异辛醇催化氧气氧化合成异辛酸的研究

大蒜破瓣机摘要

异辛酸（又称2-乙基己酸）是一种重要的精细化学品，广泛用于涂料、油墨、塑料、医药、农药、国防等领域。异辛酸是环烷酸的替代化学品，大部分用于生产异辛酸的金属盐。通常情况下，异辛酸盐的性能优于环烷酸盐，用途更加广泛。目前，合成异辛酸的原料主要有异辛烯醛、异辛醛、异辛醇。异辛烯醛、异辛醛为有机中间产品，产品性能不稳定，在工业上没有规模生产。由异辛醇合成异辛酸的方法主要有两类：一是采用高锰酸钾、重铬酸钾、硝酸等强氧化剂，产品组成复杂、污染十分严重；二是先采用氢氧化钠脱氢氧化得到异辛酸钠，然后再进行酸化制取异辛酸，工艺路线长，危险性大，腐蚀、污染严重。上述两类方法都不是制取异辛酸的理想合成方法。工业上，生产异辛醇的工艺成熟，成本不断降低，且异辛醇产能已达饱和状态，研究异辛醇氧化合成异辛酸已成为当今研究异辛醇在化工领域新用途的热点之一。

本研究以异辛醇为原料，采用绿的催化剂、氧气直接氧化方法制取异辛酸。分别研究了以磷钨酸季铵盐、二氧化硅负载磷钨酸季铵盐、铁系和铝系尖晶石为催化剂，采用氧气直接氧化，在较温和的条件下制取异辛酸。实验研究了氧化反应的影响因素及工艺过程。研究了磷钨酸季铵盐催化氧气直接氧化制取异辛酸的反应机理。

以复分解法合成的磷钨酸季铵盐为催化剂，异辛醇氧气直接氧化制取异辛酸的适宜条件为：磷钨酸与十

六烷基三甲基氯化铵的摩尔配比1：3、催化剂用量3%、反应温度85℃、反应时间18h，异辛酸的收率高达72%；采用溶胶-凝胶法制备的二氧化硅负载磷钨酸季铵盐作催化剂，反应条件为：30%负载量的磷钨酸季铵盐用量为4%、反应温度85℃、反应时间24h，异辛酸的收率达到59%，负载型的磷钨酸季铵盐催化剂可以重复使用；采用溶胶-凝胶法制备的铁系尖晶石作催化剂，在固定床反应器中考察了催化剂性能，异辛醇氧气氧化合成异辛酸的工艺条件为：反应温度为320℃、压力0.4MPa、空速3h-1，异辛酸的收率达33%。

利用IR、UV、XRD、BET、SEM、粒度等分析仪器对催化剂进行了表征。采用GC、IR对氧化产物进行了分析检测。

关键词：异辛酸，异辛醇，氧气氧化，绿工艺，磷钨酸季铵盐

Abstract

Isooctanoic acid (also known as 2-ethylhexanoic acid) is an important fine chemical, widely used in coatings, inks, plastics, drugs, pesticides, defence and other fields. Isooctanoic acid is an alternative chemical to naphthenic acid, and most of which is used to produce isooctanoic acid. Usually, isooctanoate’s performance is better than naphthenate and its application is more extensive. At present, the raw materials of isooctanoic acid synthesis are isooctylene aldehyde, isooctyl aldehyde,

isooctanol. Isooctylene aldehyde and isooctyl aldehyde are organic intermediate products, which have unstable performances. Therefor, there is no mass production in industry. There are two main methods for the synthesis of isooctanoic acid from isooctanol: First, by strong oxidizer, such as potassium permanganate, potassium dichromate and nitric acid, the composition of product is complex and the pollution is very serious; Second, the dehydrogenation of sodium hydroxide to sodium isooctanoate firstly, and then isooctanoic acid was prepared by acidification. The process route is long, dangerous, corrosive and heavily polluted. These methods are not ideal synthetic method for the preparation of isooctanoic acid. The production process of isooctanol is mature, low cost, and production capacity has reached the saturation state. The study synthesis of isooctanoic acid by oxidation of isooctanol is one of the hotpots in chemical field.

In this study, isooctanol was used as raw material, oxygen direct oxidation synthetic isooctanoic acid with the use of green catalyst. The preparation of isooctanoic acid by the direct oxidation of oxygen under mild conditions, and by using quaternary ammonium phosphotungstate, silica-supported quaternary ammonium phosphotungstate and iron spinel as catalyst were studied respectively. The experiment study influencing factors and the process of oxidation reaction, and reaction mechanism of direct oxidation of isooctanoic acid by quaternary ammonium phosphotungstate.

Study on the preparation of quaternary ammonium phosphotungstate by double decomposition and using it as catalyst, oxygen direct oxidation to synthesize isooctanoic acid, the optimal conditions for preparation of isooctanoic acid: mole ratio of phosphotungstic acid and cetyltrimethylammonium chloride was 1:3, the amount of catalyst 3%, reaction temperature of 85℃, reaction time of 18h and the high yield of isooctanoic acid up to 72%;

With silica-supported quaternary ammonium phosphotungstate by sol-gel method, as a kind catalyst, reaction conditions:the supported amount of 30%, reaction time was 24h and the yield of isooctanoic acid up to 59%. The silica-supported quaternary ammonium phosphotungstate was reused; With iron spinel by sol-gel method, as catalyst, the performance of the catalysts for synthetic isooctanoic acid, was investtigated in a fix bed reactor. The optimal conditions, reaction temperature of 320℃, Reaction pressure was 0.4MPa,space was 3h-1and yield of isooctanoic acid up to 33%.

Catalysts was characterized by IR, UV, XRD, BET, SEM. The oxidation products were analyzed by GC and IR.

Key Words:Isooctanoic acid, Isooctanol, Oxygen oxidation, Green technology, Quaternary ammonium phosphotungstate

摘要 ........................................................................................................................................... I Abstract .................................................................................................................................. II 第1章绪论 . (1)

1.1 环烷酸简介 (1)

1.1.1 环烷酸及其性能 (1)

1.1.2 环烷酸金属盐的应用 (1)

1.1.3 环烷酸现状 (1)

muhdpe合金管

1.2 异辛酸的应用 (2)

1.2.1 在涂料工业中的应用 (2)

1.2.2 在油墨工业中的应用 (2)

1.2.3 在树脂和塑料工业中的应用 (2)

1.2.4 在医药领域中的应用 (3)

1.2.5 在燃料工业中的应用 (3)

1.3 异辛酸的合成方法 (3)

1.3.1 实验室合成法 (3)

过滤饮水机1.3.2 工业合成法 (6)

1.4 醇类化合物选择性氧化与应用研究 (7)

1.4.1 醇类化合物选择性氧化的意义 (7)

1.4.2 醇类化合物选择性氧化的氧化剂 (8)

1.4.3 醇类化合物选择性氧化的催化剂 (8)

1.5 研究内容 (10)

第2章磷钨酸季铵盐催化氧气氧化异辛醇合成异辛酸 (11)

2.1 磷钨酸季铵盐的制备与表征 (11)

2.1.1 实验试剂 (11)

2.1.2 实验装置及仪器 (11)

2.1.3 催化剂的制备原理 (12)

2.1.4 制备过程 (13)

2.1.5 磷钨酸季铵盐的表征 (13)

2.2 磷钨酸季铵盐催化氧气氧化合成异辛酸 (15)

2.2.1 实验原料 (15)

2.2.2 实验仪器与装置 (16)

2.2.3 实验方法 (17)

2.2.4 产物分离和催化剂回收 (17)

2.2.5 产物分析检测 (17)

2.2.6 转化率与收率的计算 (18)

2.2.7 结果与讨论 (18)

2.2.8 产物分析结果 (23)

2.2.9 反应机理的研究 (24)

2.3 小结 (26)

第3章负载型磷钨酸季铵盐催化氧气氧化异辛醇合成异辛酸 (27)

3.1 负载型磷钨酸季铵盐的制备与表征 (27)

环己甲酸

3.1.1 实验药品 (27)

vobu3.1.2 实验装置及仪器 (27)

3.1.3 制备方法的选择 (28)

3.1.4 载体选择 (28)

3.1.5 制备原理 (28)

3.1.6 制备方法 (29)

3.1.7 负载型磷钨酸季铵盐的表征 (29)

锚杆挡墙3.2 负载型磷钨酸季铵盐催化合成异辛酸 (33)

3.2.1 实验药品及试剂 (33)

3.2.2 实验装置及仪器 (33)

3.2.3 实验方法 (33)

3.2.4 产物分离和催化剂回收 (33)

3.2.5 产物分析检测 (33)

3.2.6 转化率与收率计算 (33)

3.2.7 结果与讨论 (33)

3.2.8 产物分析结果 (37)

3.3 小结 (38)

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