香兰素合成研究

研究了利用电解草酸饱和溶液制得的乙醛酸溶液为原料,与愈创木酚缩合,缩合产物电解氧化,酸化脱羧制取香兰素的工艺过程,并优化了反应工艺条件.     

5-硝基愈长木酚的合成

5-硝基愈创木酚作为高效、低毒植物调节剂,一直倍受关注.它的合成目前主要采用愈创木酚硝化法,以发烟硝酸和冰醋酸混酸做硝化剂.本文由愈创木酚为起始原料,经酚酯化、硝化、水解等步骤合成了5-硝基愈刨木酚.酚酯化采用碱催化法,收率可达96%以上;硝化反应则采用乙酸酐和硝酸混合物为硝化剂.5-硝基愈创木酚最高收率可达到91%.     

Anaerobic toxicity and biodegradability of pulp mill waste constituents

Batch bioassays have been conducted to characterize the response of methanogenic bacteria to several constituents of sulfite evaporator condensate. The results can be grouped into three ranges with increasingly severe consequences to anaerobic reactors: a low concentration, no effect range; a medium concentration range where methanogenesis is temporarily interrupted or slowed down, but may return to normal; and a high concentration range where methanogenesis is permanently inhibited. In some cases the toxicant was metabolized when present in the lower concentration ranges. There was also evidence that mechanisms other than fermentation to methane were significant in accounting for removal of the toxicants from solution. Organisms acclimated to low concentrations of a toxicant are better able to withstand a shock load of that toxicant than are unacclimated organisms.     

重氮盐水解制备愈创木酚的实验工艺研究

概述了邻甲氧基苯重氮盐水解制备愈创木酚的机理,指出了反应所需的基本条件。通过单一因素实验研究,考察了水解温度、重氮盐稀释倍数和滴加时间、水酸质量配比、催化剂用量等对水解产品收率的影响,弥补了对重氮盐水解制备愈创木酚工艺进行详细研究的空白。结果表明,水解温度和催化剂用量对产品收率影响显著,重氮盐的稀释倍数、滴加速度和水解液中水酸配比有最佳值。     

重氮盐水解制备愈创木酚的实验工艺研究

概述了邻甲氧基苯重氮盐水解制备愈创木酚的机理,指出了反应所需的基本条件。通过单一因素实验研究,考察了水解温度、重氮盐稀释倍数和滴加时间、水酸质量配比、催化剂用量等对水解产品收率的影响,弥补了对重氮盐水解制备愈创木酚工艺进行详细研究的空白。结果表明,水解温度和催化剂用量对产品收率影响显著,重氮盐的稀释倍数、滴加速度和水解液中水酸配比有最佳值。     

乙醛酸制备香兰素工艺条件的优化

采用乙醛酸工艺研究了甲基香兰素的合成方法，讨论了3-甲氧基-4-羟基苯乙醇酸、3-甲氧基-4-羟基扁桃酸制备中温度、物料比、催化剂、压力对产率的影响，通过选择合适的反应条件，可以提高香兰素的得率。     

TiO2悬浮体系下光催化降解愈创木酚的动力学研究

以木素的模型物愈创木酚(G-M)为对象,采用自制的纳米TiO_2作光催化剂,对G-M光催化降解的动力学特性进行了研究。根据吸附特性和表面光催化降解反应得到了G-M光催化降解过程的动力学方程:1/r=1.744/C 0.1034。由半衰期法对动力学方程的讨论,发现实测值与计算值的差是由于中间产物在催化剂表面上与G-M的竞争,降低了催化剂对G-M有效降解的程度。对于不同初始浓度,其动力学方程近似表达成3种不同的形式。     

Effect of smoke application to field‐grown Merlot grapevines at key phenological growth stages on wine sensory and chemical properties

Background and Aims: Smoke exposure of grapevines and development of smoke taint in wine are issues of increasing incidence and severity. There is limited understanding of the effect of phenological stage at the time of smoke exposure on taint development. The aim of this study was to demonstrate the variation in smoke uptake and taint development between and within seasons. Methods and Results: Smoke was applied to field‐grown Merlot grapevines at 12 stages of vine development over three growing seasons. Key periods of vine sensitivity to smoke taint in wine were (i) from shoots at 10 cm to full bloom (low levels of smoke taint); (ii) from berries at pea size to the onset of veraison (variable levels of smoke taint); and (iii) between 7 days post‐veraison and harvest (high levels of smoke taint). Conclusions: The severity of taint in wine varied depending on the phenological timing of grapevine smoke exposure. Taint was elevated when exposure occurred between 7 days post‐veraison and harvest. The carry‐over of smoke constituents the following season was not detectable in wine but yields were reduced. Significance of the Study: This is the first study to demonstrate the timing of smoke exposure to critically affect wine chemical and sensory characters. These effects were consistent and reproducible over three seasons.     

The Use of Lewis Acids During Rapid Steam Hydrolysis

Mixed hardwood chips were treated with various concentrations of aluminum chloride hexahydrate, aluminum sulfate hydrate, and ferric chloride and were subjected to rapid steam hydrolysis pretreatment (RASH). The three levels included 0.01, 0.03, and 0.05 moles of catalyst per 1000 grams of wood. Rapid steam hydrolysis (RASH) was done from 180° to 260°C at 20°C intervals for one minute. The Lewis acid catalyst affected the overall recovery yield of solids, the recovery values of the individual components, the enzymatic rates, and the methanol and water solubility. Overall recovery of pretreated solids generally decreased with the increase in levels of the catalyst. The one exception was AlCl₃ ·6H₂O where the minimum recovery levels were reached at 0.03 moles per 1000 grams of wood and increased at the higher level of catalyst. Cellulose degradation occurred in the temperature range of 250° to 260°C for the control and at the two lower concentrations of the catalyst. At the higher levels of catalyst, appreciable amounts of cellulose degradation occurred at lower temperatures. Hemicellulose solubilization and degradation were extremely sensitive to the RASH temperature and to the levels of catalyst. Almost all hemicellulose was lost at high temperatures or at high levels of catalyst. Losses of lignin appeared to be affected mainly by the RASH temperature and not by the changes in the levels of catalyst.

In contrast, both the temperature and the level of catalyst strongly affected the rates of enzymatic hydrolysis. Generally, the intermediate level of catalyst seemed to give the highest rates of enzymatic hydrolysis at the lowest temperature. Methanol and water solubles increased in the presence of the catalyst and reached a maximum at levels of 0.03 moles between 230° to 250°C.