关键词: 环状硼酸酯 , 水解稳定性 , 干平衡回流沸点 , 制动液

Abstract: The cyclic borates were synthesized with the equipment attached to the vac pup, the relations between the structures and the boiling points of the borates were investigated, and the effect of the pH value and the structures on the hydrolytic stability was inspected as well. In the same time, the structures of the products were characterized by the IR， and the performance of the products was tested according to the related GB. The results show that the relations between the structures and the boiling point of the 5-membered ring borates with the side chain of tetraethylene glycol alkyl ether of a given polymerization degree as follows: the bigger of the number ratio of carbon to the oxygen, the lower of the boiling point; the large ring borates as follows: the bigger of the number ratio of carbon to the oxygen, the higher of the boiling point. Finally, the products were prepared of which the dry equilibrium reflux boiling point is above 240 ℃, and the conclusion was acquired that the hydrolytic stability of cyclic borates reaches above 96 h when the pH value of the products is around 7 or above. 

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