碱性介质中对硝基芳香醚的醚键稳定性研究

设计合成了对硝基苯乙醇、对硝基苯氧乙酸、对硝基苯氧丙酸、对硝基苯氧丁酸、对硝基苯丁醚等一系列的对硝基芳香醚,并以它们作为研究对象,对碱性介质中芳醚键的稳定性进行了研究。发现了对硝基苯氧丙酸亲核取代的异常情况,推测是分子内邻基参与的亲核取代反应。     

硝基苯氧乙酸和1,4—二羟乙基苯二醚制备方法的改进

用过量的氯乙酸或氯乙醇,反应的pH值控制为9～10,可将硝基苯氧乙酸的产率从50%～60%提高到85%～92%,1,4-二羟乙基苯二醚的产率可达80%。     

碱性阶段起始F/U配比对UF最终结构影响的~(13)C-NMR研究

采用两种工艺[如传统工艺(记为A工艺)、低起始n(甲醛或F)∶n(尿素或U)比例工艺(记为B工艺)]合成脲醛树脂(UF),并用定量13C-NMR(核磁共振碳谱)法跟踪检测UF的结构变化。研究结果表明:当碱性阶段起始n(F)∶n(U)≥2.0∶1.0时,A工艺合成的UF最终结构中亚甲基醚键含量比B工艺高11%。这是由于前者在碱性缩聚阶段中醚键生成占优势,而后者因亚甲基桥键生成参与竞争反应而使醚键含量下降,并且两者在该阶段醚键含量差异贯穿整个树脂的合成过程中。由于空间位阻效应,碱性阶段N,N′-二羟甲基脲间的反应主要生成醚键,而含游离氨基的一羟甲基脲自聚或与其他羟甲基化合物的缩聚可生成亚甲基桥键。     

乙氧氟草醚同分异构体杂质的分离纯化与鉴定

采用硅胶柱层析法和半制备液相色谱法对乙氧氟草醚粗品中的乙氧氟草醚同分异构体杂质进行分离制备.根据红外光谱、元素分析、质谱和核磁共振数据,推断其结构为乙氧氟草醚的同分异构体,化学名称为2-氯-1-(3-乙氧基-4-硝基苯氧基)-5-三氟甲基苯.     

零价铁降解多溴联苯醚影响条件的研究

通过离子色谱的方法,利用零价铁对水中的多溴联苯醚进行还原性脱溴,对影响因素进行了研究和探讨。试验结果表明：酸性条件有利于脱溴反应的进行;较高的十溴联苯醚初始浓度有利于脱溴反应的进行;零价铁的粒径越小,其对多溴联苯醚的脱溴效果也越好;温度越高时,多溴联苯醚的脱溴率也越高。研究结果将为利用零价铁渗透式反应墙去除水中的多溴联苯醚污染物提供理论依据。     

新法合成一种肟醚类拟除虫菊酯

本文报道在碱性的条件下,应用异丙基-4-氯苯酮肟与三乙基-3-苯氧基苄基氯化铵反应,合成异丙基-4-氯苯酮肟氧-(3-苯氧基苄基)醚。该化合物是肟醚菊酯中杀虫活性最高的一种。作者还探讨了底物配比、反应时间和反应温度对反应产率的影响。     

碱土金属对CuZrO2催化剂上乙醇制备酮类化合物性能的影响

分别以碱土金属Mg、Ca、Sr和Ba为助剂改性CuZrO2催化剂,并将其用于催化乙醇一步法制备酮类化合物的反应中。结果表明,以碱土金属Ba改性的Ba-CuZrO2催化剂上Cu电子结合能较高,有利于乙醇分子中O—H键断裂形成乙醛,且该催化剂表面乙醛脱附量最大、中强碱性位（晶格氧）碱性最强,明显促进了缩合反应的进行,酮类产物选择性最高,催化剂性能最佳。另外,碱土金属Ba改性的催化剂具有较好的稳定性。     

二苯醚类除草剂乙氧氟草醚

乙氧氟草醚 (ｏｘｙｆｌｕｏｒｆｅｎ)是二苯醚类除草剂 ,国外商品名为果尔。化学名称 :2 -氯 -1 -(3 -乙氧基 -4 -硝基苯氧基 ) -4 -(三氟甲基 )苯。化学结构 :Ｆ3ＣＣｌＯＯＣ2 Ｈ5ＮＯ2乙氧氟草醚是美国罗姆 -哈斯公司开发的含氟二苯醚类除草剂。是一种高效、低毒、低残留、选择性、水旱田兼用、广谱苗前苗后触杀型除草剂。可广泛用于水稻、大豆、棉花、油菜、蔬菜、果树、森林苗圃及其它经济作物防除多种季节性阔叶杂草和禾本科杂草。1　理化性质乙氧氟草醚原药外观为淡黄色至红褐色固体 ,相对密度 1 .4 9(2 5℃ ) ,沸点 (2 50～ 3 0 0 …     

二段硫化条件对均聚氯醚橡胶(CO)性能的影响

研究了二段硫化条件(硫化温度和硫化时间)对均聚氯醚橡胶(CO)基本性能和压缩永久变形性能的影响。结果表明,二段硫化温度越高,硫化时间越长,胶料的拉伸强度和定伸应力越大,硬度越高;而撕裂强度、伸长率、拉断永久变形以及压缩永久变形越小,其中胶料的硬度、拉伸强度、伸长率、压缩永久变形在一定时间后基本上趋于平衡,较好的二段硫化条件为150℃～160℃×3～4h。     

新型环氧树脂添加剂—环氧醚的研制

本文以双酚A型环氧树脂和二乙二醇醚为主要原料,合成了新型环氧树脂添加剂－环氧醚。实验表明,催化剂用量、反应温度和环氧树脂的种类对氧醚的性能有较大的影响。     

The alkyl glycidyl ether as synthetic building blocks

Alkyl glycidyl ether is one of the most useful key materials for industrial applications because the addition reaction of various kinds of nucleophilic reagents to the reactive epoxy bond of the glycidyl ethers has led to glyceryl ether derivatives. Glyceryl ether exhibits many interesting physical and pharmacological properties. The alkyl glycidyl ether can presently be produced at an industrial scale under the phase-transfer catalytic Williamson ether synthesis. We have reviwwed some addition reactions of the alkyl glycidyl ether and possibilities for use as the building blocks for the syntheses of surfactants, pharmaceuticals, etc. that contain glyceryl ether skeletons. Typical examples of alkyl glyceryl ether derivatives include: amino ether as cosmetic material, and isodiglycerin mono- and dialkyl ethers and triglycerin monoalkyl ether as a cosmetic or a pharmacologically useful material, respectively. Another interesting reaction is the rearrangement of the epoxy bond of the alkyl glycidyl ether, which gives alkoxy ketone in a one-pot synthesis.     

Effect of Counter Cation on Alkaline Reaction of β-O-4-Type Substructure in Lignin

This study aimed to clarify the effects of counter cations on the alkaline-induced β-O-4 bond cleavage and further reactions of β-O-4-type substructures in lignin. For this purpose, a non-phenolic β-O-4-type lignin model compound, the erythro isomer of 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)propane-1,3-diol (veratrylglycerol-β-guaiacyl ether), was treated in a 100% water solution or an aqueous methanol, ethanol, or 1,4-dioxane solution containing LiOH, NaOH, or CsOH as an alkaline source at 150?°C. The rates of β-O-4 bond cleavage were in the order of CsOH?>?NaOH?>?LiOH in all solvents. This order can rationally be attributed to the strength of the interactions between HO^– and the counter cations. Because Cs⁺ has the lowest positive charge density among the counter cations and hence interacts with HO^– most weakly, HO^– can exert its reactivity most actively in the reactions using CsOH. We also discuss how the counter cations affect the profile of reaction products.     

Chemical Factors Underlying the More Rapid β-O-4 Bond Cleavage of Syringyl than Guaiacyl Lignin under Alkaline Delignification Conditions

This study aimed to clarify why the β-O-4 bond cleavage of syringyl lignin is more rapid than that of guaiacyl lignin under alkaline pulping conditions. We examined whether or not three chemical factors, acidity of the α-hydroxy group, nucleophilicity of the generated α-alkoxide, and leaving ability of the leaving phenoxide, are different between syringyl and guaiacyl lignins and control the rate of the alkaline-induced β-O-4 bond cleavage, employing dimeric non-phenolic β-O-4-type lignin model compounds (LMCs) and novel methods for estimating these three factors. The results indicated that the α-hydroxy groups of syringyl-type LMCs are relatively more acidic than those of guaiacyl-type and that syringyl nucleus is a better leaving group than guaiacyl nucleus in the β-O-4 bond cleavage. These factors result in the β-O-4 bond of syringyl lignin being more prone to the alkaline-induced cleavage than that of guaiacyl lignin.     

Equilibrium of the simultaneous etherification of isobutene and isoamylenes with ethanol in liquid-phase

The simultaneous etherification of isobutene and isoamylenes with ethanol has been studied using macroreticular acid ion-exchange resins as catalyst. Most of the experiments were carried out over Amberlyst-35. In addition, Amberlyst-15 and Purolite CT-275 were also tested. Chemical equilibrium of four chemical reactions was studied: ethyl tert-butyl ether formation, tert-amyl ethyl ether formation from isoamylenes (2-methyl-1-butene and 2-methyl-2-butene) and isomerization reaction between both isoamylenes. Equilibrium data were obtained in a batchwise stirred tank reactor operated at 2.0 MPa and within the temperature range from 323 to 353 K. Experimental molar standard enthalpy and entropy changes of reaction were determined for each reaction. From these data, the molar enthalpy change of formation of ethyl tert-butyl ether and tert-amyl ethyl ether were estimated. Besides, the chemical equilibrium between both diisobutene dimers, 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene, was evaluated. A good agreement between thermodynamic results for the simultaneous etherification carried out in this work and those obtained for the isolated ethyl tert-butyl ether and tert-amyl ethyl ether systems was obtained.     

A New Model Compound for Studying Alkaline Cellulose Chain Cleavage Reactions

A conformationally rigid cellulose model, the 4′,6′-O-benzylidene derivative of 1,5-anhydrocellobiitol, has been studied to learn more about the mechanisms of chain cleavage reactions under alkaline pulping conditions. Heating the model at 170°C in 2.5N NaOH gave 55% glycon-oxygen (G-O) bond cleavage, and ～45% oxygen-aglycon (O-A) bond cleavage. The amount of observed O-A bond cleavage is significantly higher than that for 1,5-anhydrocellobiitol. The benzylidene model also degraded about ～35% faster than 1,5-anhydrocellobiitol; much of this rate increase can be attributed to a faster rate of O-A bond cleavage for the benzylidene model. The greater amount of O-A bond cleavage in the benzylidene case may be attributable to a more highly substituted glycosyl ring (making the ring a better anion leaving group) and/or to a more conformationally inflexible glycosyl ring. The inflexibility restricts one of the standard G-O bond cleavage mechanisms, namely the S_NicB(2′) mechanism. The results point out the value of choosing appropriate cellulose models.     

Urea-formaldehyde resin structure formation under alkaline condition: a quantitative 13C-NMR study

The urea-formaldehyde (UF) reaction under strong alkaline condition was investigated by using quantitative analysis of ¹³C NMR. The main reaction products were methylolureas and oligomers linked by ether bonds at the beginning stage. With the reaction undergoing, the methylene linkages began to be formed and become predominant at the end point. The conversion of linear methylene ether bond to methylene linkage was also observed. These features were also observed previously for the reaction under acidic condition. It was found that the cyclic ether structure (uron) is much more stable than the linear ether bond, and its stability is second only to the methylene linkages among all the condensed structures. The formaldehyde was consumed in fast Cannizarro reaction under strong alkaline condition, producing considerable amount of methanol, which is the main negative aspect of this condition. With the exception of the differences caused by Cannizarro reaction, the UF production reactions under alkaline and acidic conditions are similar. The pH did not change the thermodynamic nature of the involved reactions, but only changed the competitive relationships of different reactions in kinetics.     

Photoreaction of Phenacyl Aryl Ether Type Lignols

Photoreactions of two dilignols, a trilignol and two tetralignols, all of which contain a phenacyl aryl ether type structure, were investigated. All lignols in ethanol yielded products showing the homolytic cleavage of a phenacyl aryl ether bond in this structure. As to tetralignols photodiscoloration was hardly observed in the absence of air, and the preexistence of a free phenolic hydroxyl groups showed no influence on discoloration even in the presence of air. Photoreaction on a filter paper revealed that main reactions are the recombination of radicals once formed by irradiation and the reaction of radicals with oxygen.     

1-溴-2-对硝基苯氧基乙烷与1,2-二对硝基苯氧基乙烷的分离

以对硝基苯酚与1，2-二溴乙烷反应，合成了有机中间体1-溴-2-对硝基苯氧基乙烷，同时得到另一副产物1，2-二对硝基苯氧基乙烷。对两者的溶解性能进行了简单的探索，并选用石油醚作溶剂，较好地分离并提纯了目标化合物。     

Oligomerization of phenyl glycidyl ether in the presence of ZnCl2

Summary In the presence of ZnCl₂ phenyl glycidyl ether reacts to different products owing to the ring-opening reaction of the oxirane and the cleavage of the ether bond. Using HPLC and offline mass spectrometry most of the reaction products could be identified.A reaction scheme and the supposed reaction mechanism were described involving the formation of chlorine — containing oligomers and low molecular weight by — products resulting from the cleavage of the ether bond of the monomer. Conclusions were drawn for original polyfunctional epoxy resin systems.