硫酸铈催化合成乙酸异戊酯

采用硫酸铈为催化剂合成乙酸异戊酯，考察了催化剂用量、醇酸物质的量比、反应时间及催化剂重复使用次数等因素对收率的影响。结果表明该催化剂具有催化活性高，易分离回收，可重复使用，废液排放量少等优势。最佳反应条件下，收率为81．2％。     

硫酸氢钾催化合成尼泊金丁酯

采用KHSO4为催化剂合成了尼泊金丁酯,考察了催化剂用量、正丁醇与对羟基苯甲酸摩尔比、反应时间、催化剂重复使用次数及带水剂等因素对收率的影响。结果表明:KHSO4具有催化活性高,易分离回收,重复使用性良好等优势。最佳反应条件为:正丁醇与对羟基苯甲酸摩尔比为3∶1,催化剂用量3g,反应时间3h,收率92.9%。     

硫酸镓改性离子交换树脂催化合成异丁酸异丁酯

首次采用硫酸镓与阳离子交换树脂作用制备的改性离子交换树脂为酯化催化剂催化合成了食用香料异丁酸异丁酯。考察了催化剂用量、醇酸物质的量比、反应时间、带水剂种类及催化剂重复使用性等因素对产品收率的影响。结果表明,该催化剂具有催化活性高,易分离回收,后处理方便,不需加带水剂,重复使用性好等优势,能够克服浓硫酸为均相酯化催化剂存在的严重腐蚀设备、后处理工艺复杂、废液排放量多、环境污染严重等缺点。硫酸镓改性离子交换树脂是合成异丁酸异丁酯的优良催化剂,可基本实现目标产物的环境友好合成。最佳反应条件为:异丁酸0.2mol,醇酸物质的量比1.6,催化剂1.25g,反应时间60min,收率可达93.9%。该催化剂经简单烘干再生处理就有良好的重复使用性,第7次使用收率仍可达83.6%。     

硫酸镓催化合成丁酸异戊酯的研究

以硫酸镓为催化剂,正丁酸和异戊醇为原料合成了丁酸异戊酯。考察了催化剂用量、醇酸物质的量比、反应时间及催化剂重复使用次数等因素对收率的影响。结果表明,硫酸镓是高效、经济且环境友好的酯化催化剂。适宜反应条件下收率可达92．0％。     

硫酸镓催化合成丙酸正丁酯

目的研究硫酸镓在合成丙酸正丁酯工艺中的催化性能。方法考察硫酸镓用量、醇酸物质的量比、反应时间及催化剂重复使用次数等因素对收率的影响。结果硫酸镓催化活性高,易分离回收,操作简单,后处理方便,重复使用性良好。最佳反应条件下收率为86.03%。结论硫酸镓是合成丙酸正丁酯的良好催化剂。     

硫酸镓催化合成尼泊金丁酯

首次采用硫酸镓为催化剂合成了尼泊金丁酯,考察了催化剂用量、醇酸物质的量比、反应时间、催化剂重复使用次数及带水剂等因素对收率的影响.结果表明,该催化剂具有催化活性高,后处理方便,不需加带水剂等优势.最佳反应条件为:醇酸物质的量比为4,催化剂用量0.6g,反应时间5h,收率达94.8%.     

硫酸氢钾催化合成己酸己酯

目的研究硫酸氢钾在合成己酸己酯工艺中的催化性能。方法考察了硫酸氢钾用量、醇酸物质的摩尔比、反应时间、带水剂用量及催化剂重复使用次数等因素对收率的影响。结果硫酸氢钾具有催化活性高,易分离回收,操作简单,后处理方便,重复使用性良好等优势。最佳反应条件下收率为9 9.4%。结论硫酸氢钾是合成己酸己酯的良好催化剂。     

硅胶固载硫酸镓催化合成己酸戊酯

目的研究硅胶固载硫酸镓在合成己酸戊酯工艺中的催化性能。方法考察硅胶固载硫酸镓用量、醇酸物质的量比、反应时间、带水剂用量及催化剂重复使用次数等因素对收率的影响。结果硅胶固载硫酸镓具有催化活性高,易分离回收,操作简单,后处理方便,重复使用性良好等优点。最佳反应条件下收率为9 4.0%。结论硅胶固载硫酸镓是合成己酸戊酯的良好催化剂。     

硫酸铈催化合成乙酸丁酯

目的研究硫酸铈在合成乙酸丁酯工艺中的催化性能。方法考察了硫酸铈用量、醇酸物质的量比、反应时间及催化剂重复使用次数等因素对收率的影响。结果硫酸铈具有催化活性高,易分离回收,重复使用性好,废液排放量少等优点。适宜条件下收率达84.7%。结论硫酸铈是合成乙酸丁酯的良好催化剂。     

硫酸镓催化合成丙酸正丁酯

目的研究硫酸镓在合成丙酸正丁酯工艺中的催化性能。方法考察硫酸镓用量、醇酸物质的量比、反应时间及催化剂重复使用次数等因素对收率的影响。结果硫酸镓催化活性高，易分离回收，操作简单，后处理方便，重复使用性良好。最佳反应条件下收率为86．03％。结论硫酸镓是合成丙酸正丁酯的良好催化剂。     

丁酸异戊酯的催化合成

以自制复合硫酸铁Fe2 (SO4 ) 3 K2 S2 O8为催化剂 ,正丁酸与异戊醇为原料合成了丁酸异戊酯。最佳合成条件下酯收率达 88 5 5 %。该催化剂具有价廉易得 ,催化活性好 ,后处理工艺简单 ,无腐蚀 ,重复使用性较好 ,无环境污染等优点。     

没食子酸异戊酯的微波快速合成

以没食子酸和异戊醇为原料,对甲苯磺酸为催化剂,微波辐射合成了没食子酸异戊酯。单因素实验确定的最佳反应条件为:酸醇摩尔比1∶7.5(没食子酸0.03 mol),催化剂用量3.00 g,反应温度125℃,微波辐射功率400 W,辐射时间17 min,产率达88.72%。     

离子液体催化合成香料乙酸异戊酯

冰醋酸和异戊醇在离子液体[(C2H5)3NH][HSO4]的催化作用下,合成香料乙酸异戊酯.通过正交试验优化反应条件,考察反应时间、反应温度、醇酸摩尔比、离子液体用量4个因素对产率的影响.优化的最佳反应条件为:冰醋酸0.02mol,反应时间4h,反应温度90℃,醇酸摩尔比0.9∶1,离子液体用量2g,产率达到78.1％.离子液体可循环使用4次,催化活性基本不变.     

Improved production of isoamyl acetate by a sake yeast mutant resistant to an isoprenoid analog and its dependence on alcohol acetyltransferase activity, but not on isoamyl alcohol production

1-Farnesylpyridinium (FPy), an analog of isoprenoid farnesol, strongly inhibited the growth of sake yeast at 120 microM in YPD medium, whereas at 30 microM it reduced cellular production of isoamyl acetate to 20% of the control level despite the absence of inhibitory effect on CO2 evolution. The FPy-resistant mutant A1 was characterized by the high production of flavor compounds represented by a nearly threefold increase in the level of isoamyl acetate in YPD medium in which the level of isoamyl alcohol as its precursor remained almost unchanged. The FPy resistance phenotype of strain A1 was not accompanied by cellular resistance to either the L-leucine analog or L-canavanine, which alters yeast amino acid metabolism in favor of isoamyl alcohol production. Alcohol acetyltransferase (AATase) activity was high in strain A1, which further increased in response to isoamyl alcohol accumulation in medium. Flavor compound production in sake brewing could be improved using strain A1, resulting in a 1.4-fold increase in isoamyl acetate production in spite of a limited production of isoamyl alcohol.     

Enhanced production of isoamyl acetate from beet molasses with addition of fusel oil by Williopsis saturnus var. saturnus

Fusel oil which contains high level of amyl alcohols (approximately 45–55%) is a by-product obtained from the distillation of alcohol made by fermentation of molasses. Williopsis saturnus is a yeast which is able to convert isoamyl alcohol into isoamyl acetate. The aim of this study was to increase the formation of isoamyl acetate by the addition of fusel oil at the ratios of 1%, 2% and 3% (v/v) to molasses based fermentation medium using W. saturnus. It was found out that bioconversion of added fusel oil into isoamyl acetate was possible and an addition of 1% fusel oil led to an increase in isoamyl acetate concentration from 118 to 354 mg/L.     

酱香型白酒发酵过程中异戊醇的控制研究

在单因素试验研究基础,对影响酱香型白酒发酵主要杂油醇成分异戊醇的酵母添加量、糖化酶添加量、蛋白酶添加量、曲粮比例进行了优化研究,结果组合A2B1C2D2条件下(即酵母添用量加量2%,糖化酶用量2×103U/g,蛋白酶添加量20 U/g,曲粮比例1:1。),异戊醇的产量为0.36×10-1g/L,相对于未添加酵母降低89.80%,表明此优化条件对降低酱香型白酒发酵异戊醇含量效果明显,几个影响因素中,酵母添加量影响显著。     

Foaming properties of β-Lactoglobulin: impact of pre-heating and addition of isoamyl acetate

Summary Foaming properties of solutions of β-lactoglobulin alone or in a mixture with isoamyl acetate were investigated through a conductimetric method. It was observed that addition of isoamyl acetate to β-lactoglobulin at molar ratios, R = 1 and 2 led to enhanced foaming properties in comparison with β-lactoglobulin alone. In regards to the observed changes in tryptophan fluorescence properties, it is suggested that β-lactoglobulin + isoamyl acetate might form a complex with a specific surface activity.     

澄清型香蕉汁的挥发性物质研究

利用固相微萃取 (SPME)法浓缩香蕉汁香味物质 ,用气相色谱 质谱 (GC MS)检测、鉴定其中的各种挥发性成分。结果表明 ,SPME法可用于香蕉汁香味成分的快速鉴定。与新鲜香蕉相比 ,香蕉汁保留了新鲜香蕉特征性香味成分如乙酸异戊酯、丁酸异戊酯、异戊酸异戊酯、异榄香素等总含量的 71 5 0 %,表明果汁保留了香蕉鲜果主要风味。但果汁中醇类、有机酸与羰基化合物含量增多 ,并出现了二甲硫醚、呋喃等热加工产物。     

Improvement of isoamyl acetate productivity in sake yeast by isolating mutants resistant to econazole

Sake yeast strains were improved so as to produce larger amounts of isoamyl acetate than the parental strain by isolating econazole-resistant mutants. Econazole, an imidazole antimycotic, directly interacts with unsaturated fatty acids in the yeast cell membrane, where it also inhibits the synthesis of ergosterol and decreases the ratio of unsaturated to saturated fatty acids. In contrast, alcohol acetyltransferase (AATase), which catalyzes the synthesis of isoamyl acetate, is inhibited by unsaturated fatty acids. Fifty econazole-resistant mutants were isolated from a sake yeast, Kyokai no. 701, several of which produced approximately 1.4 to 2.4 times more isoamyl acetate and an almost equal amount of isoamyl alcohol compared with the parental strain. The AATase activities of the mutants in koji extract were 1.2 to 1.4 times higher, and the unsaturated to saturated fatty acid ratios were lower, than in the parental strain.