The final chapter introduces the chemistry of anthracene, phenanthrene, and polycyclic aromatic hydrocarbons. Voir la suite Organic Chemistry for General Degree Students, Volume 2: Aromatic Chemistry covers the simple heteroaromatic systems and the chemistry of their functional groups. Compounds containing carbon—carbon multiple bonding are called unsaturated to distinguish them from those saturated compounds in which all the carbon—carbon bonds are single. For example, benzene does not decolorise a solution of bromine in carbon tetrachloride, a reagent commonly used for the detection of unsaturation. The book can provide useful information to scientists, chemists, students, and researchers. Most of the standard procedures for the determination of molecular weights, descriptions of which may be found in textbooks of physical chemistry, may be applied to organic compounds.
It was clearly realized by the early organic chemists that no attempt could be made on the structural elucidation of a particular compound until both the nature and relative proportions of the elements present in its molecule had been determined. In this volume we have endeavoured to cover the important fundamental aspects of aromatic chemistry, including simple heteroaromatic systems, to a level which, broadly speaking, is adequate to meet the requirements of students reading for a B. Qualitative Analysis Those organic substances which contain metallic elements leave behind an incombustible residue after ignition which may be submitted to the usual methods of inorganic qualitative analysis. The nature of the halogen may be deduced in the usual way. This approach led to the establishment of the principal methods of qualitative and quantitative elemental analysis of organic substances. A blue precipitate of ferric ferrocyanide Prussian blue indicates the presence of nitrogen in the original substance.
The succeeding chapters explore the analysis and general reactions of nucleophilic replacements, as well as the synthesis of sulfonic acid derivatives. By the Dumas method, another sample 3·250 mg gave nitrogen 0·17 ml after correction to S. The organization of the subject-matter in this volume into the main functional classes is largely conventional but we have attempted to provide a comprehensive yet concise treatment of the principal general methods of preparation and reactions of the main aliphatic classes together with adequate practical detail, particularly concerning preparative methods of industrial importance. The halide ion is detected by acidifying a portion of the fusion extract with nitric acid and boiling to expel hydrogen cyanide or sulphide if these are present. First edition 1969 Library of Congress Catalog Card No. The first chapters discuss the benzene structure and reactivity; nitro compounds and aromatic nitration; aromatic and side-chain halogenated compounds; general properties of aromatic sulfonic acids; and the mechanism of sulfonation.
This book is divided into 11 chapters that also describe the properties of the aromatic compounds. The first chapters discuss the benzene structure and reactivity; nitro compounds and aromatic nitration; aromatic and side-chain halogenated compounds; general properties of aromatic sulfonic acids; and the mechanism of sulfonation. The cyanide ion is detected by adding aqueous ferrous sulphate solution to a portion of the extract, boiling to achieve some aerial oxidation of ferrous ions to ferric ions, and acidifying with sulphuric acid. This enables the relative atomic proportions of the molecule to be calculated and from the molecular weight of the substance, the absolute number of atoms of each element present in one molecule of the organic compound is ascertained. The sulphide ion is detected in the aqueous extract by the addition of a solution of sodium nitroprusside, when an unmistakable violet coloration is produced if sulphide ions are present.
The first chapters discuss the benzene structure and reactivity; nitro compounds and aromatic nitration; aromatic and side-chain halogenated compounds; general properties of aromatic sulfonic acids; and the mechanism of sulfonation. The molecular formula must therefore be determined from a knowledge of the empirical formula and the molecular weight of the compound, from which it will be readily apparent whether the molecular formula is the same as the empirical formula or some simple multiple thereof. In this new fifth edition, in order to ensure that the book retains its relevance to current teaching of organic chemistry, we have adopted the same structure of the book since we are of the opinion that it provides a bridge between the treatment of organic chemistry theory provided by current standard undergraduate textbooks, and the wider specialist fields of the research literature. In fact four simultaneous thought-processes are likely to be adopted: a a postulation of possible structural formulae, b a consideration of the chemical reactivity of the compound, c a knowledge of how the compound has been prepared with a natural product this information is not, of course, available, and in this case an attempt is made to confirm the assigned structure by synthesis , and d a knowledge of the nature of the products obtained as a result of its further reactions. Details of methods used are to be found in suitable textbooks on practical organic chemistry, but the principles of these procedures are outlined below.
Preface Our object in writing a new textbook of organic chemistry has been to meet the particular needs of students reading for the B. It was then possible to embark upon studies directed towards the elucidation of the manner in which the individual atoms in a molecule of the pure compound were linked together i. The decision to separate the aromatic section from the aliphatic was intentional rather than one of convenience. The book can provide useful information to scientists, chemists, students, and researchers. For example, benzene does not decolorize a solution of bromine in carbon tetrachloride, a reagent commonly used for the detection of unsaturation. A detailed study of the reactions of benzene and its derivatives therefore formed the basis of aromatic chemistry as it is now known and aromatic chemistry may be defined as the chemistry of compounds having the characteristic chemical properties of benzenoid compounds. We gratefully acknowledge the interest shown in this project by Dr.
Some of the problems are designed to enable the student to extend his knowledge of a particular topic beyond the actual examples given in the text. Organic chemistry is the chemistry of carbon compounds excluding such compounds as the carbonates, bicarbonates, carbon monoxide and the metallic carbonyls. These topics are followed by discussions on the basic properties of phenols and the reactions involving hydroxyl group. A convenient technique is to drop some of the compound to be examined on to sodium pre-heated in a Pyrex test-tube. It was clearly realized by the early organic chemists that no attempt could be made on the structural elucidation of a particular compound until both the nature and relative proportions of the elements present in its molecule had been determined. With a more complex molecular formula it becomes difficult to write down per se all the possible structural formulae and it is usually needless to do so, without first considering all the relevant chemical information which may greatly limit the number of possible structures. Both these theoretical treatments lead to a similar picture of benzene as a symmetrical hexagonal molecule which possesses a lower energy as a result of electron delocalisation than that expected from a molecule represented by a classical cyclohexatriene structure.
This classification was largely one of convenience since aromatic compounds so named because many of the earliest examples isolated from plant extracts had pleasant aromas were found to possess chemical properties which were characteristically different from those of the aliphatic group. The composition of the compound is therefore: Dividing each value by the atomic weight of the element: or Dividing each value by 0·465: These figures may now be rounded off to the nearest whole numbers to give the empirical formula, i. An Introduction to the Chemistry of Benzenoid Compounds is an introductory text to some chemical aspects of benzenoid compounds. Organic substances were always found to give carbon dioxide and water upon burning in oxygen, showing the presence of the elements carbon and hydrogen. The subsequent chapters deal with the disubstitution and addition reactions of the benzene nucleus.