. Chapter 4 comprises of Physiologically Active Compounds and lastly Chapter 5 contains Nanomaterials and Nanotechnology.

The general principles, techniques and methods of purification in Chapters 1 and 2 of Purification of Laboratory Chemicals Part 1 are applicable to Part 2. Most inorganic and organic liquids and a number of solids can readily be purified by fractional distillation, usually at atmospheric pressure. Sometimes, particularly with sensitive or high boiling liquids, or when in doubt about stability, distillation or fractionation under as low a pressure as possible should be carried out. The purification of organic compounds that contain metals such as salts, inorganic compounds and metal-organic compounds are to be found in Chapter 1. Here also where boiling points are given, purification by distillation is another means of removing impurities. Substances are listed alphabetically according to their commonly used names in each section, usually with some criteria of purity, giving brief details of how they can be purified. In several cases, some details of the chemical syntheses of substances are provided which include final purifications that can be adopted or adapted. Also noted are the empirical formulae, the formula weights (to the first decimal place), the melting points and/or boiling points together with the respective densities and refractive indexes for liquids, and specific optical rotations for chiral compounds. All temperatures are in degrees centigrade unless otherwise stated. When temperatures, pressures and/or wavelengths are not given for the last three named properties, then they should be assumed to be at room temperature (~ 20°C), atmospheric pressure (~ 760mm), and the average of the wavelengths of the sodium D lines respectively; and most densities are relative to water at 4°C unless otherwise stated. When pressure is stated as atm it means that it is not mentioned specifically in the particular literature reference, but assumed to be 760 mm of Hg or 101.325 kPa.

The general formatting like font type and size in Part 2 follows those used in Part 1. Physical data in bold type follow after the formula weight (FW) of each entry as well as inclusion of references to the original literature with the corresponding Digtal Object Identifiers as in Part 1. All molecular weights M following the empirical formulae in previous editions have been replaced by FW because these are indeed the molecular weights that take into account the stable isotopic abundance of specific elements, as e.g. with ³⁵Cl and ³⁷Cl which have a ratio of 100:32.5 for the isotopic atomic weights of the respective atoms in the reported empirical formulae [see Table 26 in Chapter 1 of Purification of Laboratory Chemicals Part 1].

Abbreviations of titles of periodicals are defined as in the Chemical Abstracts Service Source Index (CASSI) but without punctuation. Literature references, and in particular Beilstein references, are included for most entries which refer the reader directly or indirectly to the original sources. References to Fieser & Fieser’s Reagents for Organic Synthesis are shortened to Fieser throughout, e.g. Fieser 2 254, 11 88, etc.

Ionisation constants of ionisable compounds are given as pK values (published in the literature) and refer to the pKa values at room temperature (~ 15°C to 25°C) when the temperature not specified. pKa’s are in H2O, unless stated, and pK values at other temperatures are given as superscripts, e.g. pK ³⁰ for 30°C. Estimated values are entered as pKp st (see Ionisation Constants and bibliography in Chapter 1 of Purification of Laboratory Chemicals Part 1).

Purification of Laboratory Chemicals Part 2

Safety issues should be taken seriously in a scientific laboratory and every effort has been made in Part 2, as was clearly stated in Chapter 1 of Part 1, to alert the laboratory workers of the toxicities of substances described in these volumes. All chemical substances have a threshold at which they begin to exhibit toxicity, some are exceedingly high whereas others are very low. [Refer to Adrien Albert’s Xenobiotics: foods, drugs, and poisons in the human body, Chapman and Hall, 1987, ISBN 0-412-28810-9 Pbk]. In any case, all substances should be considered as poionous unless previous experience dictates otherwise. As a good general rule, all low boiling (< 100 ° ) liquids should be treated as highly flammable and toxic (because they can be inhaled in large quantities) and the necessary precautions should be taken (see Safety precautions associated with the purification of laboratory chemicals in Chapter 1 of Purification of Laboratory Chemicals Part 1).

Therefore, as a matter of routine, eye, face and body protection should be paramount on entering a laboratory, and all experiments should be performed in efficient fume cupboards and in well ventilated laboratories.

Benzene has been used as a solvent successfully and extensively in the past for reactions and purification but is now considered a very dangerous and CARCINOGENIC substance. It should be used with extreme care. We emphasise that alternative solvents (e.g. toluene, toluene-petroleum ether, or a petroleum ether to name a few) should be used first. However, if no other solvent system can be found, then all operations involving benzene (and storage) should be performed in an efficiently running fume hood, and precautions taken to avoid inhalation and contact with skin and eyes. An asterisk has been inserted in the text, e.g. C6H6 or benzene, to remind the user that special precautions should be adopted.

Rapid purification procedures are included for commonly used solvents and reagents which make them suitable for general use in synthetic chemistry. Commercially available polymer supported reagents are indicated with § under the appropriate reagent.

Since the previous editions of Purification of Laboratory Chemicals more and more visual and active, Visual (video) presentations on an extensive repertoire of Chemical, Biological and Medical subjects, both theoretical and experimental, have appeared on line in the internet. They are easy to access from most browsers and are free of charge. Sometimes several presentations of the same subject, e.g. of aromaticity, inorganic chemistry, alkaloids, laboratory safety, etc. are available and some or all can be viewed and compared. On rare occasions the users are asked to donate some money to defray the cost of chemical used to perform the presentation, this is not obligatory. Also, a video presentation of one’s particularly specific choice can be made at a price. Among these ‘free of charge’ presentations are also videos of some Nobel and other notable lectures as well as lectures by distinguished scientists which are well worth viewing.

Safety disclaimer: No responsibility is taken here for any harmful unsuccessful attempts to repeat experiments viewed online. See also < Safety in the chemical laboratory video YouTube > and < Safety in the biochemical laboratory video YouTube > online.

Chapter 1A: Inorganic Compounds

Abstract

The most common method of purifying inorganic species is by recrystallisation, usually from water. However, especially with salts of weak acids or of cations other than the alkaline and alkaline earth metals, care must be taken to minimise hydrolysis. This can be achieved, for example, by recrystallising acetates in the presence of dilute acetic acid. Nevertheless, there are many inorganic chemicals that are too insoluble or are hydrolysed by water so that no general purification method can be given. It is convenient that many inorganic substances have large temperature-solubility coefficients for their solubility in water, i.e. large amounts dissolve in boiling water and on cooling to <25o large amounts of crystals separate. In cases where the temperature-solubility coefficients are small, crystallisation can be achieved by slow partial solvent evaporation.

Keywords

Exothermic reaction; Inorganic compounds; Metal-organic compounds; Mitsunobu reaction; Phosphonic acid; Proatranes; Quasiastranes; Schweizer’s reagent; Somogyi-Nelson’s method; Zinc nano metallic powder

Introduction

The most common method of purifying inorganic species is by recrystallisation, usually from water. However, especially with salts of weak acids or of cations other than the alkaline and alkaline earth metals, care must be taken to minimise hydrolysis. This can be achieved, for example, by recrystallising acetates in the presence of dilute acetic acid. Nevertheless, there are many inorganic chemicals that are too insoluble or are hydrolysed by water so that no general purification method can be given. It is convenient that many inorganic substances have large temperature-solubility coefficients for their solubility in water, i.e. large amounts dissolve in boiling water and on cooling to < 25º large amounts of crystals separate. In cases where the temperature-solubility coefficients are small, crystallisation can be achieved by slow partial solvent evaporation.

Organo-metallic compounds, on the other hand, behave very much like organic compounds, e.g. they can be redistilled and may be soluble in organic solvents. A note of caution should be made about handling organo-metallic compounds, e.g. arsines, phosphines, because of their potential toxicities, particularly when they are volatile. Generally, the suppliers of such compounds provide details about their safe manipulation. These should be read carefully and adhered to closely. If in any doubt, always assume that the materials are lethal and treat them with utmost care. Safety precautions about the handling of substances are detailed in Chapters 1 and 2 in Purification of Laboratory Chemicals Part 1 should be followed here. See also INTRODUCTION to Part 2 in the previous two pages.

For information on ionization constants (pK), see Introduction, of Purification of Laboratory Chemicals Part 2 (in previous two pages), and Chapter 1 of Purification of Laboratory Chemicals Part 1. In order to avoid repetition, the literature (or predicted) pK values of anionic and/or cationic species are usually reported for salts at least once, and in several cases are entered for the free acid or free base; e.g. Na2SO4 will have a pK value for Na+ at the entry for NaOH and the pK values for SO4 ²- at the entries for H2SO4. When the pK values of the organic counter-ions are not given in this chapter, as in case of sodium benzoate (in Chapter IB, Metal-organic Compounds), the reader is referred to the value(s) in Chapter 3, ‘Aromatic Compounds’, e.g. benzoic acid, in Purification of Laboratory Chemicals Part 1.

Alumina (Aluminium oxide) (neutral) [1344-28-1] Al 2 O 3 , FW 102.0 (anhydrous). Stir the oxide with hot 2 M HNO3, either on a steam bath for 12 hours (changing the acid every hour) or three times for 30 minutes, then wash it with hot distilled water until the washings have pH 4 and follow by three washings with hot MeOH. The product is dried at 270º [Angyal & Young J Am Chem Soc 81 5251 1959, DOI: 10.1021/ja01528a055]. For the preparation of alumina for chromatography see Chapter 1. [For α, β and γ Al2O3 see Becher in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 822-823 1963 and Wagner in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p 1662 1965, for chromatography see Fieser 1 19 and in later volumes.] Also commercially available in various physical forms and dryness.

Alumium amalgam (Al-Hg) [11146-30-8] Al.Hg, FW 227.6. This is a good reducing agent for alkali sensitive compounds since the reagent is essentially neutral, e.g. for imines. It is always best to use a fresh preparation. Use as thin an aluminium sheet as possible (~ 40 g) and cut it into small squares (0.5 cm × 0.5 cm) with scissors which produces fresh sharp edges along the sides of the squares. Wash the squares well by decantation with low boiling petroleum ether (to remove any machining grease) then absolute ethanol in a beaker, dry the squares by blowing air over them and cover them with 2.5 N aqueous NaOH (200 mL; 20 g made up to 200 mL with H2O). Warm gently in an efficient fume cupboard until hydrogen evolution is vigorous, ~ 3 minutes. Strain the squares through a plastic colander and wash them first with distilled H2O, then with absolute EtOH, pat them dry with clean tissue paper then add a solution of Hg(II)Cl2 (1 g) in distilled H2O (50 mL) [CARE HgCl2 is very poisonous] to the squares and allow them to amalgamate by stirring them gently with a glass rod for ~ 2 minutes. Pour off the liquid and wash the squares in a plastic colander as previously with distilled H2O, EtOH, and then Et2O. Keep the aluminium amalgam submerged under dry Et2O and use it as soon as possible. The amalgam reacts vigorously with H2O liberating H2 equivalent to the amount of aluminium present in the amalgam. Reductions can be carried out in EtOH, or Et2O by addition of H2O to liberate the nascent hydrogen for reaction in close to neutral media. It has found use in a variety of reactions as well as reductions of double bonds, nitro groups [Monsen & Luzzio Tetrahedron Lett 61(47) 152575 2020, https://doi.org/j.tetlet.2020.152575], and desulfurisations (e.g. of gliotoxin) [See Fieser 1 21; prep: Briody & Cuevas US3619176A 1969, and practical organic texts.]

Aluminium ammonium sulfate dodecahydrate [7784-26-1] AlNH 4 (SO 4 ) 2 . 12H 2 O, FW 453.3, m 93º, m 95º, si1_e , si2_e , si3_e , si4_e [aluminate Al(OH) 4 - ]. Crystallise it from hot H2O and cool in ice. When the melt is heated, it loses NH3 and H2SO4, and gives pure alumina at red heat. Solubility (%) in H2O is 3.9% (0º), 15.0 (20º) and 135 (100º). Crystals for X-ray studies were easily grown in aqueous solution and were ground into spheres about 0.15 mm in diameter [crystal structure: Larson & Cromer Acta Cryst 22 793 1967, DOI: 10.1107/S0365110X67001586].

Aluminium bromide [7727-15-3] AlBr 3 , FW 266.7, m 97º, b 114º/10 mm, si5_e . Reflux it and then distil it from pure aluminium chips in a stream of nitrogen into a flask containing more of the chips. It is then redistilled under vacuum into ampoules [Tipper & Walker J Chem Soc 1352 1959, DOI: 10.1039/JR9590001352]. Anhydrous conditions are essential, and the white to very light brown solid distillate can be broken into lumps in a dry-box (under nitrogen). It fumes in moist air. [Becher in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 812-813 1963, Fieser 1 22 and in 7 later volumes.] Use a good fume cupboard.

Aluminium caesium sulfate dodecahydrate [7784-17-0 (12H 2 O), 14284-36-7] AlCs(SO 4 ) 2 . 12H 2 O, FW 352.1 (anhydr), 568.2, m 110º(dec). Recrystallise it from hot water (3 mL/g).

Aluminium chloride (anhydrous) [7446-70-0] AlCl 3 , FW 133.3, m 192.6º, si6_e . Sublime it several times in an all-glass system under nitrogen at 30-50 mm pressure. It has also been sublimed in a stream of dry HCl and has been subjected to a preliminary sublimation through a section of granular aluminium metal [for manipulative details see Jensen J Am Chem Soc 79 1226 1957, DOI: 10.1021/ja01562a051]. It fumes in moist air. Used in Friedel-Crafts reactions. It is also commercially available as a 0.1 M solution in nitrobenzene [7446-70-0], in functionalised silica gel (70-120 mesh, with a 1.5 mmol/g loading) for use as a Lewis acid and Friedel-Crafts reactions, and as AlCl3.THF complex [192656-42-1] as a 0.5 M solution in THF. Work in good fume cupboard.

Aluminium fluoride (anhydrous) [7784-18-1 (anhydr), 32287-65-3 (H 2 O), 15098-87-0 (3H 2 O)] AlF 3 , FW 84.0 (anhydr), m 1292º(subliming), d ²⁵ 3.1g/cm ³ (anhydr). The technical material may contain up to 15% alumina, and minor impurities such as aluminium sulfate, cryolite, silica and iron oxide. Reagent grade AlF3 (hydrated) contains only traces of impurities, but its water content is variable (and may be up to 40%). It can be dried by calcining at 600-800º in a stream of dry air (some hydrolysis occurs), followed by vacuum distillation at low pressure in a graphite system, heated to approximately 925º (condenser at 900º) [Henry & Dreisbach J Am Chem Soc 81 5274 1959, DOI: 10.1021/ja01529a003]. Its solubility in H2O is 0.5%. [Kwasnik in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 225-226 1963, Aigueperse et al. ‘Fluorine Compounds, Inorganic’ in Ullmann’s Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2005, DOI: https://doi.org/10.1002/14356007.a11_307.] Work in a good fume cupboard.

Aluminium nitrate nonahydrate [7784-27-2 (9H 2 O); 13473-90-0 (anhydr)] Al(NO 3 ) 3 . 9H 2 O, FW 375.1, m 72.8º, 73º, 73.5º, b 135º/atm, d ²⁵ 1.72g/cm ³ . Crystallise the nitrate from dilute HNO3, and dry it by passing dry nitrogen through the crystals for several hours at 40º. After 2 recrystallisations of ACS grade, it had S, Na and Fe at 2.2, 0.01 and 0.02 ppm, respectively.

Aluminium potassium sulfate dodecahydrate (Alum) [7784-24-9] AlK(SO 4 ) 2 . 12H 2 O, FW 474.4, m 92º, d ²⁵ 1.757g/cm ³ . Crystallise it from weak aqueous H2SO4 (ca 0.5 mL/g). Its solubility (%) in H2O is 5.7 (0º), 12.0 (20º) and 136.9 (100º). Crystals for X-ray studies were easily grown in H2O solution and were ground into spheres about 0.15 mm in diameter [crystal structure: Larson & Cromer Acta Cryst 22 793 1967, DOI: 10.1107/S0365110X67001586].

Aluminium rubidium sulfate dodecahydrate [7784-29-4, 1350-57-9 (anhydr)] AlRb(SO 4 ) 2 . 12H 2 O, FW 520.8, 304.6 (anhydr), m 99-109º, 100º(dec), d 1.90g/cm ³ . Crystallise the double salt from aqueous H2SO4 (ca 2.5 mL /g). Crystals for X-ray studies were easily grown in aqueous solution and were ground into spheres about 0.15 mm in diameter. It is insoluble in EtOH. [Prepn: Gmelin’s, Aluminium (8th edn) 35B p 525-527 1934; crystal structure: Larson & Cromer Acta Cryst 22 793 1967, DOI: 10.1107/S0365110X67001586.]

Aluminium sulfate (anhydrous) [10043-01-3] FW 342.2(anhydr), m 765º(dec), d ²⁵ 2.71g/cm ³ , Al 2 (SO 4 ) 3 14-18 H 2 O [17927-65-0] , d ²⁵ 1.69g/cm ³ , Al 2 (SO 4 ) 3 18 H 2 O [7784-31-8] . It crystallises from hot dilute H2SO4 (l mL/g) on cooling in ice. When a solution of alumina (Al2O3) in concentrated H2SO4 is slowly cooled, Al2(SO4)3 17 or 18H2O deposits as a crystalline mass. Al2(SO4)3 17H2O is the stable form in equilibrium with its saturated aqueous solution at 25º [Smith J Am Chem Soc 64 41 1942, DOI: 10.1021/ja01253a012]. This is purified by dissolving it in a small volume of H2O and adding EtOH until the sulfate readily crystallises from the oily supersaturated solution. It forms Al2(SO4)3 16H2O between 0-112º. On gradual heating, the hydrate melts, giving the anhydrous salt at ca 250º. Several hydrates up to 27H2O have been described. Further heating to red heat (~ 600-800º) causes decomposition to Al2O3 + SO3 + SO2 and O2 [Cobb J Soc Chem Ind 29 250 1910]. The ACS reagent is Al2(SO4)3 18H2O (98 +%).

Ammonia (gas) [7664-41-7] NH 3 , FW 17.0, pK ²⁵ 9.25. Major contaminants are water, oil and non-condensable gases. Most of these impurities are removed by passing the ammonia through a trap at -22º and condensing it at -176º under vacuum. Water is removed by distilling the ammonia into a tube containing a small lump of sodium. Also dry it by passage through porous BaO, or over alumina followed by glass wool impregnated with sodium (prepared by soaking the glass wool in a solution of sodium in liquid ammonia and evaporating off the ammonia). It can be rendered oxygen-free by passage through a solution of potassium in liquid ammonia. [Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 460-463 1963.] AMMONIA (gas, liquid or aqueous solution) is very irritating and should not be inhaled in any quantity as it can lead to olfactory paralysis (temporary or permanent).

Ammonia (liquid) [7664-41-7] NH 3 , FW 17.0, m -77.8º, b -33.35º, si7_e , si8_e , d -79 0.817g/mL. Dry the liquid, and store it, with sodium in a steel cylinder, then distil and condense it by means of liquid air, the non-condensable gases being pumped off. In order to obtain liquid NH3 from a cylinder, turn the cylinder upside-down (i.e. with the valve at the bottom, use a metal stand to secure it in this position; a special stand can be constructed for it) and lead a plastic tube from the tap to a measuring cylinder placed in an efficient fume cupboard which is kept running. Turn the tap on and allow the ammonia to be released. At first, gas and liquid will splutter out (make sure that the plastic tube is secure), but soon liquid will drip into the measuring cylinder. The high latent heat of evaporation will cool the ammonia so that the liquid will remain cool and not boil vigorously. If the ammonia is required dry, the necessary precautions should be taken, i.e. the gas is allowed to flow through tubes packed with coarse CaO pellets. AMMONIA (gas, liquid or aqueous solution) is very irritating and should not be inhaled in any quantity as it can lead to olfactory paralysis (temporary or permanent).

Ammonia (aqueous) [7664-41-7] NH 3 . xH 2 O, FW 17.0 + H 2 O, si9_e (saturated, 27% w/v, 14.3 N), pK ²⁵ 9.25 (pKb at 25º = 4.75, i.e. pKa = 14.00-4.75 = 9.25, or K b = 1.81 × 10 -5 ). Obtained metal-free by saturating distilled water, in a cooling bath, with ammonia (from a cylinder) gas. Alternatively, isothermal distillation can be used by placing a dish of concentrated aqueous ammonia and a dish of pure water in an empty desiccator and leaving to equilibrate for several days. AMMONIA (gas, liquid or aqueous solution) is very irritating and should not be inhaled in any quantity as it can lead to olfactory paralysis (temporary or permanent).

Ammonium bisulfate (Ammonium hydrogen sulfate) [7803-63-6] (NH 4 ) HSO 4 , M 115.1, m 121-145º, ~ 147º, si10_e , pK ²⁵ 1.96 (HSO 4 - ). It crystallises from water at room temperature (1 mL/g) on adding EtOH and cooling. (NH4) HSO4 is formed as deliquescent rhombic crystals on cooling a solution of (NH4)2SO4 in hot concentrated H2SO4 but EtOH decomposes it to (NH4)3H(SO4)2. Alternatively, if the salt is slightly acidic, it is extracted (Soxhlet) with dry Et2O (no reaction) until the runnings are neutral. This is the most efficient way of purifying (NH4) HSO4, m 145º, free from traces of H2O and H2SO4. It is extremely hygroscopic and should be stored in glass bottles in desiccators. When (NH4) HSO4 is shaken with 5 to 7 times its weight of EtOH (dried over lime or CaC2 and distilled with b 77.1-77.2º/726 mm) for 18 hours, filtered quickly then extracted with Et2O (Soxhlet) until the washings are neutral (litmus), a salt with the formula (NH4)3H(SO4)2 is produced. This salt is not deliquescent and decomposes before melting. [Dunnicliff J Chem Soc 123 476 1923, DOI: 10.1039/CT9232300476; Gmelin’s, Ammonia [8th Ed.] 23 405-406 1936.]. When powdered (NH4)2SO4 is heated in a Pt dish below 100º, it loses NH3, and at 300º it is completely converted to fused (NH4) HSO4, m 140º, but > 300º it decomposes to SO2 and N2 [Smith J Soc Chem Ind 14 629 1895, 15 3 1896]. [Dunnicliff J Chem Soc 123 731 1923, DOI: 10.1039/CT9232300731.] Used in hair waving and as a source of weak acid.

Ammonium bromide [12124-97-9] NH 3 HBr, FW 98.0, m 450º(sublimes), si11_e . It crystallises from 95% EtOH and is slightly hygroscopic.

Ammonium chloride [12125-02-9] NH 3 HCl, FW 53.5, m 338º (sublime point, without melting), si12_e . Crystallise it several times from conductivity water (1.5 mL/g) between 90º and 0º. It sublimes. The salt is fully ionised in aqueous solution, i.e. K ≈ ∞. A 1 M aqueous solution of NH4Cl has a pH of ~ 4.7, i.e. is acidic. After one crystallisation, ACS grade has: metal(ppm) As (1.2), K (1), Sb (7.2), V (10.2). [Becher in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 812 1963.]

Ammonium chromate [7788-98-9] (NH 4 ) 2 CrO 4 , FW 152.1, m 185º(dec), si13_e , si14_e , si15_e (for H 2 CrO 4 ). Crystallise it from weak aqueous ammonia (ca 2.5 mL/g) by cooling from room temperature. It loses NH3 on heating to form ammonium dichromate (below). [Prepn: Gmelin’s, Chromium (8th edn) 52B p 707-712 1962.] Used as a reagent in analytical chemistry, in textile and wool dyeing, and in sensitising photographic gelatin. POISONOUS.

Ammonium dichromate [7789-09-5] (NH 4 ) 2 Cr 2 O 7 , FW 252.1, m 170º(dec), si16_e . It crystallises from weak aqueous HCl (ca 1 mL/g). It decomposes rapidly on heating. (Possible carcinogen, irritates skin possibly forming chrome sores , and is POISONOUS)

Ammonium dihydrogen arsenate [13462-93-6] (NH 4 )H 2 AsO 4 , FW 159.0, Sp gr 2.311g/mL, n 1.577, m 300º(dec). Crystallise it from water (1 mL/g). POISONOUS.

Ammonium dihydrogen orthophosphate [7722-76-1] (NH 4 )H 2 PO 4 , FW 115.0, m 190º(dec), si17_e . Crystallise it from water (0.7 mL/g) between 100º and 0º. It is slightly soluble in EtOH and insoluble in Me2CO. With NaHCO3 (a baking powder), it is used in fermentation and culture media. It is a fire retardant for paper and related fibrous materials.

Ammonium ferric sulfate dodecahydrate [7783-83-7 (12H 2 O), 10138-04-2 (anhydrous)] (NH 4 )Fe(SO 4 ) 2 . 12 H 2 O, FW 482.2, m ~ 37º, 39-41º, si18_e . Crystallise it from aqueous ethanol. Its solubility is 1 M in dilute HCl, and 1.24 g/100 mL in H2O.

Ammonium ferrous sulfate hexahydrate [Mohr’s salt] [7783-85-9 (6H 2 O), 10045-89-3 (anhydrous)] (NH 4 ) 2 Fe(SO 4 ) 2 . 6 H 2 O, FW 392.1, 284.05(anhydr), m 100º(dec), si19_e . A solution in warm water (0.67 g/mL) is cooled rapidly to 0º, and the resulting light bluish-green monoclinic crystals are filtered at the pump, washed with cold distilled water and pressed between sheets of filter paper to dry it. The solubility at 25º is 0.36 g/ mL. It separates as an almost white powder when a saturated aqueous solution is diluted with EtOH.

Ammonium hexabromoosmate (IV) [24593-62-7] (NH 4 ) 2 OsBr 6 , FW 705.7, m 170º(sublimes), d ²⁵ 2.93g/mL. The salt is prepared by dissolving osmic acid [Os(VIII)O4, 1 g 0.004 mol, HIGHLY TOXIC: take all due precautions to protect skin, eyes, mouth and body) immediately into 47% hydrobromic acid (36 mL) and refluxing for 2 hours, additional HBr (7 mL) is added, then to the hot solution is added ammonium bromide (3 g, 0.03 mol), and when the bromide dissolves completely, the mixture is cooled to 20º, absolute EtOH (50 mL) is added with stirring whereby a dense black solid separates, is allowed to settle, washed by decantation with absolute EtOH until the washings are free from bromide ions. The residue is filtered off onto a sintered glass funnel and washed with EtOH until the filtrate gives no turbidity with ethanolic AgNO3 solution. [Small amounts of H2O may allow some residue to dissolve giving the washings a yellow tint; ethanolic AgNO3 gives a bluish colour of colloidal Ag2OsBr6 in the washings but the sensitivity of the test is not seriously affected.] After drying at 140º, the residue (2.7 g, 96% yield) consists of minute black crystalline cubes and octahedra which are sparingly soluble in cold H2O producing a red solution, but in hot aqueous solutions black osmium (IV) oxide, OsO4, is deposited. The salt is soluble in warm glycerol and ethylene glycol but insoluble in MeOH or EtOH. [Dwyer & Hogarth Inorg Synth 5 204 1957, https://doi.org/10.1002/978470132364.ch59.] It is a hygroscopic solid which could be stored under N2 in the dark at 20º.

Ammonium hexachloroiridate (IV) [16940-92-4] (NH 4 ) 2 IrCl 6 , FW 441.0, d ²⁵ 2.86 g/mL. It is precipitated several times from aqueous solution by saturation with ammonium chloride and is a reddish-black sparingly soluble solid. This removes any palladium and rhodium. It is then washed with ice-cold water and dried over concentrated H2SO4 in a vacuum desiccator. If osmium or ruthenium is present, it can be removed as the tetroxide by heating with concentrasted HNO3, followed by concentrated HClO4, until most of the acid has been driven off. (This treatment is repeated.) The near-dry residue is dissolved in a small amount of water and added to excess NaHCO3 solution and bromine water. On boiling, iridic (but not platinic) hydroxide is precipitated. It is dissolved in HCl and precipitated several times, then dissolved in HBr and treated with HNO3 and HCl to convert the bromides to chlorides. Saturation with ammonium chloride and cooling precipitates ammonium hexachloroiridate which is filtered off and purified as above [Woo & Yost J Am Chem Soc 53 884 1931, DOI: 10.1021/ja01354a008]. This commercially important iridium compound is the most common complex of Ir(IV) [Renner et al. ‘Platinum group metals and compounds’ in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley 2002, DOI: https://doi.org/10.1002/14356007.a21_075].

Ammonium hexachloroosmate (IV) [12125-08-5] (NH 4 ) 2 OsCl 6 , FW 439.0, m 170º(sublimes), d ²⁵ 2.93 g/mL. The salt is prepared by dissolving osmic acid [Os(VIII)O4, 1 g, 0.004 mol, HIGHLY TOXIC: take all due precautions to protect skin, eyes, mouth and body) in 12 M HCl (30 mL, 0.36 mol) and Fe(II)Cl2.6H2O (10 g, 0.043 mol) or Fe(II)Cl2.4H2O (0.050 mol) is added, and heated on a steam bath with occasional swirling for 2 hours, whereupon the deep green colour turns to red-orange, and then 20% ammonium chloride solution (10 mL, 0.04 mol) is added and the mixture is cooled in ice. The desired salt separates, is washed by decantation with 80% EtOH, transferred to a sintered-glass funnel and filtered off, washed with absolute EtOH until free from chloride ions, the dried at 120º to yield ammonium hexachloroosmate (1.57-1.63 g, 91-94% yield). [Dwyer & Hogarth Inorg Synth 5 206 1957, https://doi.org/10.1002/978470132364.ch60.] This osmate salt forms dark red octahedral and cubic crystals or a red powder which is sparingly soluble in cold H2O (to give a green-yellow solution) and in EtOH. It is hygroscopic. Use gloves, eye protection and protective clothing as it is an irritant, affecting the skin, eyes and should not be breathed in. Use a well ventilated fumehood. Wash it off the skin with H2O.

Ammonium hexacyanoferrate II hydrate [14481-29-9] (NH 4 ) 4 [Fe(CN) 6 ]. xH 2 O, FW 284.1, m dec on heating. The pale yellow trihydrate powder can be washed with 10% aqueous NH3, filtered, then washed several times with EtOH and Et2O, and dried at room temperature. It decomposes in a vacuum above 100º and should be stored away from light and under N2. In light and air it decomposes by losing NH3. [Lux in Handbook of Preparative Inorganic Chem (Ed. Brauer) Academic Press Vol II p 1509 1965; Gmelin’s, Iron (8th edn) 59B p 1024 1932.] Used as a spot test reagent for Ca [Feigl, Tüpfelanalyse, Anorganischer Teil Akadem Verlager, Frankfurt/Main, p228 1960].

Ammonium hexafluorophosphate [16941-11-0] NH 4 PF 6 , FW 163.0, si20_e , si21_e , si22_e (for fluorophosphoric acid H 2 PO 3 F). It crystallises from H2O in square plates and decomposes on heating before melting. Its solublility in H2O at 20º is 74.8% w/v, and it is very soluble in Me2CO, MeOH, EtOH and MeOAc, but is decomposed by boiling mineral acids. It does not etch glass. [Lange & Müller Chem Ber 63 1058 1930, DOI: 10.1002/cber.19300630510; Woyski et al. Inorg Synth 3 111 1951, DOI: 10.1002/9780470132340.ch29; Kwasnik in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 195 1963.]

Ammonium hexafluorosilicate [16919-19-0] (NH 4 ) 2 SiF 6 , FW 178.1, d ²⁵ 2.01g/mL, pK 2 1.92 (for H 2 SiF 6 ). Crystallise the salt from water (2 mL/g). After 3 recrystallisations, the Technical grade salt has Li, Na, K and Fe at 0.3, 0.2, 0.1 and 1.0 ppm respectively. Used as a flux in soldering and for etching glass. [Gmelin’s, Ammonium (8th edn) 23 p414-415 1936.]

Ammonium hypophosphite (Ammonium phosphinate) [7803-65-8] NH 4 . H 2 PO 2 , FW 83.0, m 155-160º. Crystallise it from hot EtOH. Its solubility in H2O at ~ 25º is 1 g/mL, and it liberates PH3 (TOXIC) at ~ 240º.

Ammonium iodate [13446-09-8] NH 4 IO 3 , FW 192.9, m 150º(dec), d ²⁵ 3.309g/mL, pK ²⁵ 0.79 (IO ³- ). Ammonium iodate crystallises from water (8 mL/g) on cooling from 100º to 0º.

Ammonium iodide [12027-06-4] NH 4 I, FW 144.9, sublimes with dec at ~ 405º, si23_e . The iodide crystallises from EtOH on addition of ethyl iodide, and is very hygroscopic. Store it in a tightly stoppered bottle, in the dark. Its solubility is 0.4 g/mL in MeOH, 0.27 g/mL in EtOH, 0.67g/mL in glycerol, and 1.67 g/mL in H2O at 25º, and 2.0 g/mL in H2O at ~ 100º. [Schmeisser in Handbook of Preparative Inorganic Chem (Ed. Brauer) Academic Press Vol I p 289-290 1963.]

Ammonium magnesium chloride hexahydrate [60314-43-4 (12H 2 O), 12125-06-3 (anhydrous)] NH 4 Cl MgCl 2 , FW 256.8, 148.7(anhydr). It crystallises from water (6 mL/g) by partial evaporation in a desiccator over KOH (deliquescent).

Ammonium magnesium sulfate hexahydrate [20861-69-2] NH 4 MgSO 4 . 6H 2 O, FW 246.4, 138.4(anhydr). It crystallises from water (1 mL/g) between 100º and 0º.

Ammonium manganous sulfate hexahydrate (Diammonium manganese II sulfate hexahydrate) [7785-19-5, 13566-22-8] (NH 4 ) 2 SO 4 .MnSO 4 . 6H 2 O, FW 391.3, 138.4(anhydr). It crystallises from water (2 mL/g) by partial evaporation in a desiccator.

Ammonium molybdate [13106-76-8] (NH 4 ) 2 MoO 4 , FW 196.0, si24_e (proton addition), si25_e , si26_e (for H 2 MoO 4 ). Crystallise the salt from water (2.5 mL/g) by partial evaporation in a desiccator. When a solution of MoO3 in excess of hot concentrated NH3 is cooled, normal ammonium molybdate (NH4)2MoO4 crystallises out. However, when this solution is made to evaporated which allows the pH to drop to 6, the common hydrated ammonium paramolybdate (NH4)6Mo7O24 4H2O {or 3[(NH4)2O]. 7MoO3. 4H2O, [12054-85-2] FW 1235.9} crystallises out. This was an old formula which was confirmed by Sturdivant. [Sturdivant J Am Chem Soc 59 630 1937, DOI: 10.1021/ja01283a010; Grüttner & Jauder in Handbook of Preparative Inorganic Chem (Ed. Brauer) Academic Press Vol II p 1711 1965.]

Ammonium nickel (II) sulfate hexahydrate [7785-20-8 (6H 2 O), 15699-18-0 (anhydrous)] (NH 4 ) 2 Ni(SO 4 ) 2 . 6H 2 O, FW 395.0, m 58-89º, si27_e .Crystallise this salt from water (3 mL/g) on cooling from 90º to 0º.

Ammonium nitrate [6484-52-2] NH 4 NO 3 , FW 80.0, m 165º(moist salt), 169º, 169.6º, b 210º/atm(dec explosively), si28_e . It is crystallised twice from distilled water (1 mL/g) by adding EtOH, or from warm water (0.5 mL/g) by cooling in an ice-salt bath. Its solubility in H2O is 1.18 g/ mL (0º), 1.5 g/ mL (20º), 2.3 g/ mL (40º), 4.1 g/mL (60º), 5.76 g/ mL (80º) and 10.2 g/ mL (100º). Dry it in air, then under vacuum. After 3 recrystallisations of ACS grade, it contained Li and B at 0.03 and 0.74 ppm, respectively. It is deliquescent . [Early & Lowry J Chem Soc 115 1387 1919, DOI: 10.1039/CT9191501387; 121 963 1922, DOI: 10.1039/ CT9222100963; Hendricks et al. J Am Chem Soc 54 2766 1932, DOI: 10.1021/ja01346a020.] It is a high nitrogen fertiliser in agriculture, a useful explosive in mining and ammunition and should be handled with care.

Ammonium perchlorate [7790-98-9] NH 4 ClO 4 , FW 117.5, si29_e , pK ²⁵ -2.4 to -3.1 (for HClO 4 ). It is recrystallised twice from distilled water (2.5 mL/g) between 80º and 0º; and dried in a vacuum desiccator over P2O5. Drying at 110º might lead to slow decomposition to the chloride. Useful in pyrotechnic materials and rocket propellants. [Jacobs & Whitehead Chem Rev 69 551-50 1969, DOI: 10.1021/cr60260a005; Gmelin’s, Ammonium (8th edn) 23 p 196-200 1936.] POTENTIALLY EXPLOSIVE.

Ammonium persulfate (APS, ammonium peroxydisulfate) [7727-54-0] (NH 4 ) 2 S 2 O 8 , FW 228.2, m dec when heated wet liberating oxygen, si30_e . Recrystallise it at room temperature from EtOH/water. It is freely soluble in H2O: 0.5 (0.11) g/mL at 20º, and 2 g/mL at 100º, also soluble in MeOH, but less so in EtOH and Me2CO, and insoluble in most other organic solvents. Stable when pure and dry but decomposes when moist evolving O2 and O3, and gradually loses NH3 on exposure to air. It is a bleacher and a free radical initiator being used for polymerising acrylamide gels. [Feher in Handbook of Preparative Inorganic Chem (Ed. Brauer) Academic Press Vol I p 190 1963, Fieser 1 952, 2 348, 3 238, 5 5, 5 15, 6, 20, 12 33.]

Ammonium reineckate (Reineckate salt) [13573-16-5] NH 4 [Cr(NH 3 ) 2 (SCN) 4 ], FW 336.4 (anhydrous), m 268-272º(dec), 270-273º(dec), d 1.49g/cm ³ . Crystallise this dark red solid from water, between 30º and 0º, while working under artificial light. Solutions of reineckate salt (aqueous or alcoholic) decompose slowly at room temperature in the dark (~ 2 weeks) and more rapidly at higher temperatures or in diffuse sunlight. The solutions are blue in colour and liberate HCN (POISONOUS). Store it dry in the dark under a vacuum. [Dakin Org Synth Coll Vol 2 555 1943, DOI: 10.15227/orgsyn.015.0074.] Used to precipitate primary, secondary amines and some amino acids, e.g. crystalline products with proline and hydroxyproline, and gives a red colour or precipitate with Hg² + compounds.

Ammonium selenate [7783-21-3] (NH 4 ) 2 SeO 4 , FW 179.0, si31_e , m dec on heating. Crystallise the selenate from water at room temperature by adding EtOH and cooling. Its solubility in H2O is 117% at 7º and 197% at 100º. [King J Phys Chem 41 797 1937, DOI: 10.1021/j150384a003.] Used for mothproofing.

Ammonium sulfamate [7773-06-0] NH 4 NH 2 SO 3