Identification of some naturally occurring alkylthiphenes in wilmington, calif., crude oil by use of a series of gas—liquid chromatography stationary phases
✍ Scribed by H.J. Coleman; C.J. Thompson; R.L. Hopkins; H.T. Rall
- Publisher
- Elsevier Science
- Year
- 1965
- Tongue
- English
- Weight
- 977 KB
- Volume
- 20
- Category
- Article
- ISSN
- 1873-3778
No coin nor oath required. For personal study only.
✦ Synopsis
INTRODUCTIOX
Knowledge
of the natural occurrence of allcylthiophenes in petroleum is important, not only to the practical chemist interested in the separation, identification, and removal of sulfur compounds from petroleum distillates, but also to the fundamental chemist and geologist concerned with the origin of petroleum.
Early researchers1 2 reported the presence of thiophene and some of its alkyl homologs in products of pyrolytic origin such as coal tars, shale oils, and "cracked" petroleum. BLRCH~ in 1953 described the identification of four alkylthiophenes in an acid extract of an Iranian distillate. In 1956 THOMPSON ct ~2." identified thiophene and z-methylthiophene in a specially prepared, unpyrolyzed distillate. The use of gas chromatography as a separation tool for thiophene and its homologs"-* resulted in additional identification.& 1". This paper describes in detail the systematic liquid-solid-and gas-liquidchromatographic procedures used for the concentration and identification of eight allcylthiophenes in a Wilmington, Calif,, crude oil distillate having a boiling range of III0 to qo", and presents quantitative data for each of the identificcl thiophenes. EXPERIMENTAL A major obstacle in separating and identifying any particular sulfur compound from a crude oil is the minute quantity usually present. The processing and sulfurcompound concentrating steps applied to the crude oil, preparatory to separating and identifying individual alkylthiophenes, included isothermal distillation, vacuum fractionation, and liquid-solid chromatography. Isotlzermzl distillation. Fig. I shows the sequence of steps used in processing 165,37 kg _(.approximately 50 gallons) of Wilmington,
Calif., crude oil to yield the concentrates for sulfur-compound identifications. The initial step consisted of passing the crude oil through an all-glass falling film flash still, heated by steam to 100~. With a crude oil input of 30 to 40 ml per min, a sample contact time on the rotating glass drum of less than 30 set, and a helium sweep rate of g 1 per min, this isothermal still, at atmospheric pressure, produced a distillate containing all the material