Study On The Application Of Grafted Glufosinate In The Production Of Waste Solvents

Glufosinate-ammonium is an important herbicide and gets rapid development in recent years. But a variety of solvents are needed during the production process of glufosinate-ammonium. And relevant enterprises are faced with the problem of recycling of a large amount of waste solvents. In this paper, the current production status of glufosinate-ammonium at home and abroad as well as types and treatments of waste solvents during the production process are systematically summarized. Due to the differences in the production process, two kinds of waste solvents are mainly produced after the preliminary processing conducted by the enterprises. They are: waste solvents A (tetrahydrofuran 35.0 wt%, ethyl methyl phosphite 15.0 wt%, phosphorous ether 2.0 wt% and trimethylbenzene 48.0 wt%) and waste solvents B (38.0 wt% tetrahydrofuran, dibromoethane 14.0 wt%, phosphorous ether 4.0 wt%, trimethylbenzene 44.0 wt%). And tetrahydrofuran, ethyl methyl phosphite, dibromoethane, phosphorous ether and trimethylbenzene are important chemical materials, which must be recycled through appropriate technology route to make them cyclic. Meanwhile environmental pressure of the enterprises can be reduced.For waste solvents A, three kinds of technological processes are designed for recovery of tetrahydrofuran, ethyl methyl phosphite, phosphite ester and mixed trimethylbenzene. They are:three towers in series by atmospheric pressure continuous distillation, side discharging distillation followed by continuous distillation and double side discharging continuous distillation. After through the simulation and calculation of Aspen Plus chemical process and taking the purity and yield of products, energy consumption and equipment cost into account, the side discharging distillation followed by continuous distillation is regarded as the best technological process. And the effect of theoretical stage number, feed location, reflux ratio and side withdrawal position parameters on the results of recycling is investigated through the method of single factor experiment combined with orthogonal experiment. On the basis of simulation calculation, the device of the side discharging distillation is designed and the experiment processes are researched. Results show that, under the conditions of optimized process, the purity and the yield of tetrahydrofuran are 99.7% and 99.1%, those of ethyl methyl phosphite are 98.6% and 98.0%, those of phosphite ester are 95.1% and 94.2% and those of trimethylbenzene are 98.1% and 97.5%, which meet the recycling standards of the enterprises.For waste solvents B, three kinds of technological processes are designed for recovery of tetrahydrofuran, dibromoethane, phosphite ester and mixed trimethylbenzene. They are:three towers in series by atmospheric pressure continuous distillation, side discharging distillation followed by extractive distillation and double side discharging distillation. After through the simulation and calculation of Aspen Plus chemical process and taking the purity and yield of products, energy consumption and equipment cost into account, the side discharging distillation followed by extractive distillation is regarded as the best technological process. And the effect of theoretical stage number, raw material feed location, extracting agent feed location, reflux ratio,side withdrawal position and. solvent ratio on the results of recycling is investigated through the method of single factor experiment combined with orthogonal experiment. On the basis of simulation calculation, the device of the side discharging distillation and the extractive distillation are designed and the experiment processes are researched. Results show that, under the conditions of optimized process, the purity and the yield of tetrahydrofuran are 99.0% and 98.6%, those of dibromoethane are 96.5% and 89.9%, those of phosphorous ether are 99.0% and 93.2% and those of trimethylbenzene are 99.0% and 98.5%,which meet the recycling standards of the enterprises.In this paper, the works provides a new solution for the recycling of waste solvents produced by the production process of glufosinate-ammonium.