The Synthesis And Process Optimization Of New Curing Agent Based On Dimethyl Adipate

Dimethyl adipate is a very important fine chemical product and chemical raw material with low toxicity, good thermal stability, low volatility and high biodegradability. It can be not only applied to the manufacture of plasticizers, lubricants, adhesives, paints and coating paints, but also to the synthesis of pharmaceutical intermediates and spices. With dimethyl adipate as raw material, several kinds of powder coating curing agents with outstanding performance and applied in many field were synthetized, and the processes also optimized.Firstly, some P-hydroxyalkyl amides were synthetized from dimethyl adipate. We explored a variety of new catalysts to prepare the N,N,N’,N’-tetra(β-hydroxyethyl)adipate amide which has outstanding performance in the powder coating as curing agent. With the load solid base as catalyst which has a good catalytic performance, the process optimization was carried out. When the load solid alkali accounted for1.04%of the total material (the content of alkali was only0.52%), the yield was up to93.55%and the melting point was121-123℃.Secondly, adipic dihydrazide which is a latent curing agent were synthesized from dimethyl adipate. The factors influencing the reaction results such as the material ratio, amount of solvent, reaction temperature and reaction time have been studied. The optimized process as follows:the ratio of dimethyl adipate with hydrazine hydrate is1:2.5, the mass of anhydrous ethanol as0.68times as dimethyl adipate, the reaction temperature is45℃, the reaction time is4.5h, the yield was93.55%, which have been examined by pilot scale reaction. The content of the production was98.60%by the UV spectrophotometer determined.Finally, a novel oxadiazoline was synthesized by cyclization of acetic anhydride with hydrazone, the latter was prepared from adipic dihydrazide (ADH) with benzaldehyde. The process of cyclization was optimized:the ratio of adipic acid benzaldehyde hydrazone to acetic anhydride in mole was1:132, and triethylamine as the acid binding agent added in a mole of12times as the adipic acid benzaldehyde hydrazone under the atmosphere of nitrogen, temperature of cyclization was92℃, cyclization time was6h, the yield was70.44%, and a mild synthesis method was obtained.