Research On Elimination And Hydrolysis Of α-chloro Long Chain Fatty Acid

The development and application of fat chemicals have been research hot spots in worldwild. The fatty acid is the main body and core in oil chemistry industry, by simple processing, it can be changed into fatty acid methyl ester, the fat is mellow, fat amine and other base oil chemical products. Take these base oil chemical product as raw material through further chemical processing, variety fine chemical and special-purpose chemical can be obtained, both long chainα,β- unsaturated fatty acid andα-hydroxy fatty acid are fine products in chemical industry, they are widely applied in food, medicine and daily chemistry industry.In this paper, it has been studied that the elimination and hydrolysis ofα-chloro-dodecanoic acid(α-CDA) which is self-made by our laboratory. The main research content is: Investigate some catalyze catalysisingα-CDA to prepare 2-dodecenoic acid, and inspects various factors to effect the yield of 2-dodecenoic acid andα-hydroxy dodecanoic acid(α-HDA).The effect of different catalyze on catalysising the elimination ofα-CDA to synthesis 2-dodecenoic acid were investigated. The catalytic activity of alkali metal, alkali earth metal and hydroxides or carbonates of the alkali metals, alkali earth metals is so weak, their alkalinity is not enough to catalysisα-CDA dehydrochlorogenating, the yield of 2-dodecenoic acid is very low. The tertiary butyl alcohol potassium(t-BuOK) had good catalytic activity on preparing 2-dodecenoic acid, but its alkalinity is so strong that it forcedα-CDA dechlorogenating into the lauric acid partly, when reduced its amount, many hydroxy acid were producted.In forward research, it had been studied that the preparation of 2-dodecenoic acid which can be obtained directly by eliminating of alpha-chlorododecanoic acid(α-CDA) when took potassium hydroxide(KOH) as dehydrohalogenating reagent, replacedα-bromo acid andα-iodo acid which was taken as raw material in the conventional routes. This craft was simple and the yield was enhanced. It had been found that a by-product(α-ethoxyl substituted fatty acid) had been avoided when took the glycol dimethyl ether as solvent. What′s more, after craft optimization, the dosage of potassium iodide had been reduced from n(KI):n(α-halo fatty acid)=1.5 to n(KI):n(α-chloro dodecanoic acid)=0.35, reduced production cost greatly and maked this route to have industrialization prospect. A yield of 52.0% of 2-dodecenoic acid can be obtained in 9 hours under the following optimized conditions: n(KI):n(α-CDA)=0.35, n(KOH):n(α-CDA)=3.8, reaction temperature at 84℃. The product was purified by petrolum crystallization and cupric acetate extraction, finaly the purity of 2-dodecenoic acid achieved 72.2%.It also had been studied that the prosess of synthesisα-HDA which can be obtained directly by hydrolysis ofα-CDA under weak alkaline situnation. Highe yield can be obtained by taking Ca(OH)2 as hydrolisis reagent, the yield was up to 80.2%.What′s more, some means have been tried to separate theα-HDA from raw materialsα-CDA. Experimental result indicated that using petroleum ether as solvent to recrystal, the purity ofα-HDA can reached 99.4%.