查询词典 acid reaction

We discovered that the best stereoselectivity of the Pictet-Spengler (cis/trans=92:8) was obtained, when the reaction of D-tryptophan methyl ester II-33 with piperonal II-34 in acetic acid was catalyzed by benzoic acid at room temperature.

我们发现室温下在冰醋酸中，D-色氨酸甲酯II-33和胡椒醛II-34在苯甲酸催化下，发生Pictet-Spengler反应的立体选择性最高， cis：trans的比例为92： 8。

Synthesis of pyruvic acid from lactic acid by catalytic oxidation with oxygen was studied. The effect of catalyst composition, amount of catalyst and oxygen, reaction temperature and time on product yield was investigated and the optimum conditions were found.

由于丙酮酸的分子中同时具有羰基和羧基两个官能团，因而反应中心多而显出比一般化合物更为重要和特殊的化学性质，已引起越来越多的化学工作者的重视。

Collagenase and 25 m filtration web, and characterized in terms of the expression of different phenotypic markers of osteoclasts and their ability to resorb bone matrix. The phenotypic markers of DCs include the expression of tartrate-resistant acid phosphatase, acid phosphatase, resorption pit assay, reaction to calcitonin and identification of F-actin.

于37oC，5％CO。培养箱中培养1－2小时后，弃培养液：lxPBS清洗数次；0.25％胰酶－EOTA 37℃消化5分钟，加入含川％FBS的a－MEM，经小25tim过滤网过滤；IX PBS清洗末过滤细胞，即得到纯化的破骨样细胞，并进行细胞形态学和分于生物学鉴定。

The study shows that, under the conditions of the concentration of sodium silicic acid being 4%-8%,the pH＜4, and the reaction time being about 5 hour, the stable polysilicic acid is made.

以水玻璃、废盐酸为原料，制备聚硅酸，研究表明：在硅酸钠浓度为4%～8%，pH小于4的条件下，室温熟化5h左右，可制得稳定的聚硅酸。

During the reaction,the bromide component has been converted to catalytically inactive benzylic bromide.In pure acetic acid medium,the "catalyst failure" occurs owing to the formation of benzylic bromide while in acetic acid-water medium,the solvolysis of benzylic bromide by water maintains the catalytic activity to some extent.

反应过程中溴组分会转变为无活性的苄溴，在纯醋酸溶剂中，催化剂会因苄溴的形成而发生催化剂失活现象；在醋酸-水混合溶剂中，由于水对苄溴的溶剂化作用会使苄溴还原为溴离子，一定程度上保持了催化剂活性；并且在一定范围内，含水量的提高有益于生成醛选择性的提高，研究表明，将混合溶剂的初始含水量控制在5-10wt。

This paper discusses the cause of sulphurous acid's difference between oxidation and reduction in the medium of acid and alkali, by applying the principle of normal electrode trend and thermodynamic coincidence reaction .

应用标准电极电势和热力学偶合反应原理对亚硫酸在酸碱介质中氧化、还原性不同的原因进行探讨。

Using stearic acid, hexadecanoic acid,thionyl chloride,triethylamine as raw material, neutral sizing agent AKD was synthesized through three steps of reaction,i.

以硬脂酸、棕榈酸、氯化亚砜、三乙胺为原料，经过酰氯化、缩合和浓缩三步反应合成了中性施胶剂AKD。

The influences of reaction temperature and sulfuric acid concentraction on trichloroethylene conversion and chloroacetic acid recovery have been investigated.

研究了三氯乙烯水解法生产氯乙酸的工艺，并在两种不同的实验方案中考察了反应温度、硫酸浓度对三氯乙烯转化率和氯乙酸收率的影响并确定了适宜的工艺参数，可作为工业化生产研究的基础。

This article analyses some basic conceptions that are comparatively vayue or even wrong wrong in the teaching of middle school chemistry, like the definition of chemical change, the influence of concentration on a chemical reaction , the structure of oxacid,and the acidity of sulfuric acid, the acidity of carbonic acid, and the conversion of allotropic substance.

分析了中学化学教学中的几个比较模糊甚至错误的基本概念，如化学变化、浓度对化学反应速度的影响、含氧酸的结构、硫酸的酸性、碳酸的酸性、热化学方程式的表示法、同素异形体间的转化等，并从大学化学角度加以澄清，以便使大一学生更准确地理解和掌握这些基本概念。

The amphoteric fatliquor of N-amidel- polyethylene polyamine -β-aminopropionic acid types has been synthesized by nature oil and fat reaction with polyethylene polyamine and acrylic acid .

用天然油脂、多乙烯多胺和丙烯酸合成制得N -酰胺基多乙烯多胺-β-氨基丙酸型两性加脂剂，最佳合成条件分两步的反应温度分别控制在 10 0℃及 12 0℃、两步反应时间分别为 2h和 4h ，天然油脂与多乙烯多胺及丙烯酸的物质量的比为 1：0 。

The labia have now been sutured together almost completely.The drains and the Foley catheter come out at the top.

此刻阴唇已经几乎完全的缝在一起了，排除多余淤血体液的管子和Foley导管从顶端冒出来。

To get the business done, I suggest we split the difference in price.

为了做成这笔生意，我建议我们在价格上大家各让一半。