辣根过氧化物酶降解苯酚废水催化特性研究

采用辣根过氧化物酶催化降解苯酚,研究了辣根过氧化物酶浓度、pH值、反应温度对苯酚去除率的影响。结果表明,辣根过氧化物酶生物催化体系对苯酚有良好的降解效果。当温度为30℃,pH值为6时,在苯酚、H2O2、辣根过氧化物酶浓度分别为1 mmol/L,1.2 mmol/L,0.5μg/mL条件下,反应25 min,可以获得70%左右的苯酚去除率。利用双倒数作图法测定了不同酶浓度的催化动力学参数,动力学参数Kcat,Kcat/Km表明,苯酚的去除率和催化反应速率随着酶浓度的增加而增大;辣根过氧化物酶的催化效率与催化体系中酶和底物浓度有关,过高的底物浓度会降低酶的催化效率。     

辣根过氧化物酶处理邻苯二酚废水的研究

研究了用辣根过氧化物酶催化处理邻苯二酚废水的效果.结果表明,用辣根过氧化物酶可以有效地去除邻苯二酚.其最佳处理条件为:pH值4.4、过氧化氢与邻苯二酚的摩尔比约2∶1、反应时间30 min,适当增加酶用量可以明显缩短反应时间.     

辣根过氧化物酶催化去除水中染料的特性研究

首次采用辣根过氧化物酶催化降解直接黑38和偶氮荧光桃红染料,发现p H、反应温度、H2O2浓度对酶促反应有重要影响。辣根过氧化物酶可以在p H为3.0~9.0、温度25~65℃范围内有效去除直接黑38和偶氮荧光桃红。动力学实验结果表明,辣根过氧化物酶催化反应动力学符合一级反应动力学,并利用双倒数作图法测定了酶催化直接黑38动力学参数Km。     

辣根过氧化物酶催化合成水溶性导电聚苯胺的研究

以辣根过氧化物酶(HRP)为催化剂、十二烷基硫酸钠(SDS)为模板研究了生物催化水溶性导电聚苯胺(PANI)的合成.探讨了反应体系的pH值、过氧化氢浓度和SDS浓度对聚合反应的影响,并研究了HRP催化苯胺聚合过程中性质的变化.紫外可见扫描光谱分析和电导率测定的结果表明,在以SDS为模板的条件下,HRP催化水溶性导电聚苯...     

HRP催化淀粉与酚类接枝聚合物的合成研究

以辣根过氧化物酶(HRP)/H2O2为催化体系,催化降解淀粉和3,5-二羟基苯甲酸(3,5-DBA)进行自由基接枝共聚反应,合成了淀粉和酚类接枝共聚物。探讨了温度和pH对酶活力的影响以及接枝条件对接枝共聚反应的影响。通过FTIR、1HNMR和GPC对接枝改性淀粉的化学结构进行了表征。产物用作皮革鞣剂时,显示了良好的应用性能。     

辣根过氧化物酶催化降解苯酚过程的研究

研究了用辣根过氧化物酶催化处理苯酚废水的效果,结果表明,用辣根过氧化物酶可以有效地去除苯酚。其最佳处理条件为溶液的H_2O_2浓度2.5 mmol·L-1、pH值4.5、温度30℃、苯酚初始浓度1.0 mmol·L~(-1)、反应时间15 min、酶用量1.0μg,降解率达到86.5%。适当增加酶用量可以明显缩短反应时间。     

酶催化水溶性导电聚苯胺的模板导向合成与表征

对辣根过氧化物酶(HRP)催化水溶性导电聚苯胺的合成进行了研究.以聚乙烯磺酸钠(PVS)作为反应的聚阴离子模板.详细地研究了反应体系的pH值、H2O2浓度及苯胺与PVS的摩尔比对苯胺聚合的影响.用UV-vis-near-IR、FTIR及四探针电导率测试仪对产物进行了表征,并与其他模板聚合产物进行了比较.研究结果表明,PVS可作为HRP催化苯胺聚合的模板,合成的PVS/PANI的电导率为4.78×10-1S·cm-1,反应体系的pH值应控制在4.0～5.0,H2O2浓度以20 mmol·L-1为宜,PVS与苯胺的摩尔比应控制在1～1.5.     

辣根过氧化物酶生物降解五氯酚

采用辣根过氧化物酶催化降解五氯酚(PCP),探讨了pH值、温度、n(H2O2):n(PCP)和酶用量等因素对五氯酚去除率的影响.通过向反应体系中投加非离子型表面活性剂Tween-40,增强了辣根过氧化物酶的稳定性,延长了酶活性时间,并对其作用机理进行了探讨.实验表明非离子型表面活性剂Tween-40能够提高五氯酚的去除率,降低处理成本.     

一种基于纳米胶团自组装结构人工过氧化物酶

用十二烷基硫酸钠与血红素和组氨酸通过自组装的方式构建了一种纳米结构人工过氧化物酶(AP)。利用紫外可见光分光光度仪测量AP结构酶促反应过程,观察到了过氧化物酶活性在pH 8.0,50 mmol/L Na2HPO4-NaH2PO4缓冲溶液时达到最大。该AP的米氏常数Km、催化速率以及催化效率分别为5.5μmol/L、0.6 s-1、0.011μM-1.s-1,其催化效率为天然辣根过氧化物酶的15%。     

共固定化葡萄糖氧化酶研究进展

葡萄糖氧化酶广泛应用于分析检测、生物传感、食品工业等领域.酶的共固定化可以在同一反应体系中因偶联反应而提高催化效果.本文综述了近年来葡萄糖氧化酶与氯过氧化物酶、辣根过氧化物酶、脂肪酶等其他酶共固定化研究进展,展望了葡萄糖氧化酶共固化载体的设计及其应用.     

亚硝酸钠/盐酸催化氧气氧化碘化芳烃、醚、酚化合物

以廉价易得的盐酸/亚硝酸钠为催化剂,碘为碘化试剂,通过分子氧,氧化碘化芳烃、醚、酚的活泼芳香底物,发展了温和条件下高效碘化方法。以苯甲醚为模型底物,系统考察了影响反应的因素,确定的最佳反应条件为:20℃氧气条件下,1,2-二氯乙烷(DCE)为溶剂,n(苯甲醚)∶n(碘)∶n(亚硝酸钠)∶n(HC l)=1∶0.515∶0.05∶0.1。该方法碘原子经济性好,催化剂廉价易得,反应时间大为缩短,选择性好、转化率高,副产物仅为水,容易处理,绿色环保、易于工业化;通过反应机理验证实验,提出了可能的催化循环机理。     

Toxicity of soluble products from the peroxidase‐catalysed polymerization of substituted phenolic compounds

The residual toxicities of aqueous solutions of phenol and substituted phenols were investigated following polymerization under the catalytic action of soybean peroxidase (SBP) and horseradish peroxidase (HRP) enzymes. The treated mixtures obtained from the enzymatic polymerization of these phenols were usually significantly more toxic than expected, and in several cases, the residual toxicity exceeded the initial toxicity of the solution of untreated parent compound. However, this residual toxicity tended to be lower when combinations of these phenols were co‐polymerized. The decrease in toxicity was attributed to the different polymeric products which form as a result of a cross‐coupling between products of the enzyme‐catalysed oxidation of parent phenols. The residual toxicities obtained using either SBP or HRP were not significantly different in most cases. © 2000 Society of Chemical Industry     

Facile enzymatic preparation of fluorescent conjugated polymers of phenols and their application in sensing

The recognized drawback of utilizing metal catalysts for the synthesis of fluorescent conjugated polymers (CP) is the requirement for extensive purification to ensure complete removal of residual catalyst that would otherwise quench the fluorescence. In addition, typical synthesis of fluorescent CP involves multiple steps, monomers and solvents with varying levels of toxicity. This work demonstrates the possibility of utilizing oxidoreductase enzymes as the catalyst, for the one step polymerization of naturally occurring phenols to yield fluorescent conjugated polyphenols. The metal in the active site of the enzyme remains chelated during the synthesis allowing the polymers to be fluorescent as synthesized without the need for extensive purification. Three natural phenols, 4‐hydroxyphenylacetic acid, hydroxytyrosol, and chlorogenic acid were polymerized using Horseradish peroxidase as the biocatalyst. Spectroscopic techniques, UV–vis, Fourier transform infrared Spectroscopy–Attenuated Total Reflectance, and fluorescence, are used to characterize chemical structure and photoluminescence of these polymers. The polyphenols exhibit fluorescence with significant stokes shift in the range 30–100 nm rendering them useful in fluorescence quenching‐based sensors. Preliminary studies on use of these polymers, in the detection of nitro‐aromatic compounds in solution through using fluorescence‐quenching are also presented. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46496.     

改性膨润土在有机反应中的应用

讨论了膨润土改性的不同途径，论述了改性膨润土在有机反应中的使用特点和催化效果，从而证明改性膨润土作为催化剂或催化剂载体在有机反应中具有广阔的应用前景。     

Highly efficient heterogenous catalyst for O-arylation of phenols with aryl halides using natural ferrous chamosite

Natural ferrous chamosite-catalyzed arylation of phenols with aryl iodides and bromides afforded the corresponding ethers in moderate to excellent yields. This ligand-free, natural catalyst catalyzed coupling of aryl iodides and aryl bromides with phenols resulted in high yields of diaryl ether formation in the absence of any additive. The catalyst was quantitatively recovered from the reaction by a simple filtration and reused for a number of cycles.     

Unmodified Nano‐Powder Magnetite Catalyzes a Four‐ Component Aza‐Sakurai Reaction

A new catalyst for an old material: magnetite is an excellent Lewis acid catalyst for the four‐component aza‐Sakurai reaction. The process could be repeated up to 15‐times without losing effectiveness, with the catalyst recycling being as easy as the use of a simple magnet. The catalyst is selective and could discriminate between aldehyde and ketone functionalities, catalyzing first the reaction with the higher electrophilic aldehyde.     

Modified microperoxidases exhibit different reactivity towards phenolic substrates

The reactivity of several microperoxidase derivatives with different distal-site environments has been studied. The distal-site environments of these heme peptides include a positively charged one, an uncharged environment, two bulky and doubly or triply positively charged ones, and one containing aromatic apolar residues. The reactivity in the catalytic oxidation of two representative phenols, carrying opposite charges, by hydrogen peroxide has been investigated. This allows the determination of the binding constants and of the electron-transfer rate from the phenol to the catalyst in the substrate/microperoxidase complex. The electron-transfer rates scarcely depend on the redox and charge properties of the phenol, but depend strongly on the microperoxidase. Information on the disposition of the substrate in the adducts with the microperoxidases has been obtained through determination of the paramagnetic contribution to the 1H NMR relaxation rates of the protons of the bound substrates. The data show that the electron-transfer rate drops when the substrate binds too far away from the iron and that the phenols bind to microperoxidases at similar distances to those observed with peroxidases. While the reaction rate of microperoxidases with peroxide is significantly smaller than that of the enzymes, the efficiency in the one-electron oxidation of phenolic substrates is almost comparable. Interestingly, the oxyferryl form of the triply positively charged microperoxidases shows a reactivity larger than that exhibited by horseradish peroxidase.     

Catalytic pyrolysis of waste rice husk over mesoporous materials

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH₃ temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.     

硅胶负载硫酸催化酯化反应研究

用热浓硫酸处理硅胶,制备了硅胶负载硫酸催化剂,用冰乙酸与异戊醇的酯化反应考察了催化剂的催化效果。结果表明,该催化剂经多次使用,仍具有良好的催化性能。当催化剂用量为2g,酸与醇的摩尔比为2.61时,4次合成乙酸异戊酯产率平均达到70.6%,与相同条件下浓硫酸催化效果相当。     

清洁氧化法合成己二酸

以30%的双氧水为氧源, 钨酸钠为催化剂,KF-101为助催化剂,催化氧化环己烯清洁合成己二酸,考察了助催化剂、催化剂用量、反应物物质的量比、反应时间等对反应的影响,通过正交实验确定优化条件,在优化条件下,己二酸收率达93%.