The present invention discloses a method for preparing alpha-acetyl-gamma-butyrolactone. The steps are as follows: adding ethyl acetate and sodium carbonate to a three-port bottle, dropping gamma-butyrolactone at 44_46_C, stirring, mixing ethyl acetate with liquid acetaldehyde, dropping into the reaction solution, stirring and reacting at 54_58_C for 1.5_2.5 h after mixing. The reaction solution was added to the autoclave at 80 85 C for 5 6 h, and then to room temperature. The reaction solution was added to four flasks. The pH was adjusted to 6 7 by adding sulphuric acid at 3 5 C. Solids were precipitated in the process of dropping. After dropping, the pH was stirred for 11 13 h, and the solid was removed by filtration. The filter cake was washed with ethyl acetate and vacuum rotary evaporation was carried out. After removing ethyl acetate, crude products can be obtained without distillation, and crude products can be obtained by vacuum distillation. The preparation method is easy to obtain, cheap, easy to operate, and has high yield, and is suitable for industrial production.
【技术实现步骤摘要】
一种制备α-乙酰-γ-丁内酯的方法
本专利技术涉及一种制备α-乙酰-γ-丁内酯的方法。
技术介绍
α-乙酰-γ-丁内酯(英文名α-acetyl-γ-butyrolactone)是一种无色透明的液体,带有酯类气味,CAS号517-23-7。α-乙酰-γ-丁内酯可以通过显色反应用于伯胺或磺胺类药物的分析,同时其也是一种用途广泛的化工中间体,常用于合成维生素B1,抗精神病药物利培酮、抗惊厥及镇静催眠药物盐酸氯美噻嗪、叶绿素、延心痛、氯喹、3-巯基-4-氧代-戊基乙酸酯、环丙胺、杀菌剂丙硫菌唑等药物。目前α-乙酰-γ-丁内酯主要有两种合成工艺路线:以γ-丁内酯,乙酸乙酯为原料,强碱为缩合剂,通过Claisen缩合制得;另一种以醇为溶媒,强碱为缩合剂,由乙酰乙酸乙酯(或乙酰乙酸甲酯、乙酰乙酸叔丁酯)与环氧乙烷缩合闭环制得。由于环氧乙烷为危险程度较高的危险化学品,所以国内生产企业均采用第一种以γ-丁内酯,乙酸乙酯为原料的工艺路线:利用强碱为缩合剂使γ-丁内酯去质子化,与乙酸乙酯发生缩合反应,生成α-乙酰-γ-丁内酯,根据缩合剂和操作的不同该路线可分为四种方法:金属钾为缩合剂制取、醇钠作为缩合剂制取、金属钠为缩合剂制取、氟化物为缩合剂气相制取。这条路线具有高收率低成本的优点,但仍存在操作繁琐和重大环境污染问题。
技术实现思路
本专利技术的目的在于提供一种制备α-乙酰-γ-丁内酯的方法。本专利技术通过下面技术方案实现:一种制备α-乙酰-γ-丁内酯的方法,包括如下步骤:向三口瓶中加入75-85份乙酸乙酯和40-50份碳酸钠,在44-46℃条件下滴加35-45份γ-丁内酯,搅拌4 ...
【技术保护点】
1.一种制备α‑乙酰‑γ‑丁内酯的方法,其特征在于包括如下步骤:向三口瓶中加入75‑85份乙酸乙酯和40‑50份碳酸钠,在44‑46℃条件下滴加35‑45份γ‑丁内酯,搅拌40‑50min,将50‑60份乙酸乙酯与30‑40份液体乙醛均匀混合,在1.5‑2.5h内滴加入反应液,混合均匀后于54‑58℃搅拌反应1.5‑2.5h,将反应液加入高压釜中80‑85℃保温反应5‑6h,反应结束后通水降温至室温,将反应液加入四口瓶中,用20‑30份乙酸乙酯清洗高压釜,并将洗液并入反应液中,在3‑5℃下缓慢滴加质量分数为65%硫酸调节pH至6‑7,滴加过程中有固体析出,滴加结束后,在25‑35℃下搅拌11‑13h,复测pH不变,过滤除去固体,用乙酸乙酯洗滤饼,45‑55℃减压旋蒸,除去乙酸乙酯,至不出馏后得粗品,粗品直接经减压精馏即得;各原料均为重量份。
【技术特征摘要】
1.一种制备α-乙酰-γ-丁内酯的方法,其特征在于包括如下步骤:向三口瓶中加入75-85份乙酸乙酯和40-50份碳酸钠,在44-46℃条件下滴加35-45份γ-丁内酯,搅拌40-50min,将50-60份乙酸乙酯与30-40份液体乙醛均匀混合,在1.5-2.5h内滴加入反应液,混合均匀后于54-58℃搅拌反应1.5-2.5h,将反应液加入高压釜中80-85℃保温反应5-6h,反应结束后通水降温至室温,将反应液加入四口瓶中,用20-30份乙酸乙酯清洗高压釜,并将洗液并入反应液中,在3-5℃下缓慢滴加质量分数为65%硫酸调节pH至6-7,滴加过程中有固体析出,滴加结束后,在25-35℃下搅拌11-13h,复测pH不变,过滤除去固体,用乙酸乙酯洗滤饼,45-55...
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