摘要
以1,3-二甲基黄嘌呤钠盐(茶碱钠盐)为原料,以碳酸二甲酯(DMC)作为甲基化试剂合成咖啡因。使用~1HNMR、^(13)CNMR和LC-MS等对咖啡因的结构进行了表征。考察了催化剂种类和用量、物料比[n(茶碱钠盐)∶n(DMC)]、反应温度、反应时间、母液循环次数对咖啡因收率的影响。结果表明,最佳的合成工艺条件为:以水为主的乳化液[m(水)∶m(乙二醇)∶m(OP-10)=14∶1∶1]为溶剂,茶碱钠盐的浓度为1.25 mol/L,催化剂Na Y用量为茶碱钠盐质量的5%,土耳其红油为乳化剂,其用量为茶碱钠盐质量的5%,n(茶碱钠盐)∶n(DMC)=1.00∶1.30,反应温度130℃,反应时间3 h。在此条件下,咖啡因的收率为97.8%。母液循环使用7次后,咖啡因的收率仍可达96.0%。
A new green process for synthesis of caffeine was developed by using 1,3-dimethylxanthine sodium salt（theophylline sodium salt） as raw material,dimethyl carbonate（DMC） as methylating reagent.The product was characterized by means of ~1HNMR,^（13）CNMR and LC-MS.The effects of kinds and dosage of catalyst,mole ratio of reactants,reaction temperature,reaction time and times of mother liquor cycles on the yield of caffeine were investigated.The optimum reaction conditions were obtained as follows： the emulsion [m（water） ∶ m（ethylene glycol） ∶ m（OP-10） = 14∶1∶1]was used as solvent,the dosage of Na Y as catalyst was 5% of the mass of theophylline sodium salt,the dosage of Turkey red oil as emulsifier was 5% of the mass of theophylline sodium salt,the mole ratio of theophylline sodium salt to DMC was 1.00 ∶ 1.30,the reaction temperature was 130 ℃,and the reaction time was 3 h.Under these conditions,the yield of caffeine was 97.8%.The yield of caffeine could still reach 96.0% even after the mother liquor was recycled for seven times.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2017年第11期1316-1320,共5页
Fine Chemicals
基金
2017年度山东省重点研发计划(公益类专项)项目(2017GSF17106)~~
关键词
碳酸二甲酯
甲基化
咖啡因
精细化工中间体
dimethyl carbonate
methylation
caffeine
fine chemical intermediates
