organic chemistry of surfactant:
organic chemistry of surfactant:
(Section 1.7) Presently, about 50% of the surfactants used in the surfactant industry are derived from petrochemical raw materials, and the other 50% are derived from oleochemical raw materials.
Renewable surfactant feedstocks are often perceived as being better for the environment and should therefore be the first choice for environmentally ‘‘friendly’’ products. But is that ‘‘analysis’’ of the situation scientific fact or spiritually pleasing fiction?
From biodegradation, removal by sewage treatment, toxicity, and similar studies indicate that there is little or no measurable difference between surfactants based on petrochemical and renewable raw materials in terms of their direct impact on the environment.
Surfactants may also cause problems at later stages of oil processing. In some cases, especially where the extracted crude is recovered in the presence of a great deal of water, the presence of surfactants produces emulsions or microemulsions that must be broken and the water separated before further processing can occur. Naturally present surface-active materials in the crude plus any added surfactants can produce surprisingly stable emulsion systems. The petroleum engineer dilemma: (1) surfactants are necessary for efficient extraction, (2) but their presence produces difficult problems in subsequent steps.
It is important to develop a high sensitive method of determination for surfactants to study the biodegradability and aquatic toxicity of the surfactants in environment as well as its influence on the physiological process. There are many methods for determining surfactants i.e. absorption spectrophotometry, IR, electricity tension, luminosity, analytical method and HPLC.
It successfully applied to determination of low concentration of cationic surfactants in the domestic sewage and Xian city moat.
Processes such as steam flooding involve injecting high-pressure steam at about 340° C into the oil bearing rock formations. The steam heats the crude oil, reducing its viscosity and applying pressure to force the material through the rock matrix toward recovery wells. Unfortunately, the same changes in the physical characteristics of the crude oil that make it more mobile in the formation also render it more susceptible to capillary phenomena that can cause the oil mass to break up within the pores of the rocks and leave inaccessible pockets of oil droplets. In such processes, surfactants are used to alter the wetting characteristics of the oil–rock–steam interfaces to improve the chances of successful recovery. Those surfactants must be stable under the conditions of use such as high temperatures and pressures and extremes of pH.
(1) Proper wetting of oil-bearing formations, (2) microemulsion formation and solubilization properties, (3) ease of emulsion breaking after oil recovery.
The properties and applications of surfactants are determined by the balance between the lyophilic (‘‘solvent-loving’’ and lyophobic (‘‘solvent-hating’’) portions of the molecules. (There are also water-loving hydrophilic, water-hating hydrophobic, fat-loving lipophilic, and fat-hating lipophobic).
For that reason, such characteristics as solubility, surface tension reducing capability, critical micelle concentration (cmc), detergency power, wetting control, and foaming capacity may make a given surfactant perform well in some applications and less well in others. The ‘‘univer-
sal’’ surfactant that meets all the varied needs of surfactant applications has yet to emerge from the industrial or academic laboratory.
Spectrophotometric Determination of Cationic and Anionic Surfactants with Anionic Dyes in the Presence of Nonionic Surfactants, Part I: A General Aspect
Shoji Motomizu, Mitsuko Oshima, and Yasuhiro Hosoi. Mikrochim Acta 106, 57-66 (1992)
…The addition of alcohols, organic onium ions, anionic surfactants and nonionic surfactants brought about a decrease of the band at wavelengths near 480 nm and an increase of the band at wavelengths near 420 nm. Such a shift toward the shorter wavelengths in spectra was attributed to the change of the micro-environment around the dyes from a polar field to a less polar field…
Dynamic interfacial tension behavior of acidified oil/surfactant-enhanced alkaline systems 1. Experimental studies
Youssef Touhami, Vladimir Hornof, Graham H. Neale. Colloids Surfaces A: Physicochem. Eng. Aspects 132 (1998) 61-74
Colloid and survaces.pdf
Determination of Cationic Surfactant by Laser Thermal Lens Spectrometry
Chinese Chemical Letters Vol. 13, No. 11, pp 1107 – 1110, 2002. Hong Tao YAN*, Ying ZHANG, Yang YAN