2-溴-4-甲基苯酚的合成

2-溴-4-甲基苯酚是合成许多药物及广谱型香料香兰素的重要中间体。常温下,以对甲基苯酚为原料加溴易生成2,6-二溴-4-甲基苯酚,本文在原来工作的基础上,在低温下,通过溴化氧化一步直接合成了2-溴-4-甲基苯酚,产率可达93％并通过红外光谱和核磁共振谱对产物结构进行确证。反应的最佳条件是：反应温度为-5～-10℃,反应时间为4h,搅拌速度为1000r／min,对甲基苯酚与双氧水物质的量比为1：0．85。反应方程式如下：     

溴水与苯酚反应产物的探讨

通过查阅文献和实验探究了苯酚的几种溴代产物在水、苯酚熔液和苯酚水溶液中的溶解性;从有机反应的理论角度探讨了苯酚溴代反应机理及产物的确证,指出苯酚与溴水反应的产物是2,4,6-三溴苯酚。     

对甲基苯酚电催化氧化机理

在无隔膜电解槽中, 利用线性伏安法和恒电流电解法研究了Ti/PbO2电极对于对甲基苯酚氧化的电催化活性, 通过阳极过程中对甲基苯酚及其氧化中间产物的液相色谱测定, 研究了对甲基苯酚电催化氧化降解的机理. 研究结果表明, Ti/PbO2电极能够有效地电催化氧化水溶液中的对甲基苯酚, 在25 ℃下, 初始浓度为2 mmol/L的对甲基苯酚溶液, 恒定电流密度为50 mA/cm2, 电解3 h, 对甲基苯酚的转化率为74.32%, 有机碳去除率为61.81%. 对甲基苯酚电氧化降解要经过生成对羟基苯甲醇、对羟基苯甲醛、对羟基苯甲酸、对苯二酚、对苯醌、顺丁烯二酸和草酸, 最终变成CO2的历程, 其中对苯二酚的氧化和顺丁烯二酸的氧化为反应的速控步骤.     

4-取代-2,6-二(羟甲基)苯酚的选择氧化

酚类由于本身容易氧化,仅在非常温和的条件下才能直接使4-取代-2,6-二(羟甲基)苯酚中的羟甲基氧化成醛基。文献报道了用活性二氧化锰可以将2,6-二(羟甲基)-4-甲基苯酚氧化成2-羟基-5-甲基-1,3-苯二甲醛,但要使两个羟甲基中只有一个被氧化却是困难的。文献报道了由芳氧基溴化镁与甲醛作用制备水杨醛类化合物的方法,并认为中间产物是邻羟甲基苯酚的镁盐,后者与甲醛之间通过负氢离子转移的分子间氧化还原反应生成相应     

2-甲基-6-(3-甲基-2-丁烯基)对苯二醌的合成

以邻甲基苯酚为原料,与1-氯-2-甲基-2-丁烯反应生成2-甲基-6-(3-甲基-2-丁烯基)苯酚,然后催化氧化得到目标产物2-甲基-6-(3-甲基-2-丁烯基)对苯二醌。该合成路线简单,易于操作,最终收率51%。     

对甲基苯酚在不同催化剂电极上的电氧化

在无隔膜电解槽中, 利用线性伏安法和恒电流电解法研究了Ti/PbO2、石墨和Pt电极对于对甲基苯酚电氧化的催化活性, 通过电解前后溶液中对甲基苯酚及其氧化中间产物的液相色谱测定, 比较了对甲基苯酚在3种电极上的转化和降解速度, 并讨论了对甲基苯酚电氧化降解的历程和速控步骤. 研究结果表明, Ti/PbO2电极能有效地催化氧化水溶液中的对甲基苯酚, 并将其彻底去除, 电极活性较高; 石墨电极也能够催化氧化水溶液中的对甲基苯酚, 但效果较差; Pt电极在3.0 h的电解时间内, 只能将对甲基苯酚转化成对苯二酚, 而不能将其完全矿化. 对甲基苯酚电氧化降解需要经过对羟基苯甲醇→对羟基苯甲醛→对羟基苯甲酸→对苯二酚→对苯醌→顺丁烯二酸→草酸, 最终生成二氧化碳和水的历程. 当以Ti/PbO2作阳极时, 对苯二酚转化为对苯醌和顺丁烯二酸转化为草酸两步反应为较慢的速控步骤; 当以石墨作为阳极时, 对苯二酚转化为对苯醌的反应为速控步骤.     

镁铝类水滑石对邻、间、对甲基苯酚的吸附

采用液相非稳态共沉淀法制备了镁铝类水滑石（Mg-Al HTlc）,并研究了邻、间和对甲基苯酚在Mg-Al HTlc上的吸附行为。 结果表明,邻、间和对甲基苯酚在Mg-Al HTlc上的吸附等温方程均符合Freundlich吸附等温式;吸附动力学均符合准二级动力学方程;在实验范围内,Mg-Al HTlc对三者的吸附量为：对甲基苯酚＞邻甲基苯酚＞间甲基苯酚;在pH值5.00~13.00范围内,三者的吸附量均随pH值的增加先增大后减小、随温度升高和电解质（NaCl）浓度的增大而增大。 探讨了吸附机理和苯环上甲基取代基位置对吸附的影响。     

金属铜(Ⅱ)配合物催化2,6-二甲基苯酚氧化偶合反应的动力学研究

 合成了四种金属铜(Ⅱ)-四氮配合物,并用初始速率法研究了25 ℃时四种配合物催化H2O2氧化偶合2,6-二甲基苯酚生成3,3′,5,5′-四甲基联苯二醌反应的动力学. 结果表明此偶合反应符合Michaelis-Menten酶催化动力学,并由此获得了反应在不同配合物和不同pH值情况下的动力学参数k2和Km. 研究还发现不同的铜配合物其催化活性有不同的最适pH,具有较好电子共轭效应和合适刚柔性结构的铜配合物更有利于反应的进行. 对此催化反应的动力学机理研究发现,铜配合物的一级酸式电离中间物种是反应的主要催化活性物种. 质谱分析表明,此类铜配合物都能催化2,6-二甲基苯酚进行C-O偶合反应生成不同聚合度的高分子.     

α-甲基苯乙烯与苯酚的烷基化反应研究

分别以磷酸-冰醋酸,苯酚铝,阳离子型交换树脂及络合物为催化剂,研究了α-甲基苯乙烯与苯酚的烷基化反应。用GC测得各组份的含量,结果表明,用不同的催化剂,可生成不同含量的烷基化产物。烷基化产物以4-枯基苯酚,2,4-二枯基苯酚及2,4,6-三枯基苯酚为主。     

二氧化硅负载磷钨酸铵催化苯酚氧化溴代反应

以溶胶-凝胶法制备的二氧化硅负载磷钨酸铵为催化剂,溴化钾为溴源,双氧水为氧化剂,冰醋酸为溶剂,实现了苯酚的催化氧化溴代反应。 探讨了催化剂负载量、催化剂用量和反应时间等反应参数对氧化溴代反应的影响。 结果表明,溶胶-凝胶法制备的负载磷钨酸铵仍具有典型的Keggin结构;在室温的温和条件下,该催化剂表现出较强的催化苯酚氧化溴代反应活性和较高的对溴苯酚选择性,在实验优化条件下,苯酚转化率达到95.4%,对邻比达到3.2;而且催化剂易回收,重复4次使用后,催化活性有所降低,苯酚转化率为87.4%,对邻比为1.6。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...