Study On Green Synthesis And Properties Of Octyl Phosphate

As a kind of essential surfactant,there are two main routes of trioctyl phosphate for the industrial production at present.Trioctyl phosphate could be prepared with the esterification reaction of octanol and phosphorus pentoxide which is used as the raw material.But it's difficult to separate and purify trioctyl phosphate from the mixture which results in low recovery and low purity.There is another reaction in which phosphorus oxychloride or phosphorus trichloride as raw material occur esterification reaction with octanol.The product of the reaction is mixture of octyl ester,dioctyl ester or trioctyl ester.The complicated reaction route results in many side reactions and generates hydrogen chloride which has strong causticity.Therefore,there is high cost of production and environmental protection problem in the reaction method.In this study,isooctyl phosphate was prepared by green synthetic route,and monoisooctyl phosphate,diisooctyl phosphate and triisooctyl phosphate were prepared which are according to the industrial purity requirements.Triethyl phosphate and isooctyl alcohol were used as raw materials for the synthesis of triisooctyl phosphate by transesterification under the action of basic catalyst.Diisooctyl phosphate was synthesized from triisooctyl phosphate by hydrolysis reaction with a phase transfer catalyst.Monoiso-octyl phosphate was synthesized from phosphorus pentoxide by esterification reaction with iso-octyl alcohol after partial hydrolysis of phosphorus pentoxide.The synthesis method of three isooctyl phosphates provided several advantages such as environmental friendliness,simple and controllable process,high yield and purity,which indicated it had high theoretical and application significance.With homogeneous K alkali as catalyst,the suitable operating condition for the synthesis of phosphate of diisooctyl by ester exchange reaction using triethyl phosphate and isooctyl alcohol was as follow: the mole ratio of triethyl phosphate and isooctyl alcohol was 1:4.5,the dosage of catalyst was 5%,the reaction temperature was 160?,reaction time was 4h.Under these conditions,the conversion rate of triethyl phosphate was above 88%,and the yield of triisooctyl phosphate was over 85%.When the heterogeneous load activated carbon and potassium hydroxide were used as catalyst,the ideal operating condition of the ester exchange reaction was: the mole ratio of triethyl phosphate and isooctyl alcoho was 1:4.5,the catalyst dosage was 5%,the reaction temperature was 140?,the reaction time was 6h.The result showed that the conversion rate of triethyl phosphate was more than 91%,the ester yield of three isooctyl phosphate was above 87%.After separation and purification,the purity of triisooctyl phosphate reached above 96%.The process condition for synthesis of diisooctyl phosphate by phase transfer catalyst and triisooctyl phosphate was as follows: the molar ratio of triisooctyl phosphate to sodium hydroxide was 1:1.1,the amount of catalyst was 4%,and the hydrolysis reaction temperature was 100? and the hydrolysis reaction time was 4h.At this time,the yield of diisooctyl phosphate was more than 94% and the purity was 98%.In an organic solvent,partial hydrolysis of phosphorus pentoxide was carried out directly after esterification with isooctanol,and the reaction product was hydrolyzed to synthesize monoisooctyl phosphate.Suitable operating condition was: The molar ratio of phosphorus pentoxide,water and isooctanol was 1:1:3,the esterification reaction temperature was 70?,the esterification reaction time was 3h,the reactant hydrolysis temperature was 80?,and the hydrolysis time was 2h.The purity of monoisooctyl phosphate was over 98%.