Petroleum sulfonates specifications

White oils are prepared by drastic further treatment of lubricant stocks. In the older process the appropriate stock was subjected to successive treatments with sulfuric acid until the refined oil met the desired specifications. Acid-treatment is still used to refine white oils because the other products of the process, mahogany petroleum sulfonic acids, are valuable and useful in their own right. The modern process for making white oils utilizes a severe double hydrogenation followed by clay bleaching. 

The adsorption from microemulsion of two petroleum sulfonates, PDM-334 and TRS 10-410, on Berea sand/montmorillonite clay adsorbents has been studied to determine 1) the effect of microemulsion composition, specifically its relative oil and brine content, on sulfonate adsorption 2) the effect of adsorption on the microemulsion composition and interfacial tension behavior. Whereas the degree of sulfonate adsorption can be determined by conventional methods (e.g. UV spectroscopy), one must utilize a microemulsion property which is a sensitive function of the relative oil and brine content of the microemulsion in order to determine the adsorption-induced changes in the microemulsion composition. This can be accomplished by the use of the microemulsion specific refraction. 

The objective of the present work is to determine the static adsorption of petroleum sulfonates from microemulsions on representative reservoir solids and to define the effect of microemulsion composition, specifically its relative oil and brine content, on sulfonate adsorption. It is also of interest to determine the effect of adsorption on the microemulsion oil and brine content because of the relationship between microemulsion composition and interfacial behavior. Consequently, the adsorption of a given petroleum sulfonate was determined from a series of microemulsions where each microemulsion contained different volume fractions of the same oil and brine. The difference in microemulsion composition within such a series was effected either by using a different cosurfactant in each microemulsion or by changing the total surfactant/cosurfactant concentration. The adsorbent was carefully reproduced in each experiment in terms of sand/clay composition and total surface area. All experiments within a series were therefore carried out at constant temperature, pressure, adsorbent composition and total surface area. 

Another study suggested the use of other sulfonating agents such as p-toluensulfonic acid (p-TSA). Although the material seems to be very efficient catal3ftically, its activity looks to be more related to the residues of p-TSA on the material than to attached sulfonic groups, because the analysis of the sample showed bands in the infrared spectra associated specifically to p-TSA. This would be likely to leach into solution. Another drawback of this approach is related to the manner of preparing p-TSA, as precursors involved will be toluene (petroleum base material) and sulfuric acid. 

There are a number of reviews available for surfactants in specific industries [S7], and for specific surfactant classes. References [SJ-90] discuss methods for the determination of anionic surfactants, which are probably the most commonly encountered in the petroleum industry. Most of these latter methods are applicable only to the determination of sulfate- and sulfonate-functional surfactants. Probably the most common analysis method for anionic surfactants is Epton s two-phase titration method [9J, 92] or one of its variations [93, 94], Related, single-phase titrations can be performed and monitored by either surface tension [95] or surfactant-sensitive electrode [84, 85, 96-98] measurements. Grons-veld and Faber [99] discuss adaptation of the titration method to oleic phase samples. 

As has been established in other chapters of this book, the reasons behind the search for bio-based alternatives to petroleum-based surfactants can be summarized in one word - sustainability. However, there are different ways to produce bio-based surfactants, all of which have different degrees of sustainability. As an example, soaps - alkaline salts of fatty acids - can be considered bio-based surfactants, as they are derived from the saponification of triglycerides obtained from plants and animals. Methyl ester sulfonates are obtained from fatty acid methyl esters (FAMEs) which in turn are also obtained from triglycerides found in plants and animal tissues. Lecithin, lysolectihins and other phospholipids can also be extracted from plant and animal tissue. As will be explained in the next sections, bio-based surfactants can also be secreted by microbial cultures fed with specific substrates. 

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