醋酸

Novozym 435 was used for the synthesis of vitamin A plamitate. The influences of solvent, the molar ratio of substrates, the reaction temperature and time, and the water concentration were optimized and the best result was obtained by interesterification from 0.200 g vitamin A acetate and 0.468 g palmitic acid, at 30℃, in 10 mL hexane, containing 0% of water, with 10% of lipase(mass ratio, immobilized lipase to vitamin A plamitate). In these conditions, 75% of vitamin A acetate was converted into vitamin A plamitate. The immobilized lipase was reused about 6 batches.

对催化合成维生素A棕榈酸酯反应的脂肪酶和反应介质比较，同时对影响合成维生素A棕榈酸酯反应的因素（温度、初始水含量、底物摩尔比、反应时间和酶量等）进行了探讨，优化了反应条件：在10 mL不含水分的正己烷中，0.200 g 维生素A醋酸酯和0.468 g棕榈酸在酶量为10％（指固定化酶与维生素A醋酸酯的质量比）的固定化脂肪酶催化下，在 30℃、190 r/min下反应6 h，转化率可以达到75%，固定化酶可连续使用6次以上。

Major Products: acetic acid, vinyl acetate monomer and value-added derivatives

主要产品：醋酸，醋酸乙烯单体，增值衍生品

Major Products: acetic acid, vinyl acetate monomer and value-added derivatives

重要产品：醋酸，醋酸乙烯单体，增值衍生品

We are also the world's largest producer of acetyl products, including acetic acid, vinyl acetate monomer and polyacetal and a leading global producer of high-performance engineered polymers used in consumer and industrial products and designed to meet highly technical customer requirements.

公司在其主要产品市场上拥有首屈一指的市场地位，是世界上最大的乙酰基产品制造商之一，产品包括醋酸、醋酸乙烯和聚甲醛，公司在聚合物领域内也具有世界领先地位。

In this paper, the antiseptic effect of the complex form of both Calcium Propionate and Sodium Dehydroacetate and the complex form of Calcium Propionate ,Sodium Dehydroacetate and Potassium Sorbate in bread have been studied .

研究了丙酸钙与脱氢醋酸钠两者复配形式、丙酸钙与脱氢醋酸钠和山梨酸钾三者复配形式对面包的防腐效果。

In recent years, more and more microbiologists and medical workers have paid much attention to vinegar and made some progress in primary studies.

在高产醋酸菌株的研究中，筛选得到了高产醋酸的12号菌株，并对其进行了紫外线—氯化锂复合诱变。

There were 2 types of tasks in the experiment. In one task, only isoamyl acetate was used as odorant. In the other task, to avoid possible decreased olfactory attention, vanillin was given before each presentation of isoamyl acetate.

采用事件相关设计，每名受试者完成两段嗅觉刺激任务，一个是单一醋酸异戊酯刺激，另一个在醋酸异戊酯刺激前给予香草醛，采用fMRI分析嗅觉皮层的活动。

In addition, 65% ee was obtained for 1, 3-dimethylprop-2-enyl acetate. Interestingly, the reactivities of these ligands are all very high.

对于1， 3-二苯基烯丙基醋酸酯的烷基化和胺化反应， ee 值最高分别为93%和98%，此外，在对1， 3-二甲基烯丙基醋酸酯的烷基化反应中 ee 值最高也可达65%。

Ammonium acetate buffer solution adjusted to pH 4.3 with glacial acetic acid; methanol.

醋酸铵缓冲溶液调节pH 4.3和冰川醋酸；(2)甲醇。

A method for simultaneous determination of oxytetracycline, tetracycline, chlortetracycline and choramphenicol in seafood was successfully developed using high performance liquid chromatography with ammonium acetate/water and acetonitrile as the mobile phase. The results showed that the four antibiotics were well separated under the optimum conditions, with the limits of detection being 32 μg/kg for oxytetracycline, 15 μg/kg for tetracycline, 23 μg/kg for chlortetracycline, and 19 μg/kg for choramphenicol. The recovery of standard additions was 76~92% and the relative standard deviation was 0.8-4.5%. The method is rapid, sensitive, accurate and reliable and can be applied in the analysis of antibiotic residues in seafood.

建立了同时检测海产品中土霉素、四环素、金霉素、氯霉素残留的高效液相色谱分析方法，以醋酸铵-醋酸/水缓冲液和乙腈作为流动相，通过二元梯度洗脱，使四种抗生素获得了较好的分离，以基线噪音的3倍计算，土霉素、四环素、金霉素、氯霉素最低检出浓度分别为32μg/kg、15μg/kg、23μg/kg、19μg/kg，在添加浓度范围内，四种抗生素的加标回收率为76~92%，相对标准偏差为0.8~4.5%，该方法快速、灵敏、准确，可靠性高，可用于海产品中抗生素残留的色谱分析。

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。