Isolation of sulfur compounds

STRAUSZ ET AL. Isolation of Sulfur Compounds from Petroleum... 

Strausz, O.P. Payzant, J.D. Lown, E.M. Isolation of Sulfur Compounds From Petroleums , this volume. 

Thiophene and methylthiophenes have been found in virgin petroleum. 3,4,5-Trimethyl-2-methylthiothiophene has been isolated from a concentrate of sulfur compounds obtained in the refining of Middle East kerosene. ... 

Although neither the enzymes, nor the genes were identified or isolated by the time the patents were filed, their use was claimed as part of one of the patents [239], It should be noted that the type of sulfur compounds (aromatics) to be removed were predicted and a divisional patent was obtained [238], In the subsequent patent, [241] the type of sulfur compounds to be removed were mentioned, and additionally the pre- or post-BDS stage was discerned to be a mild-HDS process (MDS). 

The isolation of pure compounds from mixed sulfur-selenium melts was further questioned by mass spectroscopic studies The existence of SeS., Se Sg,... 

One or two hexachlorobutadiene metabolites appear to cause some of the compound-induced renal damage (see Section 2.3.5) and are more toxic than the parent compound, causing comparable lesions in the kidneys at lower doses. These active thioacylating metabolites are capable of modifying DNA, as indicated by the isolation of sulfur-containing nucleides from hydrolyzed DNA from renal cells exposed to the hexachlorobutadiene cysteine derivative (Vamvakas et al. 1988b). 

A summary of the work on the identification of sulfur compounds in crude oils has been given recently by Ball, Rail, Waddington, and Smith (31), who list the sulfur compounds isolated from petroleum by earlier investigators and, in addition, give several new compounds which have recently been isolated from a Wasson, Tex., crude petroleum by the API Research Project 48. Birch and Norris (5) isolated a substantial number of the thiol (mercaptan) type of sulfur compounds from an Iranian crude petroleum. 

In addition to the sulfur compounds listed above, hydrogen sulfide has been found in many crude petroleums. Elemental sulfur has been definitely found in several crude petroleums by API Research Project 48 (23). Although Birch and Norris (5) isolated several disulfides from the spent caustic used in treating gasoline from Iranian petroleum, these compounds may have resulted from the oxidation of the thiols and their presence in the original petroleum is regarded as doubtful. Other types of sulfur compounds, such as thiophenes and aromatic thiols, have been identified in cracked petroleum products, but the presence of such compounds in naturally occurring petroleums has not yet been established. 

The synthesis of the heteroarylcarboxylic acid chlorides is fraught with difficulties. When isolated, the acid chlorides are generally unstable and readily produce bisheteroaryl ketones (see Section 3.05.1.2.9). Using standard preparative procedures the increase in the acidity of the reaction medium can cause polymerization, whilst the addition of a base can result in the formation of compounds of the type (403) and (404). Attempts to prepare indole-2 -carboxylic acid chloride using thionyl chloride result in the isolation of sulfur-containing derivatives, which arise from electrophilic attack at the 3-position (64JOC178). 

The first section contains overview and introductory material, some historical background, summaries of the present state of knowledge, and other general topics applicable to all fossil fuel These include environmental consequences of fossil fuel combustion, polysulfide chemistry, microbial metabolism of sulfur compounds, and a review of methods for isolating sulfur compounds from petroleum. 

Hodge et al. (45) discussed mechanisms for formation of methyl furanones and related substances from Amadori compounds. They have been produced by heating D-ribose and D-ribose phosphate with ammonia (46 47). Hicks and Feather (48) demonstrated that the Amadori compound 1-benzylamino-l-deoxy-D-threo-pentulose dehydrates to 4-hy-droxy-5-methyl-3(2H)-furanone and it has also been identified as a degradation product of L-ascorbic acid. This compound is believed to be formed from ribose-5-phosphate, and gained prominence when it was isolated from beef by Tonsbeck et al. (49). It became more apparent as a precursor of meat flavor when Van den Ouweland and Peer (50) reacted it and its thio analog with HaS to produce a number of sulfur compounds, some of which had meaty odors. 

By optimizing the reaction conditions, the formation of the Ar2S can be improved from moderate to good yields (64—83%) [17]. Different chemical transformations are also possible for ArS ions formed in the SRN1 reaction without isolation, and with this strategy a variety of sulfur compounds have been synthesized (Scheme 10.29) [46],... 

Carbene adducts of a range of sulfur compounds have also been isolated. Carbene (1) (R = i-Pr, R = Me) reacts with sulfur dichloride or thionyl chloride to yield the hyperva-lent sulfur derivatives (118) and (119). Similarly, reaction of carbene (2) (R = r-Bu) with SO2 led to the formation of the 1 1 adduct (2)-SO2 (120). In contrast, reaction of carbene (1) (R = i-Pr, R = Me) with SO2CI2 affords the 2-chloro-l,3-diisopropyl-4,5-dimethylimidazohumchlorosul-fite salt (121). A carbene adduct of SO3 (122) can then be isolated through hydrolysis of (121) in the presence of cyanide. 

Physical Separation of Sulfur Compounds. In order to make several types of determinations feasible it is frequently necessary to isolate or to concentrate the sulfur compounds. Various means such as distillation, extraction, and absorption have been employed to affect the separation because these operations are closely related to those processes which may be employed to segregate sulfur compounds on a commercial scale. The discussion of these topics will be undertaken in the section. Processes for Segregating Sulfur Compounds. 

Reactions of diaryliodonium salts with various organochalcogen anions led to the arylchalcogen derivatives. (Table 5.7) The anions of sulfur compounds afford generally the 5-aryl derivatives. Sometimes the intermediate iodanes can be isolated. Examples are the reaction of dithiocarbamate and xanthate salts with diaryliodonium. Upon heating, the dithiocarbamate derived iodane afforded the aryldithiocarbamates.133 Thermal decomposition of the xanthate derived iodanes gave mixtures of arylxanthates and diaryldisulfides. ... 

The first to be used was coal gas. Composed mostly of hydrogen, carbon monoxide, and hydrocarbons, coal gas can be explosive and toxic, but it contains traces of sulfur compounds (natural or added) that give it the rotten-egg smell that indicates a gas leak. This gas was used for illuminating houses and streets beginning in the early 1800s, and it was the gas Bunsen used to fuel his Bunsen burner for spectroscopic studies. Coal tar found its first use as a wood preservative, but coal tar is a complex mixture of aromatic organic compounds, including benzene, toluene, xylenes, naphthalene, phenols, and anthracene as more compounds were isolated from its matrix, identified, and studied, coal tar became the basis for an entirely new chemistry. 

Several methods have been employed (20) in the extraction of flavor volatiles from their chemical and physical bonds in the complex muscle matrix. These methods include steam distillation, solvent extraction, headspace analysis and supercritical fluid extraction. Each method had specific advantages and shortcomings when used in the isolation of numerous compound types such as carbonyls, sulfur-containing compounds such as thiols and thiazoles, pyrazines, furans, and pyrroles (27, 22). The mechanisms responsible for the formation of these flavor volatiles have been proposed and developed based on such experimentation (25, 24). 

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