减压蒸馏

Using citral and acetone as starting materials, the aldolcondensation was carried out, and then the final product wasobtained by distillation under vacuum.

以柠檬醛和丙酮为起始原料进行醇醛缩合反应，经减压蒸馏得到最终产物。

The failure tree for atmospheric tower is established with deductive method based on the theory of failure tree analysis.

根据故障树分析理论，用演绎法建立了常减压蒸馏装置常压塔的失效故障树。

The excessive β-ionone and the catalysts can be reused via vacuum distillation and filtration.

未反应的原料经减压蒸馏回收利用，催化剂经过滤分离、活化，其重复使用性良好。

Results show that 4-oxo-β-ionone is the major product with yield of 53.5% under the conditions as follows: reaction temperature 45℃, reaction time 24 h, the molar ratio of n: n(NaClO3): n 20: 100: 3, and pH value of solution in 1-3; on the other hand, 5,6-epoxy-β-ionone is major product with yield of 25.4% when reaction temperature is 40℃, reaction time is 24 h, the molar ratio of n: n(NaClO3): n is 20: 120: 5, and pH values of solution is 3. The excessive β-ionone can be recovered by vacuum distillation for reusing again. 4-oxo-β-ionone and 5,6-epoxy-3-ionone were purified by recrystallization and silica gel column chromatograph respectively with the purity over 98%.

研究结果表明：氯酸钠氧化β-紫罗兰酮的反应主要生成4-氧代－β-紫罗兰酮和5，6-环氧－β-紫罗兰酮，经重结晶和硅胶柱层析分离，纯度高于98%；4-氧代－β-紫罗兰酮的有利合成条件是反应温度为45℃，反应时间为24h，溶液的pH值为1~3，反应物配比n：n(NaClO3)：n为20：100：3，最佳收率为53.5%；5，6-环氧－β-紫罗兰酮有利的合成条件是反应温度为40℃，反应时间为24h，溶液的pH值为3，反应物配比n：n(NaClO3)：n为20：120：5，其收率为25.4%；未反应的β-紫罗兰酮经减压蒸馏回收后可重复使用。

This apparatus was designed based on summarizing the most synthetic processes of lactide presently.

本文在总结了目前众多聚乳酸单体——丙交酯的合成技术的基础上，选用减压蒸馏工艺并加以改进，设计出最佳的实验装置，使丙交酯的产率从30％提高到45％，并对重结晶后的母液进行有效的回收，回收率也能达到40％，对回收后的丙交酯进行了测试分析，证明了回收过程的可行性。

The vacuum distillation technology for production of technical methylnaphthalene was introduced.

本文介绍了采用减压蒸馏法生产工业甲基萘的两种工艺路线，可生产不同品级的产品，并详细介绍了有关操作参数和工艺要点，进行了经济效益的讨论。

The condensation reaction,in which the yield of intermediate product after refining process was more than 90%,used iso-butylaldehyde and formaldehyde as materials,Et 3N as catalyst.The hydrogenation,in which the conversion of hydroxypivaldehyde and selectivity of NPG were respectively 99% and 95%,used Cu-ZnO as catalyst,and ethanol as solute,meanwhile in the hydrogenation,the impurity in material could also ...

缩合反应采用异丁醛和甲醛为原料，三乙胺为催化剂，在 60℃左右反应，缩合产物经减压蒸馏和结晶、干燥，得到收率为 90 %以上的中间体羟基戊醛；加氢反应采用自制的Cu -ZnO催化剂，乙醇为溶剂，在 15 0℃将HPA加氢生成新戊二醇，HPA转化率为 99%，新戊二醇收率在 95 %以上，而且HPA缩合反应的副产物在加氢反应中也转化为新戊二醇。

Microwave vacuum distillation and ethanol as solvent are used to extract pepper oil and piperine from black pepper in this research.

采用微波减压蒸馏及乙醇提取法对胡椒油和胡椒碱的提取进行了研究。

This method is successfully applied to a problem over a horizon of one week involving 2 vessels, 6 portside tanks, 6 refinery tanks, 2 CDUs, and 6 crude oil types.

采用该方法成功求解了一个时间为1周、2艘油轮、6个码头罐、6个厂区罐、2套常减压蒸馏装置、6种原油的调度问题，表明此方法是切实可行的。

Said preparation method includes: dissolving curcumin and polyvinyl pyrrolidone according to mass ratio of 1:4-1:15 in organic solvent (for example absolute ethyl alcohol, propyl alcohol, isopropyl alcohol and ethyl acetate), making reduced pressure distillation at 55-95deg.C to remove most of ethyl alcohol to obtain paste material, quickly pouring the paste material into a stainless steel disk, vacuum drying at 60-90deg.C in drying oven and pulverizing.

本发明将姜黄素和聚乙烯吡咯烷酮按质量比1∶4～1∶15溶于有机溶剂(如无水乙醇、丙醇、异丙醇、乙酸乙酯等)，于减压蒸馏55-95℃下除去大部分乙醇至成糊状，迅速倒入不锈钢盘中，在60-90℃下真空烘箱烘干，用粉碎机粉碎，得到姜黄素固体分散体。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。