naphthenen.

1842 T. Graham Elements Chem. iii. iii. 846 The liquid compounds are hydrocarbons, which these chemists name naphtha, naphtene, and naphtol.

1849 J. Craig New Universal Dict. at Naphtha Native naphtha is composed of three liquids, namely—naphtha.., naphthene.., and napthole.

1854 R. D. Thomson Cycl. Chem. 378 Naphthene. C₁₆H₁₆. That portion of mineral naphtha which comes over second in distillation.

1857 W. A. Miller Elements Chem. III. 581 Pelletier and Walter describe three components of naphtha; one, which is termed naphtha, boils at about 190°; the second, termed naphthene (C₁₆H₁₆), boils at 239°; and the third, naphthole, at 374°.

1884 Jrnl. Chem. Soc. 46 1276 Hydrocarbons of the C_nH_2n series, called by the authors naphthenes, constitute the principal part of Caucasian petroleum.

1913 Science 9 May 713/2 The identity of the naphtenes first discovered by Markownikow in Russian petroleum..is fully set forth.

1921 J. S. Chamberlain Textbk. Org. Chem. 38 The saturated cyclic hydrocarbons known as naphthenes are characteristic of Russian (Baku) petroleum and are also found in that from Galicia.

1951 C. R. Noller Chem. Org. Compounds xxxix. 759 The saturated alicyclic hydrocarbons frequently are called cycloparaffins or cyclanes although petroleum technologists usually call them naphthenes because cyclopentane..and cyclohexane..and their homologs have been isolated from the naphtha fraction of petroleum.

1964 N. G. Clark Mod. Org. Chem. v. 78 The naphthenes (a term used in the petroleum industry for the cyclic paraffins) are mainly cyclopentane and cyclohexane, and their simple derivatives.

1993 Toxicol. & Industr. Health 9 1047 Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation.