Identifiers chemical names, systematic

Chemical Designation - A list of common synonyms is given. Synonym names are alternative systematic chemical names and commonly used trivial names for chemicals. An index of synonyms is provided at the end of the handbook to assist the reader in identifying a particular chemical and researching chemical hazards information in the event that the common name of the chemical is not known. The data field also contains the chemical formula. The chemical formula is limited to a commonly used one-line formula. In the case of some organic chemical compounds it has not been possible to represent the chemical structure within such limitation. 

Identify the materials used and give information on the degree of and criteria for purity, but do not reference standard laboratory reagents. Give the chemical names of all compounds and the chemical formulas of compounds that are new or uncommon. Use meaningful nomenclature that is, use standard systematic nomenclature where specificity and complexity require, or use trivial nomenclature where it will adequately and unambiguously define a well-established compound. 

There are millions of chemicals in our world, and likely millions more to be identified. Long ago chemists recognized this and they developed systematic ways to name chemicals—a process known as systematic nomenclature. About 100 years ago the American Chemical Society s Chemical Abstracts Service (CAS) developed a system of identifying chemicals with unique numbers—these are known as CAS numbers. You will find that it is not unusual for chemicals to have multiple names, but there will always be only one CAS number. (See Special Topic 3.1.2.1 Finding the CAS Number for a Chemical.) Let s look at an example. 

Table 1. Formaldehyde and formaldehyde-releasing preservatives registered in the Danish Product Register Database (PROBAS) January 1998 and February 1992 identified with CAS RN, systematic chemical names and synonyms...

Since systematic chemical name fragments and molecular formula fragments are also found in the RTECS file, one can use CHEMLINE nomenclatural output to perform a substructure search that is correlated with a biological concept in RTECS. This would obviate the need to carry the chemical identifiers for the forty CHEMLINE records into the RTECS file. 

In addition to their systematic names, many simple alkyl halides are also named by identifying first the alkyl group and then the halogen, for example, CH3T can be called either iodomethane or methyl iodide. Such names are well entrenched in the chemical literature and in daily usage, but they won t be used in this book. 

Systematic names describe the molecular structure of a compound. A systematic name consists of two parts, . The is the name of a compound having a particular caibon skeleton. The are a list of one or more radical groups connected by chemical bonds to the parent compound. Substituents are arranged in alphabetical order within a compound name. If the parent contains more than one carbon atom, each substiuent name is preceded by a number identifying the carbon atom in the parent compound to which it is connected. 

The solubility behaviour of an unknown compound will serve to classify it into one of the three main divisions, namely, acidic, basic or neutral. This information, supplemented by elemental analysis if deemed necessary, and as noted above cross-correlated with spectroscopic inferences, forms the basis for the subsequent systematic search to identify definitively the functional group or groups present. It cannot be too clearly emphasised that inexperience in spectroscopic interpretation can lead to erroneous conclusions of structure. The value of chemical tests is that they reduce the chance of this happening, furthermore they are frequently easily and quickly performed and provide experience in accurate and reliable observation and reporting. 

The term calix[n]arenes indicates a class of phenolic metacyclophanes derived from the condensation of phenols and aldehydes. The name was coined by Gutsche and derives from the Latin calix because of the vase-like structure that these macrocycles assume when all the aromatic rings are oriented in the same direction.1 The bracketed number indicates the number of aromatic rings and hence defines the size of the macrocycle. To identify the phenol from which the calixarene is derived, the para substituent is designated by name. Thus the cyclic tetramer derived from p-f-butylphenol and formaldehyde is named p-f-butylcalix[4]arene, or with a more systematic but still simplified nomenclature proposed by Gutsche and used in this chapter 5,11,17,23-Te trakis( 1,1 -dimethylethyl)-25,26,27,28-tetrahydroxy calix [4] arene, 1 (Scheme 7.1). The systematic name reported by Chemical Abstracts is pentacyclo[19.3.1.13,7.19 13.115 19]octacosa-l (25),3,5,7(28),9,11,13(27),15,17, 19(26), 21,23-dodecaene-25,26,27,28-tetrol-5,l l,17,23-tetrakis(l, 1 -dimethylethyl). 

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