酮缩醇

Organic substances (diethylene glycol, glycol methyl ether and methyl ethyl ketone) were used as nonsolvent additives and N-methyl-2-pyrrolidone used as a solvent in membrane preparation. The effects of PPESK concentration, the type of additives and the NSA concentration in casting solution on the morphology and performance of the PPESK hollow fiber ultrafiltration membrane were systematically investigated.

以PPESK为膜材料，NMP为溶剂，水为凝胶剂，选用乙二醇甲醚、一缩二乙二醇和丁酮为非溶剂添加剂，系统研究了聚合物浓度、添加剂种类和含量对PPESK中空纤维超滤膜结构和性能的影响，制备了一系列具有不同孔径和通量的中空纤维超滤膜。

In ethylene glycol solution, 1 was converted into 1-oxo-13c-(2-hydroxyethoxy)-1, 13c-dihydro-dibenzo -xanthene (23) and ketal compound 7a, 13bethylenedioxy-1-hydroxy-7a, 13b-dihydro-dibenzo -xanthene (24), the structure of which was confirmed by X-ray single crystal diffraction.

在乙二醇中反应时，1被氧化为二苯并咕吨型的23和缩酮型的7a，13b-亚乙二氧-1-羟基-7a，13b-二氢-二苯并-咕吨（24）。24的结构得到X-ray单晶衍射的证实。

Quinone methides, generated in situ from the reaction of 4-hydroxycoumarin with benzaldehyde, formaldehyde and pentanal, underwent the Diels-Alder reaction with silyl enol ethers to give a series of 3,4-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran derivatives in high yields.

通过4-羟基香豆素与苯甲醛、甲醛和戊醛缩合产生的quinone methide与烯醇硅醚的Diels-Alder反应，以较高产率合成了一系列含有硅氧基的3，4-二氢-2H，5H-吡喃并[3，2-c][1]苯并吡喃-5-酮衍生物。

Fe2(SO4)3/SiO2 catalyst is excellent in stability and reusability, and yield of cyclohexanone 1, 2-propanediol ketal keeps at 88.90% after being used for 5 times.

Fe2(SO4)3/SiO2催化剂具有良好的德定性，重复使用5次后环己酮1， 2-丙二醇缩酮的收率为88.90%。

The optimal conditions were found to be: n:n=1:1.5; mass fraction of catalyst to reactants, 1.0%; reaction time, 0.75 h and dried cyclohexane, 8 mL. Under these conditions, the yield of cyclohexanone ethylene ketal was 87.7%.

实验结果表明，在n∶n=1.0∶1.5、催化剂用量占反应物料总质量的1.0%、反应时间0.75 h的条件下，环己酮乙二醇缩酮的收率为87.7%。

Cyclohexanone ethylene ketal was synthesized using vitamin C as the catalyst by microwave irradiation solvent-free method.

以维生素C为催化剂，采用微波辐射无溶剂催化合成环己酮乙二醇缩酮，探索了不同反应条件对产率的影响。

Hβ zeolite ; seven-member-ring ketal ; 1; 4-butanediol ; synthesis ; catalyst

Hβ；七元环缩酮； 1； 4-丁二醇；环己酮；合成；催化剂

Catalytic Synthesis of Cyclohexanone 1, 2-Propylene Ketal by Chitosan Supported with Iodine

篇名 壳聚糖负载单质碘催化合成环己酮1， 2-丙二醇缩酮

Efficient conversion of pentaerythrite with carbonyl compounds,aldehyde or ketone,to the corresponding pentaerythritol dialdehyde or diketone compounds in the presence of ammonium hydrogen sulfate under microwave irradiation without solvent was described.

无溶剂微波照射下，通过硫酸氢铵催化季戊四醇和醛、酮反应合成了季戊四醇双缩醛、酮化合物。通过IR和1HNMR对产物结构进行了表征，研究了反应条件对产率的影响，最佳反应条件为微波照射功率750 W，照射时间1.5 min

The beta-thioalkoxyalcohols could be obtained in good yields by the reaction of dialkyl-substituted propargylic dithioacetals with a series of carbonyl compounds.

我们发现在铁触媒和格林那试剂的存在下，利用双烷基取代炔丙基硫缩酮和羰基化合物反应生成的beta-硫烷氧基醇，可以进行不常见的beta-氧消去反应，而得到烯炔衍生物。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。