Direct Alkoxylation Of Palm Stearin In One Step Process

Natural fats and oil are worldwide attentioned as green renewable resource. In addition to being afforded for human consumption, the large number of oils and fats are used as chemical raw materials which are widely used in various industrial fields such as medicine, food, paint and industry surfactants. The one-step oxyalkylation reaction of palm stearin was studied in the basis of Al-Mg-based composite catalyst in this paper. The Screening of catalyst and the exploration of technology conditions were investigated. Palm stearin was modified by chemical method, physical mixing method and biological enzymatic method so that the melting point of palm stearin was lowered.The experimental conclusions were displayed as following:(1) Five types of catalysts were prepared for the ethoxylation reaction of palm stearin. The highest catalytic activity of Al/Mg composites [Al/(Al+Mg)=0.60] in response was 0.252 g EO/g Cat/min. The ethoxylation reaction of palm stearin and EO accompanied by catalyst was proved by FT-IR and ESI-MS. The occurrence of ethoxylation reaction was confirmed by saponification value products test and emulsification properties test. The better temperature of ethoxylation reaction was chose at 160-170 oC through reaction process research. It was found that petroleum ether (boiling point range 90-120 oC) can significantly improve the reaction activity. The catalytic activity in response was cut down by increasing early system pressure.(2) Several types of catalyst were prepared in the propoxylation reaction of palm stearin. The highest catalytic activity of Al/Mg composites[Al/(Al+Mg)=0.50]in propoxylation reaction was detected at 0.144g PO/g Cat/min. The propoxylation reaction between palm stearin and PO accompanied by catalyst was confirmed by FT-IR analysis, ESI-MS analysis, saponification value test and the emulsifying properties test. The better temperature and the eligible pressure were determined at 160-165 oC and 0.3 MPa-0.4 Mpa differently by the reaction conditions study. The better usage amount of catalyst was m (cat): m (palm stearin) = 0.01:1. It was found that the reactivity was gradually reduced when raw materials in the molar ratio n (PO): n (palm stearin) was changed from 0.5 to 2.0 in the process. The propoxylation reaction of palm stearin being a step by step addition reaction was proved.(3) The melting point of palm stearin was lowered by chemical modification, physical modification and biological enzyme modification methods. The melting point of the product of ethoxylation was lowered to 19.8 oC When the molar ratio of palm stearin and ethylene oxide was 6.0 in the chemical method. The melting point of the product of propoxylation was dropped to 39.5 oC when the molar ratio of palm stear and propylene oxide was 3.0 in the chemical method. The lowest melting point of mixed samples was reduced to 31.0 oC when the mass ratio of aether and palm stearin was 1:1 in the exploration of the physical mixing method. However, it was found that mixed with a large number of low boiling point impurities could make the separation and purification process difficult. It was proved that four types of lipase reacting with palm stearin was not significantly lower the melting point of palm stearin in the initial biological enzymatic method.