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1.
邻溴对甲基苯酚的合成   总被引:1,自引:1,他引:0  
邻溴对甲基苯酚是合成药物和香料的重要中间体,其合成方法有多种。以对甲基苯酚和单质溴为原料,以四氯化碳为溶剂,在冰盐水温度下,缓慢滴加溴并快速搅拌,进行液相溴化反应,产物经色.质谱分析确定为邻溴对甲基苯酚。较好的反应条件为:n(单质溴):n(对甲基苯酚)=1.1,反应温度-l5~-10℃,反应时间8h。产品纯度99%,产率71%。  相似文献   

2.
The mineralization of acidic aqueous solutions with 230 and 115 ppm of herbicide 3,6-dichloro-2-methoxybenzoic acid (dicamba) in 0.05 M Na2SO4 of pH 3.0 has been studied by electro-Fenton and photoelectro-Fenton using a Pt anode and an O2-diffusion cathode, where oxidizing hydroxyl radicals are produced from Fenton's reaction between added Fe2+ and H2O2 generated by the cathode. While electro-Fenton only yields 60-70% mineralization, photoelectro-Fenton allows a fast and complete depollution of herbicide solutions, even at low currents, by the action of UV irradiation. In both treatments, the initial chlorine is rapidly released to the medium as chloride ion. Comparative electrolyses by anodic oxidation in the absence and presence of electrogenerated H2O2 give very poor degradation. The dicamba decay follows a pseudo-first-order reaction, as determined by reverse-phase chromatography. Formic, maleic and oxalic acids have been detected in the electrolyzed solutions by ion-exclusion chromatography. In electro-Fenton, all formic acid is transformed into CO2, and maleic acid is completely converted into oxalic acid, remaining stable Fe3+-oxalato complexes in the solution. The fast mineralization of such complexes by UV light explains the highest oxidative ability of photoelectro-Fenton.  相似文献   

3.
杨兴锴 《河北化工》2004,27(6):49-50
探讨了4-甲基苯酚与异丁烯用浓硫酸作催化剂选择性合成2-叔丁基-4-甲基苯酚,分析各种影响反应进行的因素及不同反应条件对产品的收率、原料转化率的影响,从而确定最佳的工艺合成条件:催化剂用量为3%(wt),反应时间为47 min,反应温度为70℃,补充反应时间为30 min。平均收率可达90.1%,选择性可达92.8%。  相似文献   

4.
2,6-二甲酰基对甲苯酚的合成   总被引:2,自引:1,他引:2  
提出了一种用活性纳米γ—MnO2作氧化剂合成2,6—二甲酰基对甲苯酚的新方法。活性纳米γ—MnO2的氧化转化率高。  相似文献   

5.
Solutions of the azo dyes Disperse Red 1 (DR1) and Disperse Yellow 3 (DY3), commonly used in the Chilean textile industry, in 0.1 mol dm−3 Na2SO4 and 0.5 mmol dm−3 Fe2+ of pH 3.0 were comparatively degraded by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF) using a 2.5 dm3 recirculation flow plant containing a BDD/air-diffusion cell coupled with a solar photoreactor. Organics were oxidized in EF with hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between electrogenerated H2O2 and added Fe2+. The oxidizing power of SPEF was enhanced by the additional production of hydroxyl radicals from the photolysis of Fe(III) hydrated species and the photodecomposition of Fe(III) complexes with intermediates by UV light of solar irradiation. Total decolorization, complete dye removal and almost overall mineralization for both dye solutions were only achieved using the most potent SPEF process, yielding higher current efficiencies and lower energy consumptions than EF. Final carboxylic acids like pyruvic, acetic, oxalic and oxamic were detected during the SPEF treatments. NO3 ion was released as inorganic ion. The use of a solution pH of 2.0–3.0 at 50 mA cm−2 was found preferable for SPEF. Synthetic textile dyeing solutions containing the dyes were treated under these conditions yielding lower decolorization rate, slower dye removal and smaller mineralization degree than only using 0.1 mol dm−3 Na2SO4 due to the parallel oxidation of organic dyeing components. However, lower energy consumptions were obtained by the destruction of more amounts of total organic carbon, indicating that SPEF is a useful and viable method for the remediation of textile industrial wastewaters with high contents of disperse azo dyes.  相似文献   

6.
以2-氨基-4-氯苯酚为原料。经乙酰化、闭环、硝化、碱解和酸化合成2-氨基-4-氯-5-硝基苯酚,精制品总收率为64%。  相似文献   

7.
The degradation of a 41 mg dm−3 ibuprofen (2-(4-isobutylphenyl)propionic acid) solution of pH 3.0 has been comparatively studied by electrochemical advanced oxidation processes (EAOPs) like electro-Fenton, UVA photoelectro-Fenton and solar photoelectro-Fenton at constant current density. Experiments were performed in a one-compartment cell with a Pt or boron-doped diamond (BDD) anode and an O2-diffusion cathode. Heterogeneous hydroxyl radical (OH) is generated at the anode surface from water oxidation, while homogeneous OH is formed from Fenton's reaction between Fe2+ and H2O2 generated at the cathode, being its production strongly enhanced from photo-Fenton reaction induced by sunlight. Higher mineralization is attained in all methods using BDD instead Pt, because the former produces greater quantity of OH enhancing the oxidation of pollutants. The mineralization rate increases under UVA and solar irradiation by the rapid photodecomposition of complexes of Fe(III) with acidic intermediates. The most potent method is solar photoelectro-Fenton with BDD giving 92% mineralization due to the formation of a small proportion of highly persistent final by-products. The effect of Fe2+ content, pH and current density on photoelectro-Fenton degradation has been studied. The ibuprofen decay always follows a pseudo-first-order kinetics and its destruction rate is limited by current density and UV intensity. Aromatics such as 1-(1-hydroxyethyl)-4-isobutylbenzene, 4-isobutylacetophenone, 4-isobutylphenol and 4-ethylbenzaldehyde, and carboxylic acids such as pyruvic, acetic, formic and oxalic have been identified as oxidation by-products. Oxalic acid is the ultimate by-product and the fast photodecarboxylation of its complexes with Fe(III) under UVA or solar irradiation explains the higher oxidation power of photoelectro-Fenton methods in comparison to electro-Fenton procedures.  相似文献   

8.
任志强  秦丙昌 《广东化工》2014,(8):33+36-33,36
对4-甲基-3-溴苯酚的合成进行了改进:简化了溴化反应的后处理步骤,解决了还原反应的后处理中Sn(OH)2胶体沉淀难以破坏的问题,改进了重氮盐水解反应的操作方法。按照改进的方法,以4-硝基甲苯为起始原料经4步反应合成目标化合物,总收率为53%。  相似文献   

9.
王静  桑俊利 《天津化工》2009,23(5):32-34
以对氯磷硝基苯胺、甲基丙烯酸为原料,二甲苯为溶剂,P20,为催化剂合成得到N-(4-氯-2-硝基苯基)-2-甲基丙烯酰胺,产率为62%。研究了反应物的物质的量比、催化剂用量和反应时间对合成N-(4-氯-2-硝基苯基)-2-甲基丙烯酰胺的影响,得到最佳反应条件。并对产品进行了IR和NMR的结构鉴定。  相似文献   

10.
以氯乙酸和硫脲为原料合成了2-亚氨基噻唑-4-酮,再与Vilsmeier试剂作用,经缩合水解得到2-氨基4-氯-5-醛基噻唑,总收率达到86%。  相似文献   

11.
The electro-Fenton (EF) and photoelectro-Fenton (PEF) degradation of solutions of the beta-blocker propranolol hydrochloride with 0.5 mmol dm−3 Fe2+ at pH 3.0 has been studied using a single cell with a boron-doped diamond (BDD) anode and an air diffusion cathode (ADE) for H2O2 electrogeneration and a combined cell containing the above BDD/ADE pair coupled in parallel to a Pt/carbon felt (CF) cell. This naphthalene derivative can be mineralized by both methods with a BDD anode. Almost overall mineralization is attained for the PEF treatments, more rapidly with the combined system due to the generation of higher amounts of hydroxyl radical from Fenton's reaction by the continuous Fe2+ regeneration at the CF cathode, accelerating the oxidation of organics to Fe(III)-carboxylate complexes that are more quickly photolyzed by UVA light. The homologous EF processes are less potent giving partial mineralization. The effect of current density, pH and Fe2+ and drug concentrations on the oxidation power of PEF process in combined cell is examined. Propranolol decay follows a pseudo first-order reaction in most cases. Aromatic intermediates such as 1-naphthol and phthalic acid and generated carboxylic acids such as maleic, formic, oxalic and oxamic are detected and quantified by high-performance liquid chromatography. The chloride ions present in the starting solution are slowly oxidized at the BDD anode. In PEF treatments, all initial N of propranolol is completely transformed into inorganic ions, with predominance of NH4+ over NO3 ion.  相似文献   

12.
王倩煜  庄惠生  于颖彦 《化学试剂》2012,34(6):485-488,554
针对4-甲基苯酚(4-MP)的结构特点及半抗原设计原则,选择对羟基苯丙酸(34-HPA)作为半抗原,通过活化酯法与牛血清白蛋白(BSA)偶联合成人工免疫原,免疫3~4 m的雄性大白兔,制得多克隆抗体效价为1∶204 800。同时采用混合酸酐法合成半抗原-卵清蛋白(OVA)偶联物作为包被原,以4-MP为竞争的抗原,建立间接竞争ELISA检测方法。实验结果表明,理想工作条件为:包被原浓度1.05μg/mL,抗体稀释倍数1∶12 800,酶标二抗稀释倍数1∶1 000,0.1%明胶封闭1.5 h,竞争时间与酶标二抗反应时间均为1.0 h。4-甲基苯酚在δ1.0×10-2~1.0×103的范围内呈线性相关,得标准曲线方程y=-12.76x+66.66,最低检测限δ0.02,板内差异为7.0%,板间差异为8.4%。  相似文献   

13.
2-氯-5-(4-氯-1-甲基-5-三氟甲基-1H-吡唑-3-基)-4-氟苯甲醛是合成除草剂的中间体,它可以通过以下2步反应制得:首先,4-氯-3-(4-氯-2-氟-5-甲基苯基)-1-甲基-5-三氟甲基-1H-吡唑在乙酸/乙酐混合溶剂中用三氧化铬氧化,然后,在乙醇/水混合溶剂中,用碳酸氢钠催化水解得目的的产物,2步反应总收率达到71.6%。  相似文献   

14.
2-氯-3-氨基-4-甲基吡啶的合成   总被引:6,自引:0,他引:6  
许青青  陈中元 《应用化工》2005,34(2):72-75,78
2 氯3 氨基4 甲基吡啶是合成抗艾滋病药物奈韦拉平的关键医药中间体。对其合成方法进行了全面的综述,并指出以4,4 二甲氧基2 丁酮和丙二腈为原料的合成方法工艺简单,生产成本低,具有较大的开发价值。  相似文献   

15.
研究了用HPLC分析抗氧剂1520(2,4-二(正辛硫基亚甲基)-6-甲基苯酚)含量的方法。采用Waters 2695-2996型高效液相色谱仪、Waters SunFireTMC18色谱柱,以甲醇和水混合溶剂(体积比95∶5)做流动相,流速1.0mL/min,紫外检测波长285nm的条件时,样品中的各组分达到较好的分离效果。2,4-二(正辛硫基亚甲基)-6-甲基苯酚质量浓度在0.2~2.0mg/mL范围内与色谱峰面积(A)呈线性关系,线性回归方程为A=140.17c-28.74,相关系数R2=0.995 4。采用外标法单点校正峰面积定量,对抗氧剂1520标准溶液测定的回收率为99.96%~100.24%。  相似文献   

16.
环戊口恶草酮是一种新型口恶唑啉二酮类除草剂,N-(2-氟-4-氯-5-环戊氧基苯基)氨基甲酸乙酯是合成该除草剂的重要中间体之一.本文以5-硝基-2-氯-4-氟苯酚为原料,经催化加氢还原、烷基化反应等合成了N-(2-氟-4-氯-5-环戊氧基苯基)氨基甲酸乙酯.该方法操作简便,四步总收率达56.7%.  相似文献   

17.
由4-氯吡啶通过自由基酰化反应合成4-氯-2,6-二乙酰基吡啶和4-氯-2,6-二丙酰基吡啶,方法简单,产率较文献方法高,分别达到25.7%和51.7%。  相似文献   

18.
分别采用间氯甲苯、N-间甲苯基乙酰胺、间甲基苯胺和2-甲基-4-氯苯甲腈等不同的起始原料来合成标题化合物,并探讨了各条反应路线的条件、收率及工业生产的可行性,从而确定了以N-间甲苯基乙酰胺为原料的合成路线是一条较佳工业合成工艺路线,其总收率为32.3%.  相似文献   

19.
The oxidation of carbon nanotubes (CNTs) by hydroxyl radical produced by pulsed O2 plasma in a gas-liquid hybrid discharge reactor was conducted with the goal of enhancing their solubility and improving the yield of H2O2 in electro-Fenton. Data from the characterization experiments showed that oxygen bearing groups (COH, COO, COOH, CO) were formed on the surface of CNTs. The possible mechanism indicated that introduction of oxygen bearing groups onto CNTs could be attributed to the attacks by hydroxyl radical. The oxidized CNTs were easily dispersed in ethanol. The H2O2 yield on the original CNTs was 102 mg/L at −0.85 V after 90 min; in contrast, H2O2 yield on CNTs-15 reached 146 mg/L under the same conditions, resulting from the enhancement of the accessibility of O2 on CNTs. In the electro-Fenton, the removal of methyl orange on the original CNTs was around 40%, and it increased to 95% on CNTs-15.  相似文献   

20.
本文提出了以对氯邻硝基苯酚为原料,使用Raney Ni催化加氢制备对氯邻氨基苯酚,并采用双氰胺为脱氯抑制剂,产品收率达到92.3%。  相似文献   

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