Synthetic Technology Study Of Senior Aliphatic Primary Amines

Senior aliphatic amines can be referred to as aliphatic amine, it is an organicamine compound with a carbon chain length in the range of8to22. It can notonly be used for the synthesis of surface active agent, but also be directly used aslubricant, thickener, flotation agent, hydrophobic agent. Because of the complexsynthesis processes, low purity, it is great significant to study the synthesis.In this paper, the synthesis method of the existing aliphatic amines wasstudied systematically, we compared many synthetic routes from the literature.Taking n-bromodecane as an example, study the possibility of Gabriel synthsis ofsenior aliphatic amines, the results showed that total synthetic yield ofn-decylamine is relatively low to37.83%.Based on the existing literature, we designed a technology roadmap, whichwas suitable for industrial production and with a readily available raw materials,mild reaction conditions, lower production costs. The raw material of this routewas alkyl bromide, sodium azide, sodium metal, n-butanol, methanol, a series ofreaction intermediates and target were characterized by IR and1HNMR. Theresults showed that the total yield was up to82%to85%.The concrete work included several aspects: the influence of azide materialratio, solvent type and volume on the conversion rate of bromoalkanes, theinfluence of the reaction temperature on the time of azide, the influence of thereductant metal species, the ratio of raw materials, solvents and reductiontemperature on the the synthesis reaction of the primary amine. The resultsshowed that:1. We synthesised azide alkyl that used the alkyl bromide and sodium azideas raw materials. Meanwhile, we optimized the reaction conditions, the resultswere as follows: Molar-ratio of alkyl bromide and sodium azide was1:1.5, the solvent was methanol, the reaction was refluxed. The yield was monitored by1HNMR, azido alkoxy yield of carbon atoms from8to18was up92.7%even to93.5%. Yield was greatly improved compared to42%of azide in n-decane in theliterature. Compared to N,N-dimethylformamide used in the literature, thetreatment after the reaction was more simple.2. To sodium/n-butanol-reduction as a reduction system, the azide alkylwas reduced to the corresponding primary amine, and we optimized the reactionconditions, the optimum reaction conditions were as follows: Molar-ratio of azidealkyl and metallic sodium were1:3.5, n-butanol was the solvent, the temperaturedid not passed85℃. The yie ld was monitored by IR, positive primary amineyield which carbon atoms were from8to18was up to92%-93.4%. The aftertreatment was more simple which compared to magnesium/methanol system fromthe literature.