Study On The Synthesis Of Neopentyl Glycol Dimethylacrylate By Transesterification

In this paper, the process for preparing NPGDA by transesterification over three kinds catalysts (solid acid, alkali metals, organic tin compounds) were employed. The effects of reaction conditions on reaction results were studied and the catalytic activities of them were compared. The interesterification rate equation and the pparent kinetics model were established. The researching content was as follows:1. Neopentyl glycol dimethacrylate was prepared by inesterification of methyl methacrylate with neopentyl glycol over sodium bisulfate and toluene-p-sulfonic acid as the catalysts. Inesterification reaction conditions on the yield were investigated and the catalytic activities of the two catalysts were compared. The experimental results indicated that sodium bisulfate exhibited higher catalytic activity. The optimum conditions were obtained as follows: methyl methacrylate-to-neopentyl glycol molar ratio is 4:1; sodium bisulfate 2.5% ; hydroquinone 0.625% ; reaction temperature 100-105℃; reacting for 8.0h, under which the yield of the ester could reach more than 84.0%.2. Neopentyl glycol dimethacrylate was prepared by inesterification of methyl methacrylate with neopentyl glycol over NaOH ,KOH and K2CO3 as the catalysts were studied and the catalytic activities of the three catalysts were compared. The experimental results indicated that KCO₃ exhibited higher catalytic activity. The optimum conditions were obtained as follows: methyl methacrylate-to-neopentyl glycol molar ratio is 4:1; KCO₃ 3.5% ; hydroquinone 0.625% ; reaction temperature 100-105℃;reacting for 9 h, under which the yield of the ester could reach 60.9%.3. Neopentyl glycol dimethacrylate was prepared by inesterification of methyl methacrylate with neopentyl glycol over dibutyltin oxide and dibutyltin dilaurate as the catalysts were studied and the catalytic activities of the two catalysts were compared. The optimum conditions were obtained as follows: methyl methacrylate-to-neopentyl glycol molar ratio is 5:1; dibutyltin oxide 1.5%; hydroquinone 0.625% ; reaction temperature 110-115℃; reacting for8 h, under which the yield of the ester could reach 94.4%.4. The interesterification rate equation and the pparent kinetics model were established under the condition,dibutyltin oxide as the catalysts.The result is the interesterification follows the first order reaction kinetics.