【摘要】 改进硝酸氧化乙醛制乙二醛反应的加料方式,考察了反应温度、硝酸浓度和引发剂用量等因素对乙二醛选择性和收率的影响。结果表明,采用在引发阶段先快速加入适量硝酸的加料方式,能够有效控制反应温度,使反应过程中生成的NO不逸出而较好地保护醛基,可明显提高乙二醛的选择性和收率。在反应温度为40℃、硝酸浓度为35%(质量分数)、乙醛与硝酸物质的量之比为0.75、亚硝酸钠用量为乙醛质量的0.9%、引发时硝酸的加入量为硝酸总量的10%和反应3.5 h的条件下,选择性可达80%左右,乙二醛收率高于47%(按物质的量计算)。更多还原

【Abstract】 The feed way was improved for preparing glyoxal from acetaldehyde and nitric acid and the effects of reaction temperature,nitric acid concentration and initiator dosage on selectivity and yield of glyoxal were investigated.The results showed that adding a quantity of nitric acid rapidly at the beginning of initiation could control reaction temperature effectively and prevent nitric oxide from escaping which protected aldehyde group,so that the selectivity and yield of glyoxal increased obviously.Under the optimal conditions of reaction temperature 40℃,nitric acid mass fraction 35%, molar ratio of acetaldehyde to nitric acid 0.75,mass fraction of sodium nitrite to acetaldehyde 0.9% and nitric acid at the beginning to total nitric acid 10%,selectivity and yield of glyoxal were 80%and 47%,respectively,after reaction for 3.5 h,更多还原