葡萄糖对苯二酚树脂胶粘剂的合成

以葡萄糖代替甲醛,在碱性条件下合成了葡萄糖对苯二酚树脂胶粘剂。利用红外光谱(IR)及热重分析(TGA)对树脂的结构及热稳定性进行了分析,并通过正交实验获得了该树脂合成的最佳反应条件:pH=13,n(葡萄糖)n∶(对苯二酚)=101,∶反应温度110℃,催化剂用量2.0%,反应时间7h;同时对树脂的固化条件进行了系统研究。     

多壁碳纳米管与聚(2-乙酰基-5-溴噻吩)复合纳米材料修饰玻碳电极同时检测对苯二酚、邻苯二酚和对甲苯酚

该文利用多壁碳纳米管(MWCNTs)和聚(2-乙酰基-5-溴噻吩)复合纳米材料修饰电极,用于同时检测对苯二酚(HQ)、邻苯二酚(CC)和对甲苯酚(PC)。通过循环伏安法(CV),示差脉冲伏安法(DPV)和透射电镜(TEM)表征了该复合纳米材料的电化学性能和表面形貌。结果表明该电极对HQ、CC和PC具有较高的灵敏度和选择性。DPV峰电流与HQ、CC和PC的浓度在1.0×10-5～8.0×10-4mol/L,5.0×10-6～5.5×10-4mol/L和5.0×10-6～7.5×10-4mol/L范围内分别呈良好的线性关系,且检测限分别为3.0×10-6 mol/L,1.7×10-6 mol/L和2.0×10-6mol/L。     

Perkin反应合成肉桂酸

以无水碳酸钾为催化荆，PEG-400为相转移催化剂，对苯二酚为阻聚剂．通过Perkin反应合成肉桂酸，研究了物料比、催化刺用量、PEG-400用量、对苯二酚用量、回流时间对产品产率的影响。最佳反应条件是n(苯甲醛)：n(乙酸酐)：n(碳酸钾)：n(PEG-400)：n(对苯二酚)=1：3：1．1：0．03：0．02．回流溢度180℃时．回流时间1．5h，肉桂酸产率呵达82.4％。     

含钛介孔SiO2 催化剂的合成及其催化性能

分别以廉价硅酸钠与正硅酸乙酯为硅源,通过复合模板剂制备了介孔二氧化硅,并利用吸附相反应技术合成了TiO2/SiO2复合催化剂。用X射线衍射(XRD)、红外谱图分析(FT-IR)等手段对其结构进行了表征,通过苯酚的羟基化反应考察了催化剂的催化性能。     

Liquid-Phase Catalytic Hydroxylation of Phenol Using Cu(II), Ni(II) and Zn(II) Complexes of Amidate Ligand Encapsulated in Zeolite-Y as Catalysts

Copper(II), nickel(II) and zinc(II) complexes of amidate ligand 1,2-bis(2-hydroxybenzamido)ethane(H₂hybe) encapsulated in the super cages of zeolite-Y have been prepared and characterized by spectroscopic studies and thermal as well as X-ray diffraction (XRD) patterns. These complexes catalyze the liquid-phase hydroxylation of phenol with H₂O₂ to catechol as a major product and hydroquinone as a minor product. Considering the concentration of substrate and oxidant, amount of catalyst, temperature of the reaction and volume of solvent, a best-suited reaction condition has been optimized to get maximum hydroxylation. Under the optimized reaction conditions, [Cu(hybe)]-Y has shown the highest conversion of 40% after 6h, which is followed by [Ni(hybe)]-Y with 37% conversion and [Zn(hybe)]-Y has shown the poorest performance with 33% conversion. All these catalysts are more selective towards catechol formation (90%), irrespective of their catalytic performance.     

对苯二酚在金、银纳米粒子修饰的玻碳电极上电化学响应的比较

制备了柠檬酸钠保护的金和银纳米粒子,并用自组装法制备了金和银纳米粒子修饰的玻碳电极,在近中性的磷酸缓冲溶液中,比较研究对苯二酚在金和银纳米粒子修饰玻碳电极上的电化学响应情况。结果表明金和银纳米粒子均对对苯二酚的电氧化过程具有优越的电催化效果;与银纳米粒子修饰电极相比,金纳米粒子修饰电极表现出了良好的稳定性;对苯二酚在金纳米粒子修饰玻碳电极上的电化学反应是受扩散控制的。     

高效液相色谱法测定高纯度4-甲基邻苯二酚

研究了用高效液相色谱-反相色谱内标法测定由4-甲酚与低浓度过氧化氢水溶液反应生成的高纯度4-甲基邻苯二酚。色谱条件为:C18反相柱,流动相为V(甲醇)∶V(质量分数为0.2%的乙酸水溶液)=50∶50,紫外检测波长为282 nm,流速0.8 mL/min。4-甲基邻苯二酚的最低检测质量浓度为0.04μg/mL,在0.1～100μg/mL范围内4-甲基邻苯二酚的峰面积与质量浓度的线性关系良好(r=0.999 9)。以对苯二酚为内标物,用内标法检测由4-甲酚与低浓度过氧化氢水溶液反应生成的高纯度4-甲基邻苯二酚含量,用此方法4-甲基邻苯二酚回收率为99.9%～100.2%。     

Natural rubber–isotactic polypropylene thermoplastic blends

Thermoplastic elastomers, prepared by melt blending of natural rubber (NR) and isotactic polypropylene (PP) through a dynamic vulcanization technique, were developed during the later 1970s. However, they have certain drawbacks due to thermal degradation and higher molecular weight of NR. In the study reported here, NR was masticated to different levels prior its addition to isotactic polypropylene to improve the flow properties and to reduce the incompatibility resulting from molecular weight mismatch of NR/PP thermoplastic blends. Mixing energy curves of uncrosslinked blends and those of dynamically vulcanized blends crosslinked using different cure systems were compared. The mixing energy curves of blends containing NR of different molecular weight (M _n) and two grades of PP (injection and film grades) were also compared. Technological and processing properties of the dynamically vulcanized (sulphur and peroxide cure systems) and unvulcanized blends were compared with those of the samples containing unmasticated NR. The results indicated that a number average molecular weight in the range 4 × 10⁵ for NR increased the procoessability without significantly affecting the technological properties of NR/PP thermoplastic blends. Among the three cure systems studied Luperox 101 and dicumyl peroxide gave better technological properties than the sulphur‐cured samples. Two antioxidants, viz. quinoline (TDQ) and imidazole (MBI) type, were tried in NR/PP blends. It was found that TDQ imparts better aging resistance compared to MBI. The improvement in processability due to the reduction in molecular weight of natural rubber by mastication is more noticeable in the case of peroxide vulcanized blends compared to sulphur vulcanized samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2063–2068, 2004     

Gel chromatographic investigation of p-benzoquinone and styrene products copolymerized in the presence of BF3·OEt2

The molecular weight distribution of copolymers of p-benzoquinone and styrene was studied by g.p.c.. It was shown that the products synthesized have low molecular weights and narrow MWD. p-Benzoquinone was found to be a copolymer macromolecule regulator.