相转移催化合成2,4-二氯苯氧乙酸新工艺研究

以2,4-二氯苯酚和氯乙酸为原料,在碳酸钾作用下筛选相转移催化剂(四丁基溴化铵、四乙基溴化铵和PEG-600)进行醚化反应,制备2,4-二氯苯氧乙酸。所获得的最佳工艺条件是:催化剂选PEG-600/KI为最佳,二氯苯酚和氯乙酸原料物质的量比1∶2,相转移催化剂PEG-600用量为二氯苯酚的6%,KI用量为二氯苯酚量的10%。在此合成条件下,2,4-二氯苯氧乙酸收率达94.2%。     

优化2,4-二氯苯氧乙酸合成的工艺研究

为了优化2,4-二氯苯氧乙酸合成的工艺,以氯乙酸和苯酚为原料,探讨先缩合后氯化合成过程中的最佳反应条件如pH值、温度、时间等条件.结果在制备苯氧乙酸过程中pH值为3、沸水浴时间为17 min,在制备对氯苯氧乙酸滴加H2O2前不需加热,这样得到的2,4-二氯苯氧乙酸产率最高.以氯乙酸和苯酚为原料先缩合后氯化合成2,4-二...     

2,4-二氯苯氧乙酸合成方法的正交试验研究

改进2,4-二氯苯氧乙酸(2,4-D)传统的合成工艺。主要反应不是采取先氯化的方法,而是先以苯酚和氯乙酸缩合后,再用次氯酸钠进行氯化的后氯化法,进而用正交试验,确定了新方法的最佳工艺条件:投料比为苯氧乙酸/g∶冰醋酸/mL=1∶9,次氯酸钠投入量为18mL(滴加),反应温度为冰水浴中进行,酸化至pH<1条件下,产品收率最高。测定了产品的mp IR和NMR,均与文献值相符。     

2,4-二氯苯乙酸合成工艺研究

以2,4-二氯氯苄为原料,经过氰化和碱性水解反应,中间体不纯化分离,得到目标化合物2,4-二氯苯乙酸。总收率达到84.8%,含量99%以上。对反应过程中产生的副产物进行了分离和结构表征。     

十六烷基三甲基溴化铵催化合成对甲苯氧乙酸

利用十六烷基三甲基溴化铵催化氯乙酸和对甲苯酚合成对甲苯氧乙酸,十六烷基三甲基溴化铵具有较高的催化活性,可以加快合成对甲苯氧乙酸。考察了对甲苯酚与氯乙酸摩尔比、催化剂用量、反应时间、反应温度对产率的影响以及催化剂的重复使用性能。反应的最佳条件为:在80℃下,对甲苯酚和氯乙酸的摩尔比为1∶2,催化剂质量为0.2 g,反应时间2.5 h,此反应所得到的对甲苯氧乙酸的产率为51.93%。该催化剂的用量很少,易于回收,并且可以重复使用。     

十六烷基三甲基溴化铵催化合成邻甲苯氧乙酸

利用十六烷基三甲基溴化铵催化氯乙酸和邻甲苯酚合成邻甲苯氧乙酸,十六烷基三甲基溴化铵具有较高的催化活性,可以加快合成邻甲苯氧乙酸。反应过程考察了邻甲苯酚与氯乙酸摩尔比、催化剂用量、反应时间、反应温度对产率的影响以及催化剂的重复使用性能。反应的最佳条件为:在85℃下,邻甲苯酚和氯乙酸的摩尔比为1∶5,催化剂质量为0.3 g,反应时间为3.5h。此反应所得到的邻甲苯氧乙酸的产率为47.07%。该催化剂的用量很少,而且易于回收,并且可以重复使用。     

2,6-二氯苯氧乙酸甲酯合成新工艺

以2,6-二氯苯酚、甲醇钠甲醇溶液和氯乙酸甲酯为原料,合成了2,6-二氯苯氧乙酸甲酯。通过实验优化了反应条件,结果发现,当n（2,6-二氯苯酚）∶n（氯乙酸甲酯）=1∶1.3,在加入氯乙酸甲酯之后蒸出2/3甲醇,回流3.5 h即可完成反应,2,6-二氯苯氧乙酸甲酯的收率可达99%以上。用MS、1H NMR及IR对产物结构进行了表征。     

十六烷基三甲基溴化铵催化合成苯氧乙酸

利用十六烷基三甲基溴化铵催化氯乙酸和苯酚合成苯氧乙酸,十六烷基三甲基溴化铵具有较高的催化活性,可以加快合成苯氧乙酸。反应过程考察了苯酚与氯乙酸摩尔比、催化剂用量、反应时间、反应温度对产率的影响以及催化剂的重复使用性能。反应的最佳条件为:在80℃下,苯酚和氯乙酸的摩尔比为1∶3,催化剂质量为1.5g,反应时间为1.5h。此反应所得到的苯氧乙酸的产率为52.74%。该催化剂的用量很少,而且易于回收,并且可以重复使用。     

2,4-二氯苯甲醛肟氧基乙酸的合成及波谱分析

2,4-二氯苯甲醛肟与氯乙酸在乙腈中反应生成2,4-二氯苯甲醛肟氧基乙酸。探讨了反应溶剂、反应物的物质的量的比、反应时间等因素对产品产率的影响。实验表明:2,4-二氯苯甲醛肟、氯乙酸、氢氧化钠物质的量的比为1∶2∶3.1,反应时间为4 h时,产品的产率达到62.8%。产品进行了红外光谱、1H NMR、紫外-可见光谱分析。     

2,4—二氯苯氧乙酸二甲基烷基硅酯的合成

本文以２，４－二氯苯氧乙酸和三甲基氯硅烷为主要原料，四步合成了四种脂溶性２，４－二氯苯氧乙酸烷基酯。根据红外光谱测定数据，碳氢分析及硅含量的测定，证实了合成的结构。     

固体酸催化合成氯乙酸乙酯

评述了对甲苯磺酸、强酸性阳离子交换树脂、磺化聚氯乙烯树脂、六水三氯化铁、聚氯乙 烯-三氯化铁树脂、氯化聚氯乙烯-三氯化铁树脂、二水氯化亚锡、十二水合硫酸铁铵、硫酸铁-硫代 硫酸钾复盐、四水硫酸铈、一水硫酸氢钠、硫酸氢钾、三氧化二钕、固体超强酸和杂多酸等催化剂催化 合成氯乙酸乙酯的实验结果。结果表明:对甲苯磺酸,强酸性阳离子交换树脂、六水三氯化铁、十二 水合硫酸铁铵、四水硫酸铈、固体超强酸和杂多酸等是合成氯乙酸乙酯的良好催化剂,具有实际应 用价值。     

氨基磺酸催化合成氯乙酸正丁酯

以氨基磺酸作催化剂,通过氯乙酸和正丁醇反应合成了氯乙酸正酯,并探讨了诸因素对收率的影响.实验表明:氨基磺酸具有良好的催化活性,当醇酸配比为1.4∶1(mol),催化剂用量约为氯乙酸质量的2.5%,甲苯为带水剂,反应时间2.5 h,反应温度130~139℃,酯收率可达86.1%.且催化剂可重复使用。     

BSA与CTAB相互作用的荧光光谱研究

在模拟生理条件下,用荧光光谱法研究了十六烷基三甲基溴化铵（CTAB）与牛血清白蛋白（BSA）的相互作用。结果表明：BSA分子中色氨酸和酪氨酸残基具有荧光发射性质,以280nm激发BSA,在341nm处有很强的荧光发射。在加入CTAB后,发现CTAB—BSA强荧光峰的位置蓝移,且荧光强度随着CTAB浓度的增大而明显减弱,说明CTAB对BSA有荧光猝灭现象,猝灭以静态猝灭为主,由Stern—Volmer方程求得CTAB表观猝灭常数Kq=1．469×10^13L·mol^-1·s^-1。得到了CTAB与牛血清白蛋白分子间的结合常数和热力学参数。利用已有的计算方法,建立了相应的计算机程序,使计算结果更合理。通过与常见公式计算的结果进行比较,所建立的方法得到了比较满意的结果。     

2,4-二氯-5-磺酰氨基苯甲酸合成工艺研究

2,4-二氯苯甲酸为原料,经氯磺化、氨解、水解酸化三步反应制备了2,4-二氯-5-磺酰氨基苯甲酸(1)。研究了各步反应的影响因素,确定反应的最佳工艺为:n(氯磺酸)∶n(2,4-二氯苯甲酸)=3.5∶1,反应温度为130～140°C,反应时间为3.5h。得产品2,4-二氯-5-磺酰氨基苯甲酸(2)。n(氨水)∶n(2)=4∶1,10～15°C反应3h,盐酸酸化,得到(1),总收率79.3%,纯度98.7%(HPLC),结构经IR与1H NMR证实。     

The Effect of Sodium Dodecyl Sulfate (SDS) and Cetyltrimethylammonium Bromide (CTAB) on the Properties of ZnO Synthesized by Hydrothermal Method

ZnO nanostructures were synthesized by hydrothermal method using different molar ratios of cetyltrimethylammonium bromide (CTAB) and Sodium dodecyl sulfate (SDS) as structure directing agents. The effect of surfactants on the morphology of the ZnO crystals was investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The results indicate that the mixture of cationic-anionic surfactants can significantly modify the shape and size of ZnO particles. Various structures such as flakes, sheets, rods, spheres, flowers and triangular-like particles sized from micro to nano were obtained. In order to examine the possible changes in other properties of ZnO, characterizations like powder X-ray diffraction (PXRD), thermogravimetric and differential thermogravimetric analysis (TGA-DTG), FTIR, surface area and porosity and UV-visible spectroscopy analysis were also studied and discussed.     

The Effects Of Humic Substances On Pinus Callus Are Reversed By 2,4-Dichlorophenoxyacetic Acid

The reversal of humic matter-induced inhibition of callus growth and metabolism by 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in Pinus laricio. Two forest humic fractions (relative molecular mass (M_r) > 3500), derived from soil under Fagus sylvatica (Fs) and Abies alba (Aa) plantation, were used. Pinus laricio callus was grown for a subculture period (4 weeks) on Basal Murashige and Skoog (MS) medium plus forest humic matters (Fs or Aa), at a concentration of 1 mg C/l, and then was transferred, for an additional four weeks, to a MS medium culture without humic matter, but with different hormones: indole-3-acetic acid (IAA, 2 mg/1) or 2,4-dichlorophenoxyacetic acid (2,4-D, 0.5 mg/1) and/or 6-benzylaminopurine (BAP, 0.25 mg/1). Growth of calluse, glucose, fructose, and sucrose contents, and activities of soluble and bound invertases, glucokinase, phosphoglucose isomerase, aldolase, and pyruvate kinase were monitored. The results show a negative effect of humic fractions on callus growth, due to decreased utilization of glucose and fructose, and decreased activities of glycolytic enzymes. The effects are reversible. Substitution of humic fractions with 2,4-D+BAP or 2,4-D is followed by an increase of glycolytic enzyme activities and, consequently, by the utilization of glucose and fructose that induces a restart of growth. In contrast, the inhibitory effects of humic fractions persist when they are substituted with BAP alone, indicating that only the auxin 2,4-D is capable of reversing the negative effects. A possible competitive action on the auxin-binding site between 2,4-D and the chemical structures in the forest humic fractions is suggested.     

Molecularly Imprinted Polymers Based on Chitosan for 2,4-Dichlorophenoxyacetic Acid Removal

The development of low-cost and eco-friendly materials for the removal of pollutants from water is one of the main modern challenges. For this purpose, molecularly imprinted polymers were prepared under optimized conditions starting from chitosan (CS), chemically or ionically modified with glycidyl methacrylate (GMA) or itaconic acid (ITA), respectively. 2,4-Dichlorophenoxyacetic acid (2,4-D) was used as a template, obtaining the CS_GMA and CS_ITA series. The influence of the template concentration on the MIPs’ (molecularly imprinted polymers) morphology, thermal behaviour and swelling ability, as well as on the 2,4-D removal capacity, were analyzed. The amount of the template used for the imprinting, together with the different permeability of the matrices, were the key factors driving the analyte uptake process. Despite the good performance shown by the non-imprinted CS_GMA sample, the best results were obtained when CS_GMA was imprinted with the highest amount (5%) of template (CS_GMA_5). This system was also more efficient when consecutive adsorption experiments were carried out. In addition, CS_GMA_5 had a desorption efficiency of 90–100% when a low pesticide concentration was used. These findings suggest that the presence of imprinted cavities could be useful in improving the performance of sorbent materials making CS_GMA_5 a possible candidate for 2,4-D removal.     

三氟甲磺酸催化便捷高效合成2,4-滴丁酯除草剂

以2,4-二氯苯氧乙酸与正丁醇为原料,三氟甲磺酸为催化剂,催化合成2,4-滴丁酯,考察了醇酸摩尔比、反应时间及催化剂用量等对反应的影响。结果表明,合成2,4-滴丁酯的最佳反应条件是:正丁醇与2,4-二氯苯氧乙酸的摩尔比为3∶1,催化剂用量为0.2%(占2,4-二氯苯氧乙酸摩尔量),回流反应8 h,在此条件下,酯化率达97.1%。     

羟丙基-β-环糊精及β-环糊精与十六烷基三甲基溴化铵混合体系的电导研究

用电导法研究了十六烷基三甲基溴化铵 (CTMAB)与羟丙基 β 环糊精 (HP β CD)及 β 环糊精 (β CD)混合体系的电导行为。结果表明 ,由于CTMAB与HP β CD或 β CD间形成了包合物 ,使体系电导率增加的幅度减缓。当体系中HP β CD或 β CD的浓度增加时 ,CTMAB的临界胶束浓度 (CMC)增加 ,即转折点后移 ,且HP β CD对CTMAB的CMC转折点后移的影响较 β CD明显