Study of Foaming Properties and Effect of the Isomeric Distribution of Some Anionic Surfactants

Abstract Using different reaction conditions of photosulfochlorination of n-dodecane, two samples of anionic surfactants of sulfonate type are obtained. Their micellar behavior has been already reported and the relationship between their isomeric distribution and their chemical structures and micellar behaviors have been more thoroughly explored. In this investigation, we screened the foaming properties (foaming power and foam stability) by a standardized method very similar to the Ross-Miles foaming tests to identify which surfactants are suitable for applications requiring high foaming, or, alternatively, low foaming. The results obtained for the synthesized surfactants are compared to those obtained for an industrial sample of secondary alkanesulfonate (Hostapur 60) and to those of a commercial sample of sodium dodecylsulfate used as reference for anionic surfactants. The foam formation and foam stability of aqueous solutions of the two samples of dodecanesulfonate are compared as a function of their isomeric distribution. These compounds show good foaming power characterized in most cases by metastable or dry foams. The highest foaming power is obtained for the sample rich in primary isomers which also produces foam with a relatively high stability. For the sample rich in secondary isomers we observe under fixed conditions a comparable initial foam height but the foam stability turns out to be low. This property is interesting for applications requiring low foaming properties such as dishwashing liquid for machines. The best results are observed near and above the critical micellar concentrations and at 25°C for both the samples

Identification of parameters W0 , n , and D of the Dubinin�Radushkevich equation

This paper considers a cooling system for a thermal engine using heat from exhaust gas. This system uses a physical adsorption process of solid�gas (active carbon and ammonia). An adsorber tubular element of real scale is submitted to heat flux by electrical air heating, simulating exhaust gas. Temperatures and adsorbed mass are measured. Desorption and adsorption phenomena are described by the Dubinin�Radushkevich model equation, m = W0 [rgr] ( T ) exp[- D ( T? ln ( Ps ( T )/ P )) n ], where W0 , n , and D are parameters characterising the adsorbent�adsorbate couple. These three parameters can be identified from a simple mite method (using data and models) characterising the adsorbent�adsorbate couple chose

Biosurfactants Production from Low Cost Substrate and Degradation of Diesel Oil by a Rhodococcus Strain

The ability of a Rhodococcus strain to produce surface-active agents from residual sunflower frying oil (RSFO) has been screened in batch cultures. During cultivation with RSFO at the concentration 3% (vol/vol), the strain has synthesized extra-cellular compounds which increase the E24 emulsion index of the culture medium up to 63%. In their crude form, these substances lower the surface tension of water until 31.9 mN m-1. The exponential growth with RSFO as the sole carbon source has developed at a specific growth rate μ = 0.55 d-1. The critical micelle concentration of the crude product reached the value 287 mg L-1 (γCMC = 31.9 mN m-1). After methylesterification, the lipid fraction of biosurfactants has been analyzed by GC-MS in EI, which reveals the presence of fatty acid methyl esters. The microorganism was also cultivated with the diesel oil as the sole carbon source at the concentration 1% (vol/vol): the active growth phase has developed at rate μ = 0.02 d-1, without production of emulsifying substance: the microorganism seems to develop different modes of substrate uptake, according to the nature of the carbon source. The potential use of surface-active agents synthesized on RSFO by Rhodococcus erythropolis 16 LM.USTHB is in the oil industry with minimum purity specification, so that crude preparation could be used, at low cost, in clean-up of hydrocarbons contaminated sites and for enhanced oil recovery

Simultaneous Gas-chromatographic Analysis of Heptyl Chloride Heptanesulphonyl Chloride Isomeric Mixtures

Gas chromatographic analyses of several sulphonyl chlorides were performed without derivatization. Optimized conditions for this analysis were selected and the results controlled by gas chromatography-mass spectrometry. The results obtained were compared with data reported for gas chromatography using derivatization. This method was extended to the simultaneous analysis of isomeric mixtures of n-heptyl chlorides and n-heptanesulphonyl chlorides obtained by the photochemical sulphochlorination of n-heptane