【作者】 廖振宇；

【导师】 马玉龙；

【作者基本信息】 武汉大学 ， 有机化学， 2004， 硕士

【摘要】 对羟基苯甲腈的合成方法文献报道较多，但多数制备方法都需要使用特殊的脱水剂或催化剂，条件苛刻，反应步骤多，环境污染大。本文研究了以气相氨氧化法合成对羟基苯甲腈的新途径，研制了较为适宜的催化剂，分析了各种外界因素对催化剂活性的影响，推测了反应机理。 本文以对羟基苯甲腈的氨氧化为靶反应。研制了氨氧化反应的装置。研究了对羟基苯甲腈的合成和产物的分离、鉴定及定性定量的分析方法。并给出了对羟基苯甲腈的红外光谱、¹H NMR谱图。 对气相氨氧化法合成PHBN的多相催化剂进行了制备和评选。结果表明：（1）硅胶作载体催化活性高。（2）采用物质的量比为n（Mo）：n（Ni）：n（P）：1.19：2.10：1.20的Mo-Ni-P复合氧化物作为催化剂组分时，反应收率较高。（3）加入不同的第三组分（或掺杂）对催化剂的活性有不同的影响。通过评选，选择了Mo-Ni-P负载型氧化物催化剂。 在催化剂的活性评价中，对温度、进料配比及氮气保护等影响因素进行考察，得到的适宜反应条件是：温度385℃，n（p-cresol）：n（NH₃）：n（air）=1：5.25：31.5，对甲基苯酚的空速为12h^-1，p-HBN的产率可达61％（重量），并对反应变量的影响进行了分析。 用红外光谱（IR）、电镜扫描（SEM）、比表面积和孔结构分析、x射线衍射（XRD）、x光电子能谱（XPS）等技术手段对多组分负载型催化剂进行了表征。结果表明：（1）催化剂的活性与其比表面积和孔容有关系。（2）催化剂的活性组分以氧化物MoPO₄形态存在。（3）催化剂在使用过程中有活性物质的流失。（4）活性组分的负载对载体的化学键有一定的影响。（5）催化剂的积炭是其活性降低的主要原因之一。 对对甲酚氨氧化反应机理也进行了探讨，认为对甲酚首先氧化生成对甲苯甲醛中间体，然后在·NH₂自由基或H₂N^-的作用下生成对羟基苯甲腈。更多还原

【Abstract】 A lot of methods of preparing p- hydroxybenzonitrile not only have too many steps but also pollute the environment. The preparation of catalyst for p-hydroxybenzonitrile ammoxidation from SiO2 and mainly component of Mo-Ni-P was studied as well as mechanism of activation adsorption of NH3 on the catalyst surface.It is the target reaction that to prepare p-hydroxybenzonitrile by gas phase ammoxidation ofp-cresol. During studying, the reaction device, the control system and the analysis system of the materials were developed. The method of isolation and the method of the qualitative& quantitative analysis of the reaction products were also studied. And the spectrum of FT-IR, 1H NMR of p-hydroxybenzonitrile were provided.Ammoxidation of p-cresol to p-hydroxybenzonitrile (p-HBN) was studied over a large number of different catalysts. The results showed that (1) Supporters of catalyst had effect catalytic activity markedly and SiO2 is the optimal carrier. (2) The silica supported Mo-Ni-PD n(Mo):n(Ni):n(P)=l. 19:2.10:1.20 oxide catalysts can increase the conversion of p-hydroxybenzonitrile, while the selectivity is still preferable. (3) Different kind of the third components has different influences to the catalysts’ activity. The catalyst contained of molybdenum, phosphor and nickel was selected.The effects of temperature, distribution of porous of catalyst, support and space velocity of the feed gas on catalytic activity were detected. The results showed that the optimal reaction temperature is 385C, n(p-cresol):n (NH3) n (air) = 1:5.25:31.5 D the weight yield of p- hydroxybenzonitrile is 61%. And the influences of these variables were more discussed.The catalysts were characterized by means of FT-IR.BET analysis of specificsurface and pore structure, XRD and XPS. The results showed that(l) The activity of the catalysts is associated with their specific surface area and pore volume. (2) The species of the active component is MoPO4. (3) The active components run off from the catalysts during the reaction. (4) The chemical bonds of supporter were influenced byactive components. (5) Carbon build-up is the prime reason to decrease activity.The mechanism suggested for p-cresol ammoxidation on Mo-Ni-P-O catalysts, a first step oxygen addition to an activated adsorbed p-cresol, and 4-Hydroxy-benzaldehyde like intermediate is obtained, it turn to/7-hydroxybenzonitrile under the attack by adsorbed ammonium ions NH2 or H2N-.更多还原