stearyl chloride | Sigma-Aldrich
Adipic acid, HOOC(CH2)4COOH, is a white crystalline solid used primarily in the manufacture of nylon-6,6 polyamide. In industry, adipic acid is mainly produced by oxidation of cyclohexane with air and nitric acidfollowing a homogeneous two-step route. However, this process leads to the formation of nitrous oxide, a greenhouse gas that has to be decomposed. The aim of this study was the development of a clean technology at pilot scale in order to obtain and recover pure adipic acid, and the evaluation of its industrial practicability. Adipic acid was synthesized from cyclohexene and hydrogen peroxide in microemulsions with stearyl dimethyl benzyl ammonium chloride as surfactant. The non-polluting catalyst sodium tungstate, which contains no heavy metal, was used and the reaction conducted under mild conditions (85 C, 8 h). Yields of up to 81% were reached at the 0.14 L scale. However at the end of the reaction the catalyst and the surfactant must be separated and recycled for subsequent cycles. The reuse of the reaction media enabled the conversion to be increased up to 92% but a loss of surfactant and/or catalyst through the cycles progressively reduced the yields. Yields at the bench scale (1.4 L) increased during the two first cycles and then decreased to conversions of between 60% and 70%. Globally the yield is a little lower at bench scale. The results obtained show that the synthesis of adipic acid by a heterogeneous one-step oxidation of cyclohexene in the presence of hydrogen peroxide is an attractive route for developing a future green industrial process.
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Dimethyldioctadecylammonium chloride, or; ..
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stearyl trimethyl ammonium chloride | Sigma-Aldrich
The CAS numbers for cetearyl alcohol are 67762-27-0 and 8005-44-5. Cetearyl alcohol is the name that you have to use on an ingredient list but it is usually referred to as cetostearyl alcohol. No safety concerns have ever been raised with this material and it is so easily made that it is a very cost effective material in most applications. The thing to watch out for though is the differences between grades. Because it is a blend of fatty alcohols the distribution of chain lengths can vary a lot from supplier to supplier. Particularly where it is being used as an emulsion stabiliser the more diverse the chain length the better it is. Purer is definitely not better. The chain length distribution will have a big effect on the liquid crystal structure too, so it might well affect how actives are delivered from a formulation. Just because this material is cheap and familiar doesn’t mean a formulator can fail to treat it with respect.
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