查询词典 ketene

Reactions of ketene (CH2CO) with some small molecular free radicals play an important role in combustion and atmospheric chemistry. The experimental and theoretical studies to these reactions have attracted many interests of chemists these years.

乙烯酮(CH2CO)与某些小分子自由基的反应在燃烧和大气化学中起着重要作用，近年来已成为化学家们广泛关注的研究课题之一。

Besides, The reaction of aldehydes with dithioacetate enethiolates followed by alkylation effectively gives α-hydroxyl ketene dithioacetals.

此外，用醛与硫代羧酸硫酯反应再通过烷基化也可以有效地获得α-羟基二硫缩烯酮类化合物。

Second, we investigated the aldol reactions of the specialα-oxo ketene dithioacetals with aromatic aldehydes under the mild conditions in good yields.

在温和的条件(室温、30℃)下，高产率地实现了α-羰基二硫缩烯酮与芳香醛的缩合反应。3。

The paper presents a review of the neutral sizing with alkyl ketene dimmer, AKD s property, its sizing mechanism , its hydrolization, and its emulsification.

介绍了AKD的性质，施胶机理，水解及其乳化和影响AKD施胶的因素。

In this paper, the cationic polymers prepared by our lab were used as emulsifiers to emulsify alkyl ketene dimmer wax, and PAC was used to increase the charge of the emulsion. The optimum emulsifying conditions was determined as the follows emulsifying time was 8 min, the emulsifying temperature was 60℃, the stirring speed was 20000 r/min, and usage of the emulsifier was 4%.

用实验室自制阳离子聚合物复合乳化剂乳化AKD，加入一定量的聚合氯化铝用作电荷增强，对AKD 的乳化工艺进行了研究，确定了最优乳化时间为8 min，乳化温度为60℃，搅拌速度为20000 r/min，乳化剂用量为4%。

Because after the selection the endometriosis conservative surgery still the painful menstruation case of illness 100 examples, stochastically divided into the treatment group 68 examples and the control group 32 examples, took orally the Chinese native medicine preparation separately and is pregnant three ketene capsule for 3 months.

选取因子宫内膜异位症保守性手术后仍痛经的病例100例，随机分为治疗组68例和对照组32例，分别口服中药制剂及孕三烯酮胶囊3个月。

In this paper, a cyclic ketene acetal of 2-methylene-1,3-dioxepane was prepared. And then biodegradable SAP with C-O-C in the backbone was synthesized by Ring-Opening copolymerization of MDO with acrylic acid.

目前市场上使用的高吸水性树脂几乎都是聚丙烯酸类，但其生物分解性差，易造成地下水及土壤环境污染，可生物降解高吸水性树脂的制备引起了学术界极大的关注。

In chapter four molecular modeling method is employed to comparatively study five S-allyl γ-hydroxy ketene dithioacetals reactions of Thio-Claisen rearrangement with and without zeolite catalysts.

第四章用分子模拟途径研究了在有、无分子筛催化条件下五种丙烯基羟基乙烯酮二硫代乙缩醛Thio-Claisen重排反应。

In the end, a Novel and facile method has been used to synthesize functionalized cyclopentadienes by Nazarov cyclization ofα-alkenoyl ketene dithioacetals under Vilsmeier conditions.

从合成的α-烯酰基二硫缩烯酮类化合物出发，经过Vilsmeier试剂作用下的Nazarov环合反应，合成了官能化环戊二烯类化合物。

Keywords ketene;isopropenyl acetate;esterification;strong acidic cation-exchange resin;fine chemical intermediates

乙烯酮；乙酸异丙烯酯；酯化反应；强酸性离子交换树脂；精细化工中间体

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。