Synthesis Of Sorbitan Poly Oleate

Sorbitan esters are kinds of high performance surfactants. They were normally used for lubricating oil, and now they are mainly applied in emulsion after modification. With strong emulsifying ability, the oil can be combined with water tightly through these emulsifiers to form a relatively stable emulsion matrix. A better storage stability and explosive performance of the emulsion explosive made by these emulsifiers are formed. The use of sorbitan esters in emulsion explosives industry have been more and more important in recent years. In this paper, the sorbitan poly oleate was obtained through the method of two-step esterification with sorbitol and poly oleic acid as the raw materials. The influence factors of the reaction were studied. The structure of the product was analyzed by FT-IR and HPLC-MS. Emulsification efficiency, HLB value and other performances were measured and compared with that of Span80 and T154. The main research contents and results were as follows.The poly oleic acid was synthesized with industrial vegetable acid oil as the raw material. The yield of the oleic acid was determined by measuring iodine value. The reaction conditions were optimized with the yield of the oleic acid as evaluation index. The optimum reaction conditions were as follows: protection of nitrogen, activated clay as catalyst, clay to oleic acid mass ratio was 18%, reaction temperature was around 220 ?,reaction time was 7.6 h, antioxidant to poly oleic acid mass ratio was 1%. The yield of the oleic acid was 63.0% under the conditions.In addition, sorbitan poly oleate was synthesized through the two-step method of etherification followed by esterification. The reaction conditions were optimized with the acid value, hydroxyl value and saponification value as evaluation index. The optimum reaction conditions were as follows: protection of nitrogen, sorbitol to poly oleic acid molar ratio was 1:0.8, self-made catalyst to sorbitol mass ratio was 5% in etherification stage, etherification time was 40 minutes, etherification temperature was 165?, the dehydration degree of etherification was 1.4; sodium carbonate as catalyst to total reactants mass ratio was 3% in esterification stage, esterification time was 3 h, esterification temperature was around 210?. Under the optimum reaction conditions, the acid value, hydroxyl value and saponification value were respectively 2.6 mg/g, 149.3 mg/g and 197.2 mg/g. The esterification rate was about 99%.Some basic properties of the new emulsifier sorbitol poly oleate were also studied in this paper. The results indicated that: sorbitol poly oleate has good emulsifying ability and the properties of reducing the interfacial tension of water to oil. All aspects of performance of sorbitan poly oleate are better than that of Span80 and T154.