No. 1, Volume 1 
July 1997

  Dr. Claff
A chemist-turned-translator, Dr. Claff earned his B.S. and Ph.D. degrees in Organic Chemistry at M.I.T. in 1950 and 1953. His academic and industrial research experience included the fields of organosodium chemistry, synthetic rubber, leather tanning and finishing, acrylic and vinyl polymerization, adhesives for coated abrasives, and flexographic printing inks. His career later evolved into corporate administration and management in metalworking, heart-lung machines, biological instrumentation, printing, personnel administration, and paper box manufacturing. His exposure to such diverse disciplines has been a valuable resource in his career as a freelance technical translator since 1974.
   Dr. Claff and his wife Eleanor make their home in Brockton, Massachusetts, with the Maine coon cats, DownE and Baxter.
  Dr. Claff can be reached at

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Translation Journal

A Translator’s Guide to Organic Chemical Nomenclature


by Chester E. Claff, Jr., Ph. D.
Download the zipped version of the first installments of this series, originally published in the Sci-Tech Translation Journal, of the American Translators Association. The file is approximately 87 KB.
Introductory Remarks
Parts I to VII of this series, which began with the assumption that the reader has no knowledge of chemistry, appeared in the seven consecutive issues of the Sci-Tech Translation Journal of the ATA from October 1994 to July 1996. Some knowledge of organic chemistry is recommended for those starting with this Part VIII.
   We will now pick up the thread where we left it a year ago, when we discussed organic oxygen compounds, specifically alcohols and ethers.

V. Organic Oxygen Compounds
Glycols, Glycol Ethers, and Polyhydric Alcohols

We have seen that alcohols and ethers can be considered to be derivatives of water, in the sense that ROH and ROR' can be obtained by replacing the hydrogen atoms of water (HOH) with alkyl groups R or R'. They can also be viewed in the other direction, as hydrocarbons whose hydrogen atoms have been replaced by hydroxyl or alkoxyl radicals HO or RO. With this approach, ethyl alcohol would be formed by the (hypothetical) reaction:

CH3CH2 + OH --> CH3CH2OH

Continuing this hypothetical procedure one step further, we obtain:


The product is a diol, a dihydroxy compound, otherwise called a glycol. It can be called 1,2-ethanediol, 1,2-dihydroxyethane, or most commonly ethylene glycol. Recall that CH2=CH2 is ethylene and ClCH2CH2Cl is ethylene chloride; CH2CH2 is the ethylene radical or the ethylene group. The term “glycol” is preferably reserved for only two compounds, ethylene glycol and propylene glycol (1,2-dihydroxypropane or 1,2-propanediol), but other usages will occasionally be encountered, such as butylene glycol (1,2-, 1,3-, or 2,3-butanediol).

Glycol Ethers
While the subject of glycol ethers may seem too narrow to be addressed in a broad treatment of organic nomenclature, their ubiquitousness in the industrial sector, their commonly used trade names, and their odd treatment in German nomenclature, prompt a careful look. German-to-English translation errors abound in this tiny niche.
   Ethylene glycol can form ethers with alkyl groups in the same way as ethyl alcohol:

Ethylene glycol monomethyl ether

Although an article on this subject was published in the Sci-Tech Newsletter in 1990, the table from that paper bears repeating to show the possible pitfalls when translating the German names of some members of this family of compounds:

   Table 10. Representative Glycols, Polyglycols, and Their Ethers  

          Chemical Formula          English Name(s)German Name(s)
HOCH2CH2OHEthylene glycolÄthylenglykol; Glykol
H(OCH2CH2)nOHPolyethylene glycol; poly(ethylene glycol)Polyglykol; Polyäthylenglykol
CH3OCH2CH2OHEthylene glycol monomethyl ether; 2-methoxyethanol; Methyl Cellosolve®Methylglykol
C2H5OCH2CH2OHEthylene glycol monoethyl ether; 2-ethoxyethanol; Cellosolve®Äthylglykol
CH3OCH2CH2OCH3Ethylene glycol dimethyl ether; 1,2-dimethoxyethane; monoglymeDimethylglykol
C2H5OCH2CH2OC2H5Ethylene glycol diethyl ether; 1,2-diethoxyethaneDiäthylglykol
HOCH2CH2OCH2CH2OHDiethylene glycolDiglykol; Diäthylenglykol
CH3OCH2CH2OCH2CH2OHDiethylene glycol monomethyl ether; Methyl Carbitol®Methyldiglykol
C2H5OCH2CH2OCH2CH2OHDiethylene glycol monoethyl ether; Carbitol®Äthyldiglykol
CH3(OCH2CH2)2OCH3Diethylene glycol dimethyl ether; diglymeDimethyldiglykol

Polyhydric Alcohols
The most common triol is glycerol (1,2,3-propanetriol or 1,2,3-trihydroxypropane). You will also encounter the name glycerine or glycerin, which is not as acceptable but has become familiar from its derivative nitroglycerin(e) (more properly called glycerol trinitrate). The common name for 1,2,3,4-tetrahydroxybutane is erythritol. The 5-carbon tetrol tetra(hydroxymethyl)methane is called pentaerythritol; pentaerythritol tetranitrate (PETN) is a powerful explosive. Specific optical isomers (to be defined later) of the straight-chained 5-carbon and 6-carbon polyols analogous to glycerol are arabitol and mannitol. Polyhydric alcohols (polyols) can also form ethers and polyethers, in the same way as diols (glycols).

Cyclic Ethers
Two molecules of an alcohol in reality form an ether by losing a molecule of water between them; one molecule loses a hydrogen atom H and the other loses a hydroxy group OH:

RO-H + HO-R --> ROR + HOH

Since this is the case, it is possible for a molecule with two hydroxyls on different carbon atoms to form internal ethers:

HOCH2CH2OH --> Ethylene Oxide + H2O

The product in this case is called ethylene oxide, and is an important monomer and reactive intermediate. A catalyst RXM (not specified here) can open the ethylene oxide ring, which then adds to itself to form polyethylene glycol (PEG):

RXM + x · Ethylene Oxide --> RX(CH2CH2O)xM

If RXM is an alcohol ROH, the product is an ethoxylated derivative of the alcohol, RO(CH2CH2O)xH. A simple example of this type of derivative, when RXM is CH3OH and x = 2, is CH3OCH2CH2OCH2CH2OH, Methyl Carbitol® (see Table 10).
   Ethylene oxide is an epoxy compound, and can also be named 1,2-epoxyethane. Diepoxy compounds are commercially important as components of epoxy adhesives. The simplest diepoxy compound is erythritol anhydride, or 1,2,3,4-diepoxybutane:


Terminological purists will name compounds with 3-membered epoxy rings as derivatives of oxirane, the internationally recognized (IUPAC) name for ethylene oxide.Part IX will continue the discussion of organic compounds of oxygen.

  © Copyright 1997 Gabe Bokor
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Updated 07/10/97