Determination of hydroquinone and biuret in hydroquinone-containing urea fertilizer

A new colorimetric method for the determination of hydroquinone and a procedure for the analysis of biuret in hydroquinone-containing urea are described. For hydroquinone determination, NH₄Cl (pH = 10) was used as color reagent and the color intensity was measured at 360 nm with a U-VIS-spectrophotometer. The recovery of hydroquinone by this method was found to be 90–110%. Biuret in hydroquinone-urea was assayed by copper-colorimetric method but with the pre-removal of hydroquinone and its oxides with butyl acetate and a chromatography tube. The latter was installed with aluminium oxide and silica-magnesia absorbent respectively. This procedure gave a total of 88.3–93.0% recovery of biuret.     

止血敏合成新工艺的研究

改进了止血敏合成的传统工艺。对苯二酚经硫酸磺化，与二乙胺成盐得止血敏。通过正交试验选出最佳工艺条件，收率为４３％。     

三相催化法合成对-羟基苯甲醚

提出了用三相催化法由对苯二酚和甲醇反应合成对-羟基苯甲醚的工艺路线,产品收率92％,转化率95％。     

As—Mo—V杂多酸盐催化苯酚羟基化制对苯二酚

合成了As-Mo-V杂多酸的十六烷基吡啶盐,元素分析和红外光谱表明,所合成的杂多酸盐具有Keggin结构。以As-Mo-V杂多酸的十六烷基吡啶盐为催化剂,苯酚过氧化氢羟基化选择合成对苯二酚时,反应温度、反应时间、催化剂用量、H2O2用量对催化性能有很大的影响。所确定的最佳反应条件为:反应温度78℃,w(催化剂)/w(苯酚)=0.4%,n(H2O2)/n(苯酚)=0.25,w(乙腈)/w(苯酚)=2,反应时间为2h。此时,苯酚的转化率为17.1%,对苯二酚的选择性为87.3%,邻苯二酚的选择性为6.6%。     

低负载量Ru-W-B/NaY催化剂的制备及其加氢性能

通过浸渍-化学还原法制备出了一系列低负载量的钌基催化剂，在Ru-B二元催化体系中加入少量W，催化剂催化性能显著提高，且采用反加法、超声波辅助法及添加分散剂PEG对载体NaY进行涂覆，进一步改良了Ru催化剂的加氢性能。采用XPS、H2-TPD、XRD、SEM、ICP-OES等一系列表征手段对催化剂物相结构、组成、形貌等进行详细表征，发现采用反加法、添加W、超声波辅助、使用PEG对载体NaY进行涂覆制备的催化剂活性金属粒子分散更均匀，活性位数量更多。以对苯二酚加氢制1，4-环己二醇为探针反应对所制备的催化剂进行活性测试，发现Ru-W-B/NaY-IUP（1500）0.6加氢性能最为优越，对苯二酚转化率为99.7 %，1，4-环己二醇选择性为92.3 %，而钌负载量仅为0.45 %。此外，研究了反应液pH值对加氢反应的影响，发现反应液pH值对反应结果的影响巨大，当反应液呈碱性时，其反应速率得到极大提高，说明碱性环境更有利于对苯二酚加氢制1，4-环己二醇。     

2,5—二羟基—4—正十二烷基苯磺酸钠的合成研究

以对苯二酚为原料经酰化、还原、磺化反应合成了２，５－二羟基－４－正十二烷基苯磺酸钠，并对反应条件进行了研究。     

氢醌单苄醚的合成方法研究

利用水和乙醇作溶剂，利用对苯二酚和氯化苄为原料合成氢醌单苄醚。当对苯二酚氢氧化钠和氯化苄的摩尔比为1．5：1：1。乙醇和水的体积比为2：1时，氢醌单苄醚的收率为56．7％，而且双苄醚的收率最低。     

Highly sensitive and simultaneous determination of hydroquinone and catechol at poly(thionine) modified glassy carbon electrode

A simple and highly sensitive electrochemical method for the simultaneous and quantitative detection of hydroquinone (HQ) and catechol (CT) was developed, based on a poly(thionine)-modified glassy carbon electrode (GCE). The modified electrode showed excellent electrocatalytic activity and reversibility towards the oxidation of both HQ and CT in 0.1 M phosphate buffer solution (PBS, pH 7.0). The peak-to-peak separations (ΔE_p) between oxidation and reduction waves in CV were decreased significantly from 262 and 204 mV at the bare GCE, to 63 and 56 mV, respectively for HQ and CT at the poly(thionine) modified GCE. Furthermore, the redox responses from the mixture of HQ and CT were easily resolved in both CV and DPV due to a difference in the catalytic activity of the modified GCE to each component. The peak potential separation of ca. 0.1 V was large enough for the simultaneous determination of HQ and CT electrochemically. The oxidation peak currents of HQ and CT were linear over the range from 1 to 120 μM in the presence of 100 and 200 μM of HQ and CT, respectively. The modified electrode showed very high sensitivity of 1.8 and 1.2 μA μM⁻¹ cm⁻² for HQ and CT, respectively. The detection limits (S/N = 3) for HQ and CT were 30 and 25 nM, respectively. The developed sensor was successfully examined for real sample analysis with tap water and revealed stable and reliable recovery data.     

Synthesis and Property of Hydroquinone Ether Derivatives

成功地合成了几种新的对苯二酚醚衍生物，并由红外光谱、核磁共振氢谱、碳谱等证实了它们的结构；将其中一种醚化合物和缺电子联吡啶大环化合物自识别、自组装成准轮烷超分子结构，同时对它们的性能进行测定，得到了令人满意的结果，对超分子新材料的研究和应用具有一定的指导意义。     

Toxicity of three phenolic compounds and their mixtures on the gram-positive bacteria Bacillus subtilis in the aquatic environment

Although phenolic compounds are intensively studied for their toxic effects on the environment, the toxicity of catechol, resorcinol and hydroquinone mixtures are still not well understood because most previous bioassays are conducted solely using single compound based on acute tests. In this work, the adverse effect of individual phenolic compounds (catechol, resorcinol and hydroquinone) and the interactive effect of the binary and tertiary mixtures on Bacillus subtilis (B. subtilis) using microcalorimetric method were examined. The toxicity of individual phenolic compounds follows the order catechol > resorcinol > hydroquinone with their respective half inhibitory concentration as 437, 728 and 934 µg mL⁻¹. The power-time curve of B. subtilis growth obtained by microcalorimetry is in complete agreement with the change in turbidity of B. subtilis against time, demonstrating that microcalorimetric method agrees well with the routine microbiological method. The toxicity data obtained from phenolic compound mixtures show that catechol and hydroquinone mixture possess synergistic effect while the other mixtures display additive joint actions. Furthermore, the concentration addition (CA) and independent action (IA) models were employed to predict the toxicities of the phenolic compounds. The experimental results of microcalorimetry show no significant difference on the toxicity of the phenolic compound mixtures from that predicted by CA. However, IA prediction underestimated the mixture effects in all the experiments.