【作者】 陈林；

【导师】 罗和安； 吴剑；

【作者基本信息】 湘潭大学 ， 化学工艺， 2009， 硕士

【摘要】 羟胺及其盐是一类重要的化工中间体,有着广泛的用途,特别是传统上硫酸羟胺、磷酸羟胺等大量地用于酮肟(主要是环己酮肟和丁酮肟)的合成;硝酸羟胺用于核工业和军工业。目前生产羟胺盐的较成熟工艺主要包括催化还原法和电解还原法等。这些生产工艺经多年不断改进,至今仍存在回收催化剂的成本较大或严重危害环境等缺陷。为了寻找新的羟胺盐的生产工艺,本文提出了先由催化氨肟化工艺不使用羟胺盐廉价地生产酮肟,再利用由羟胺肟化的逆反应——酮肟在酸性溶液中水解制取羟胺盐的新思路。研究先着眼于常压下酮肟水解反应的各工艺条件的优化;再转向研究反应的平衡常数等热力学规律;进而提出并尝试了添加溶剂法与减压蒸馏法以加大反应的进度;进一步改进了减压蒸馏工艺。本文研究了常压下酮肟在酸性水溶液中的水解反应,考察了酸的种类、酮肟的种类、加料方式、酸肟比、盐酸浓度、反应时间和反应温度对酮肟转化率以及酮和羟胺盐的选择性的影响,确定了较优的工艺条件为:使用丁酮肟与盐酸反应,一次性加料,盐酸与丁酮肟摩尔比为1.5,盐酸质量浓度为15%,反应温度82℃,反应时间1小时。对应的丁酮肟转化率为7.329%,丁酮选择性为74.45%,盐酸羟胺选择性为96.43%。分别测定了常压73℃和83℃下丁酮肟在盐酸中水解达到平衡时各原料和产物的浓度,算得两个温度下反应的平衡常数分别为0.002033和0.003290,最后得出平衡常数KΘ与随温度T的关系式为:l nKΘ= ?5930/T+10.94。据此可以断定常压下该反应的限度及其可增大的程度都很小。通过分析各种可能促使平衡移动的工艺条件,提出并尝试了添加溶剂法和减压蒸馏法以增大反应进度。结果表明,添加溶剂法在促使原料转化的同时不能有效地减少副反应进行,因此不宜采用;而减压蒸馏法在不断促进原料转化的同时有望减少副反应的进行,但该方法使用负压造成了较大的物料损失。相比于添加溶剂法,减压蒸馏法更具有应用前景。以环己酮肟为反应原料并安装洗气装置以改进减压蒸馏法,取得了一定的效果,反应过程中酮和酮肟的相对损失有所减少,但仍存在酮肟转化率低和酮的回收不足两个问题,还需要进一步优化反应工艺加以解决。更多还原

【Abstract】 As a kind of important chemical intermediates, hydroxylamine and its salts have wide range of applications. Traditionally, hydroxylamine sulfate and hydroxylamine phosphate etc. are mainly used for the synthesis of ketoxime, especially for cyclohexanone oxime and butanone oxime, while hydroxylamine nitrate is applied to nuclear industry and martial industry. Presently, the mature technologies of preparing hydroxylamine salts include catalysed-deoxidization technology and electrolytic-deoxidization technology. Being continually improved for many years, there are still some defects in these technologies, such as high cost of recovering catalyst and being seriously harmful to environment. In order to explore new technology of producing hydroxylamine salts, a new process of hydrolysis reaction, which is the reverse reaction of the traditional synthesizing of ketoxime, is developed in this thesis. The new process use ketoxime as material, which could be low-costly obtained from catalytic ammoximation process.The research firstly focused on optimizing conditions of the reaction at atmospheric pressure. Subsequently, thermodynamics laws of the reaction such as equilibrium constants are studied. In order to break the reaction balance for more ketoxime conversion, technique of adding solvent and vacuum distillation are respectively attempted. Whereafter the vacuum distillation technique was simply improved.In the first part of this thesis, the effect of reaction conditions of ketoxime hydrolysis in acidic solution at atmospheric pressure on the conversion rate of ketoxime as well as the selectivity of ketone and hydroxylamine salt are studied. The conditions include the type of acid and ketoxime, feeding method, the molar ratio of acid to oxime, acid concentration, reaction temperature and reaction time, et al. The optimized conditions of the hydrolysis reaction are listed as follows. Hydrochloric acid has concentration of 15%; the molar ratio of acid to butanone oxime is 1.5; after one-off feeding, react under 82℃for 1hr. Under the above conditions, the conversion rate of butanone oxime reaches 7.329%; the selectivities of butanone and hydroxylamine hydrochloride reach 74.45% and 96.43% respectively.Subsequently, the concentrations of reactants and products in the reaction at atmospheric pressure are singly detected under the temperatures of 73℃and 83℃respectively. The equilibrium constants under the two temperatures reach 0.002033 and 0.003290 correspondingly. Finally the relationship between equilibrium constants( KΘ) and temperature(T ) is educed as follow. lnKΘ= ?5930/T+10.94The result shows that the extent of reaction at atmospheric pressure must be a small value, and remarkable improvement of it is also out of the question.After analysis of various process conditions to break reaction balance, technique of adding solvent and vacuum distillation are proposed. As a result, adding solvent can promote the conversion of raw materials but be hard to avoid side reactions. So it is not suitable for the use. However vacuum distillation can remarkably promote the transformation of raw materials and likely reduce side reactions at the meantime. Vacuum distillation technique has a shortcoming that vacuum will cause much material loss. Anyway, vacuum distillation technique has a better prospect for applications.Vacuum distillation technique is improved to a certain degree by using cyclohexanone oxime as raw material while the device for gas washing is built up. Loss of ketone and ketoxime decreased in the new process.The two core problem of lower conversion rate of ketoxime and lower yield of ketone should to be solved in farther improvement.更多还原