Study on the Synthesis of Diethylene Glycol Dibenzoate
|School||Harbin Engineering University|
|Keywords||diethylene glycol benzoic acid butyl titanate plasticizer diethylene glycol dibenzoate|
The plasticizer is the biggest auxiliary of consumption such plastic processing as PVC, etc. It has extensive application in many fields such as in the synthetic rubber, coating, adhesive and chemical industry. The market of plasticizer has been quite ripe.With the rapid development of the plastics industry, the demand for the plastic plasticizer increases year by year. Dimethyl phthalate have occupied more than 80% of the market share of the plasticizer. After DOP was suspected that there was carcinogenic function by the cancer research institute of U. S. A. (NCI), its scope of application was limited. People are looking for and studying the secure substitute which is better than DOP .Diethylene glycol dibenzoate (abbreviate as DEDB) has excellent compatibility, excellent freeze resistance, excellent static resistance, excellent resistance to crocking, excellent thermal stability, low volatility and excellent photostabilization, especially toxicity is much low, LD50 is only 5. 44g/kg. DEDB can be used as the main plasticizer, softening agent, solvent and filling agent, it uses extensively in PVC, polystyrene, polymethyl methacrylate, etc. DEDB also plays a great role in all kinds of thermal adhesive. Administrative departments such as foreign food department, cosmetics department and medicine department think that it can be used as the plasticizer with bigger security exposed to the food wrappings or other additive.According to the domestic and foreign datum, the synthetic method of DEDB by using diethylene glycol, benzoic acid and catalyst butyl titanate was introduced. The affection factors on the reaction such as molar ratio of diethylene glycol and benzoic acid, reaction temperature (control by the amount of toluene ), reaction time and proper amount of catalyst butyl titanate were determined by experiment.The experimental results showed that catalyst had high catalytic activity and stability. The most suitable conditions were as follows: molar ratio of diethyleneglycol and benzoic acid was 1 to 2. 1; mass ratio of butyl titanate and benzoic acid was 1 to 96; mass ratio of toluene and benzoic acid was 0. 18 to 1; reaction time 6h; reaction temperature between 180 and 200 °C, the yield to diethylene glycol dibenzoate was up to 98. 4%.The performance indexes of DEDB were as follows by test: acid value was 2. 5208, esterification degree was 98.40%, viscosity value was 0. 12Pa#s, refractive index was 1. 5407, chromaticity value was between 120 and 130.The choice of sodium hypophosphite and technics of final treatment in this experiment is the innovative work. And some valuable results were gained by experiment. Though the process parameter in this article needs further adjust and perfect, some valuable ways in the preparation of DEDB were brought forward.And these ways will have guidable significance to industrialization application.