摘要
研究了以硫酸和氯化铝为酸性介质,亚硝酸钠为催化剂,常压氧气氧化乙二醛制备乙醛酸,进而在不添加酸性催化剂的条件下直接合成尿囊素的技术路线。通过对各影响因素的考察确定了氧化反应适宜的工艺条件为:乙二醛质量分数25%,钠醛比0.2、酸醛比0.4、反应温度25℃、反应时间3h,在此条件下,乙醛酸收率为76.12%;缩合反应适宜的工艺条件为:乙醛酸尿素投料比1∶4,反应温度75℃,反应时间3h,此时尿囊素的收率可达60.75%。
The technical route of allantoin synthesis was studied, which was characterized with the glyoxylic acid preparation by oxygen oxidation of glyoxal at ambient pressure with sulfuric acid and a- luminum chloride as acid medium, and sodium nitrite as catalyst first, then direct synthesis of allanto- in without the addition of acid catalyst. The suitable process conditions for the oxidation were deter- mined after investigation of affecting factors, that is, mass concentration of glyoxal was 25%, the molar ratio of sodium nitrite to glyoxal was 0.2, molar ratio of sulfuric acid to glyoxal was 0.4, reac- tion temperature was 25 ℃ and reaction time was 3 h. Under these conditions, the yield of glyoxylic acid was up to 76.12%. The suitable conditions for condensation reaction were as follows： the molar ratio of glyoxylic acid to urea was 1 ： 4, reaction temperature was 75 ℃and reaction time was 3 h. Under these conditions, the yield of allantoin was up to 60.75%.
出处
《精细石油化工》
CAS
CSCD
北大核心
2013年第1期67-70,共4页
Speciality Petrochemicals
关键词
乙二醛
氧气
乙醛酸
尿囊素
glyoxal
oxygen
glyoxylic acid
allantoin
