一种氰乙酸乙酯合成的新方法

以氰乙酸、无水乙醇为原料,采用酸性树脂催化合成氰乙酸乙酯。分析和讨论了反应温度,氰乙酸与无水乙醇的摩尔比,精馏前粗品质量和精馏操作条件对氰乙酸乙酯的纯度和收率的影响,在该条件下,氰乙酸乙酯的产品纯度可以达到99.5%以上,收率在93.0%以上。     

除草剂吡嘧磺隆的研制

以氰乙酸乙酯、原甲酸三乙酯和甲肼等为主要原料,通过取代、胺化、环化、重氮化和氯磺化等反应制得了除草剂吡嘧磺隆原料药。所得产物的纯度为98·6%,总收率达到39·5%(以氰乙酸乙酯计)。该工艺过程控制和三废处理都比较容易。     

氰乙酸乙氧基乙酯的酯交换合成

氰乙酸乙氧基乙酯是低白化、低气味α-氰基丙烯酸乙氧基乙酯瞬干胶的关键性原料。本文以氰乙酸乙酯、乙二醇单乙醚为原料进行酯交换合成氰乙酸乙氧基乙酯。对反应的物质的量比、催化剂及用量、反应时间等条件进行了考查,最佳工艺条件为:n/n为1/2;催化剂二丁基二月桂氰乙酸乙酯乙二醇单乙醚酸锡用量为氰乙酸乙酯的2.5%;反应时间10 h。在此条件下,反应产率85%,纯度97.3%。     

α-氰基丙烯酸乙酯的无催化合成研究

以氰乙酸乙酯和多聚甲醛为原料合成α 氰基丙烯酸乙酯 ,无催化合成的最优反应条件是 :n(CNCH2 COOC2 H5)∶n[(HCHO) n]=1 0 0∶1 0 5、反应温度 82～ 85℃、溶剂 (乙酸乙酯 )用量 2 0 0mL mol氰乙酸乙酯、反应时间 3h ,合成收率 58.2 % (质量分数≥ 99 0 % )。     

树脂催化水解制备固体氰乙酸的工艺研究

介绍了一种合成固体氰乙酸的新工艺。该工艺以氰乙酸乙酯为原料,经732型阳离子交换树脂催化,通过水解制备固体氰乙酸。考察了反应温度,反应时间,氰乙酸乙酯和水的质量比和氰乙酸乙酯和树脂的质量比对反应的影响。结果表明,最佳的反应条件为:反应温度为90℃,反应时间为10h,水酯质量比为1∶1,酯与树脂质量比为10∶4.5,在该条件下,氰乙酸的最高收率可达88.9%。     

酯化反应合成甲氧基氰乙酸乙酯

用氰乙酸、乙二醇单甲醚为原料,阳离子交换树脂A-15作为催化剂,以甲苯为带水剂,进行酯化反应制备甲氧基氰乙酸乙酯。通过试验得到最佳的工艺条件为：乙二醇单甲醚与氰乙酸的物质的量比3,催化剂A-15用量4%（质量分数,以氰乙酸为基准,下同）,反应温度130℃,反应时间6h,制备甲氧基氰乙酸乙酯,收率达93%,纯度达95%。产物经IR、1HNMR和GC-MS进行了确定。     

乙氧亚甲基氰乙酸乙酯的合成

氰乙酸乙酯和原甲酸三乙酯在催化剂存在下合成了乙氧亚甲基氰乙酸乙酯，收率达到９０％以上。     

3-脲基-2-氰基-2-丙烯酸乙酯的合成研究

在二甲苯中以氰乙酸乙酯、原甲酸三乙酯和尿素合成3-脲基-2-氰基-2-丙烯酸乙酯.产物用乙酸乙酯重结晶,通过1H NMR对产物结构进行了表征.并对合成工艺进行了优化,得到较适宜的工艺条件:n(氰乙酸乙酯):n(原甲酸三乙酯):n(尿素)=1.0:1.12:1.1,反应时间10 h,收率73.65 %.     

别嘌呤醇合成方法的改进

以氰乙酸乙酯和原甲酸三乙酯为起始原料,合成了标题化合物。经改进的方法与文献相比,产物处理简单,反应产率高,总收率达53.7%,含量≥99.5%。     

低固废氰乙酸乙酯合成工艺研究

采用先酯化后氰化的方法将氯乙酸先酯化为氯乙酸乙酯,然后在相转移催化剂作用下,氯乙酸乙酯发生氰化反应制得氰乙酸乙酯。优化后的最佳反应条件为:酯化回流时间为3.5h,氯乙酸与乙醇物质的量比为1∶2.0;氰化反应时间为6.0h,反应温度为60℃,催化剂为聚乙二醇与四丁基溴化铵的复配物(m(聚乙二醇)∶m(四丁基溴化铵)=1∶0.4)。在此条件下,氰乙酸乙酯的总收率达到89.58%(以氰乙酸计)。该方法反应步骤少,氰乙酸乙酯含量高,解决了先氰化后酯化固废量大,成本较高的问题。     

Evaluation of Waters Silica Sep‐Pak cartridges for short chain fatty acid ethyl ester recovery

Waters Silica Sep‐Pak cartridges were evaluated for their performance in trapping short chain fatty acid ethyl esters. Liquid solutions of ethyl butyrate, ethyl valerate and ethyl caproate were injected onto cartridges. All the esters bound to the matrix and were eluted with four bed volumes of ethanol for ethyl butyrate and two bed volumes of ethanol for ethyl valerate and ethyl caproate. Samples of esters stripped with an air stream for 1 min and trapped on cartridges were found to vary by less than 8% for ethyl propionate, ethyl butyrate, ethyl valerate and ethyl caproate. Production of ethyl butyrate by Pseudomonas fragi CRDA 037 resting cells during biotransformation was efficiently evaluated using these cartridges. Variations between samples were found to be less than 10%. © 2000 Society of Chemical Industry     

菊酸乙酯的合成工艺

研究了菊酸乙酯合成的工艺条件，采用了自制的催化剂，在优化条件下，菊酸乙酯的收率超过８０％。     

含氮杂环羧酸乙酯的微波合成

以异烟酸(烟酸)和无水乙醇为原料,浓硫酸为催化剂,在微波辐射下合成异烟酸(烟酸)乙酯,其结构通过红外光谱、质谱进行了确证。同时研究了醇酸物质的量比、催化剂用量及反应时间对酯化产率的影响,结果表明,醇酸物质的量比为8∶1,催化剂用量为8.0mL(0.15mol),反应时间为40min时,微波辐射功率为300 W的优化条件下,酯化产率最高,相应的产率为89.2%和95.0%。     

三氟乙酰乙酸乙酯的合成

乙酸乙酯与三氟乙酸乙酯（摩尔比为3：1）在乙醇钠作用下进行克莱森酯缩合反应,得到三氟乙酰乙酸乙酯。反应在50℃下进行5h,以过量的乙酸乙酯与生成的乙醇共沸除掉乙醇,使反应进行完全。除掉溶剂后．减压蒸馏得产品,收率75．9％。     

二氟乙酰乙酸乙酯的合成

二氟乙酸乙酯和乙酸乙酯(摩尔比为1∶3)在乙醇钠催化下进行克莱森酯缩合反应,得到二氟乙酰乙酸乙酯。反应在50℃下进行4h,以过量的乙酸乙酯和反应生成的乙醇共沸除掉乙醇,使反应进行完全。除掉溶剂后减压蒸馏得纯度大于99%的产品,产品收率68.14%。     

NO2氧化合成丙酮酸乙酯

研究了以NO2为氧化剂,催化氧化乳酸乙酯合成丙酮酸乙酯的新方法,讨论了氧化剂用量、反应时间、反应温度、催化剂用量等因素对反应的影响。在最佳实验条件下,产品收率大于75%,纯度达98%。本法最大的优点是为NO2废气的回收利用提供了新的途径。     

藏红花酸乙酯的合成研究

以乙酰乙酸乙酯为起始原料，先与异丙叉丙酮发生Michael加成，后经还原、脱水便获得藏红花酸乙酯。三步反应总收率为51．7％。产品经色质分析证明了结构。该合成方法原料价廉易得，反应收率高，适合工业生产。     

邻羟基苯乙醚的间歇精馏分离

通过碱洗将缩合反应产生的邻羟基苯乙醚与邻苯二乙醚分开,再通过间歇精馏确定邻羟基苯乙醚的分离工艺参数。精馏柱内径为38 mm的玻璃柱,内装边长为1.5 mm的小三角填料,填料高度为400 mm,理论板数为13块,回流比为1~2,真空为0.098 MPa,邻羟基苯乙醚精馏收率≥93%,产品纯度≥99%。     

Alcohol Consumption during Pregnancy: Analysis of Two Direct Metabolites of Ethanol in Meconium

Alcohol consumption in young women is a widespread habit that may continue during pregnancy and induce alterations in the fetus. We aimed to characterize prevalence of alcohol consumption in parturient women and to assess fetal ethanol exposure in their newborns by analyzing two direct metabolites of ethanol in meconium. This is a cross-sectional study performed in September 2011 and March 2012 in a series of women admitted to an obstetric unit following childbirth. During admission, socio-demographic and substance use (alcohol, tobacco, cannabis, cocaine, and opiates) during pregnancy were assessed using a structured questionnaire and clinical charts. We also recorded the characteristics of pregnancy, childbirth, and neonates. The meconium analysis was performed by liquid chromatography—tandem mass spectrometry (LC-MS/MS) to detect the presence of ethyl glucuronide (EtG) and ethyl sulfate (EtS). Fifty-one parturient and 52 neonates were included and 48 meconium samples were suitable for EtG and EtS detection. The median age of women was 30 years (interquartile range (IQR): 26–34 years); EtG was present in all meconium samples and median concentration of EtG was 67.9 ng/g (IQR: 36.0–110.6 ng/g). With respect to EtS, it was undetectable (<0.01 ng/g) in the majority of samples (79.1%). Only three (6%) women reported alcohol consumption during pregnancy in face-to-face interviews. However, prevalence of fetal exposure to alcohol through the detection of EtG and EtS was 4.2% and 16.7%, respectively. Prevention of alcohol consumption during pregnancy and the detection of substance use with markers of fetal exposure are essential components of maternal and child health.