Preparation Of Tributyl Phosphate,bis(2-ethylhexyl) Phosphate And Trisoioctyl Phosphate From Sodium Alkoxide

Tributyl phosphate,bis(2-ethylhexyl)phosphate and trisoioctyl phosphate are important organic phosphate products.As the common extractant and flame retardant,plasticizer,they are widely used in solvent extraction,hydrometallurgy,plastic and rubber additives and other various fields of chemical production.In addition,they have make roles in the treatment of phenol wastewater,the production of hydrogen peroxide by anthraquinone process.Traditional production of phosphate is direct esterification of the corresponding alcohols with phosphorus oxychloride.In order to lower the byproducts,hydrogen chloride generated in reaction has to be removed by reduced pressure,and the reaction is generally carried out at lower temperature and vacuum,this results in high material costs,low product yields and high COD value of waste water.Therefore,it is of great research significance to improve the synthetic route reasonably.In this paper,a synthetic method is presented to prepare phosphates from sodium alkoxides,i.e.sodium alkoxide is prepared from alcohol and aqueous sodium hydroxide and esterification of the sodium alkoxide and phosphorus oxychloride gives corresponding phosphates.The method has certain practical value with the advantages of no vacuum,high reactivity,no hydrogen chloride,and also no pollution for the environment.The feasibility of preparing the above three phosphates from sodium alkoxide was studied.The experimental results showed that this synthetic method worked well for tributyl phosphate,bis(2-ethylhexyl)phosphate and trisoioctyl phosphate.The influence of key factors,such as dehydration method,reaction conditions and work-up methods etc.,was investigated through single-factor experiment.On the basis,we got suitable experimental results by optimizing reaction conditions.Preparation of tributyl phosphate: sodium butoxide was synthesized from n-butyl alcohol and aqueous sodium hydroxide with azeotropic dehydration method by fractional distillation,and then reaction of sodium butoxide and phosphorus oxychloride gave tributyl phosphate,by optimization for experiment,the yield could reach 92.8%,the purity of GC detection is 99.5%.Preparation of bis(2-ethylhexyl)phosphate and trisoioctyl phosphate: sodium isooctanoxide was synthesized from isooctyl alcohol and solid sodium hydroxide via azeotropic distillation in toluene.Bis(2-ethylhexyl)phosphate and trisoioctyl phosphate were prepared by reaction of sodium isooctanoxide and phosphorus oxychloride under appropriate conditions.The result showed that the yield of bis(2-ethylhexyl)phosphate was 87.7% with a purity of 95.2% and the monoester content was 1.4%,the yield of trisoioctyl phosphate was 90.1% with a purity of 99.5%,achieving the desired results.The recovery methods of unreacted alcohol and washing water in preparation of tributyl phosphate were studied in order to satisfy the requirements of commercial process,this recovery method effectively reduced the production cost and the amount of waste liquors.In this paper,the industrial production of tributyl phosphate was studied based on the optimum conditions obtained in laboratory and satisfied results were gained by adjusting the operating methods.