Geneva System

This was a great advance, as complex hydrocarbons of various kinds could be clearly named if their stmctures were known. The Geneva system, modified and expanded by subsequent Commissions, is used systematically in the fourth and fifth editions of Be /stem s Handbuch der Organischen Chemie (1), and as the basis of lUPAC nomenclature. In 1992 a commemorative symposium on the centennial anniversary of the Geneva Conference was held in Geneva (45). 

A further complication that may be encountered in the nomenclature of branched-chain monosaccharides is in the numbering of the carbon atoms of the molecule. There is some precedent for numbering the carbon atoms of the branched moiety continuously with the carbon atoms of the main chain. However, this can result in confusion and ambiguity, especially when there are further substituents on the branched carbon atoms. In this connection, the Geneva system of nomenclature11 provides a reasonable solution, which is illustrated in the naming of compounds XII10 and XIII. 

The Geneva system makes use of some of the ideas of both broad- and intermediate-band systems, being similar to UBV but with the B and V each... 

An important modification of the Geneva system is that the fundamental chain used as a basis in an aliphatic compound is not necessarily the longest chain in the molecule, but must be the longest chain of those containing the maximum number of occurrences of the principal functional group I Rule 18). This shifts the importance for naming from side chains such as methyl and ethyl to functional groups such as -COOH and — OFF... 

The nomenclature used throughout the book has been amended. The principal names are those adopted by the Chemical Society. Alternative names—which are in some cases the English equivalent of the usual German names, and in others are based on the Geneva System—are given in most instances to assist the student in making reference to the original literature. 

According to the Geneva system these hydrocarbons are named in the same way as the paraffins except that the suffiix -ene is used instead of -ane. However, the first tliree members of this series are more commonly referred to as ethylene, propylene, and butylene instead of ethene, propene, and butene. Tbia is due to the survival of an older system of nomenclature. For the higher members of this series, the more modern suffix -ene is usually employed instead of the older -ylene. 

Isomerism occurs in the olefins just as it does in the paraffins. Not only is it due to branching of the carbon chains but the position of the double bond in the molecule is also a source of isomerism. Thus, a molecule of butene, or butylene, with the double bond between the first and second carbons has properties quite different from that with the double bond between the second and tliird carbons. The Geneva system distinguishes tliese two isomers by adding a number at the end of the name. This number indicates the lowest numbered carbon atom involved in the double bond. Thus,... 

Another series of unsaturated hydrocarbons is known as the diolefins. They are characterized by the fact that there are two double bonds in the molecule. The general formula for this series is C H2 -2-To name these compounds by the Geneva system tire suffix -adiene is used and the positions of the two double bonds are indicated by two numbers placed after the name. For example,... 

Draw structural formulas for the isomers of heptane. Name the isomers by the Geneva system. 

General gas law, 18 Geneva system, 5, 7, 8 Gibb s phase rule, 75 S. 

The Geneva system is a method of nomenclature which does not have this disadvantage since it is applicable to even the most complex hydrocarbons. To use this method it is first necessary to pick out the longest continuous chain of carbon atoms in the molecule and number them consecutively. The compound is considered to be a derivative of this longest continuous chain hydrocarbon. The various alkyl groups attached to this chain are named in the usual manner and their position is indicated by the number of the carbon atom to which they are joined. For example, for isopentane, there are four carbons in a... 

Sulfides, disulfides, sulfoxides, and sulfones are named like ethers, the oxy term being replaced with thio-, dithio-, sulfinyl, and sulfonyl. The acids are also named in accordance with the Geneva System. 

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