Evaluation of the extent of the oxidation reaction during chlorine bleaching of pulp

A modified method was developed to evaluate how much chlorine is consumed by the oxidation reaction during the chlorine bleaching process. This evaluation is, in principle, based on the sum of chloride produced during the chlorination stage (C-stage) and produced during alkali treatment of both the C-stage effluent and the chlorinated pulp. Results obtained by this method proved that about 50%–75% of chlorine was consumed by the oxidation reaction during chlorine bleaching, depending on the reaction condition of chlorination. Even under a reaction condition that is not favorable to an oxidation reaction (low pH), approximately three electrons were abstracted from one lignin structural unit by chlorine bleaching. This result provides additional evidence for our recent observation that lignin is extensively oxidized during chlorine bleaching even when pure chlorine without any chlorine dioxide substitution was used.Part of this paper was presented at the 40th Lignin Symposium. Tsukuba, Japan, October 12, 1995     

绿玉树春季乳汁的碳氢化合物及甾醇的GC-MS分析

取西双版纳的成年绿玉树和重庆引种的2年生海南绿玉树乳汁,自然干燥后用CS2溶解,经气相色谱-质谱联用机(GC-MS)分析,西双版纳绿玉树乳汁共检出52个峰,鉴定出33个峰,23种成分.除绿玉树的"指纹"成分绿玉树甾醇以外,还含有9～36个碳原子的多种烷烃,如2,6-二甲基壬烷、3,7-二甲基癸烷、十二烷、二十烷、正二十烷、二十一烷、二十三烷、二十五烷、二十七烷、三十烷、三十六烷、石竹烯以及1,2-苯二羧酸、酯类和单质硫(S8)等,其中烷烃和烯烃的总相对含量为14.57%;海南幼年绿玉树乳汁有42个峰,鉴定出33个峰,21种成分.除绿玉树甾醇外,主要也含9～26个碳原子的烷烃,如壬烷、十六烷、十七烷、十八烷、二十烷、正二十烷、二十一烷、二十二烷、β-芘澄茄烯、异石竹烯、大根香叶烯-D以及1,2-苯二羧酸、酯类和单质硫(S8)等,其成分与西双版纳绿玉树十分接近,但绿玉树的"指纹"成分绿玉树甾醇的含量(17.40%)要稍高于西双版纳成年绿玉树(10.91%),而烷烃和烯烃的相对含量(5.01%)要低于西双版纳成年绿玉树(14.57%).     

Determination of ligustilide in the brains of freely moving rats using microdialysis coupled with ultra performance liquid chromatography/mass spectrometry

In this paper, microdialysis combined with ultra performance liquid chromatography/mass spectrometry (UPLC-MS) was applied for the determination of ligustilide in freely moving rats' brain. The extracellular unbound ligustilide could be detected in rat brain within the first time interval (0-20 min) after nasal administration but not after oral administration. This result showed that ligustilide could quickly enter the brain after nasal administration; which implied that ligustilide may have a rapid onset of action. This work demonstrated the potential application of microdialysis combined with UPLC-MS in pharmacokinetic studies. Furthermore, the advantage that fewer animals used in the microdialysis experiment was confirmed.     

Ethyl p-methoxycinnamate isolated from a traditional anti-tuberculosis medicinal herb inhibits drug resistant strains of Mycobacterium tuberculosis in vitro

Many plants are used in Ayurveda for the treatment of tuberculosis. Our aim was to examine if these plants possess any specific molecule that inhibits Mycobacterium tuberculosis. One of them, Kaempferia galanga, yielded an anti-TB molecule, ethyl p-methoxycinnamate (EPMC). By resazurin microtitre assay (REMA), EPMC was shown to inhibit M. tuberculosis H37Ra, H37Rv, drug susceptible and multidrug resistant (MDR) clinical isolates (MIC 0.242-0.485 mM). No cross resistance was observed to any standard anti-TB drugs in the MDR strains. The compound did not inhibit any prototype bacteria tested. EPMC seems to be a potential anti-TB lead molecule.     

Iron-binding compounds produced by white-rot fungusPhanerochaete sordida YK-624

Iron-binding compounds were isolated from a culture ofPhanerochaete sordida YK-624 and were found to bind to Fe(III) preferentially compared with Fe(II). Two iron-binding compounds were purified to near-homogeneity with gel permeation chromatography. Hydrolysis of the iron-binding compounds with 6N hydrochloric acid gave ninhydrin-negative products. The molecular weight of these compounds was 3–5 kDa. These compounds may play an important role in the reduction of extracellular manganese dioxide to Mn(II) by intracellular ferrireductases for lignin degradation by manganese peroxidase.     

RTO技术治理挥发性有机废气工程应用研究

指出了蓄热式氧化焚烧技术是目前治理挥发性有机废气较为有效的一项措施。以医药化工有机废气为研究对象,采用气相色谱法分析了特征污染物废气种类及进气浓度,研究了RTO氧化焚烧技术治理有机废气实际运行效果,结果表明:RTO对甲醇削减率达94.8%,四氢呋喃削减率达94.6%,二氯甲烷削减率达95.3%,甲苯和乙醚削减率分别达88.0%和96.8%,且排放浓度满足《大气污染物综合排放标准》(GB16297-2012)。最后结合医药化工行业RTO运行所存实际问题及对应解决方案进行了归纳总结,并对该技术的发展提出了展望。     

气相色谱法检测废气中VOCs的不确定度评定

以废气中挥发性有机物（VOCs）的检测不确定度为例,分析了不确定度分量的来源及评定,给出了废气中VOCs检测的扩展相对标准不确定度。     

基于量子化学的木质素热裂解中环类化合物形成的理论及实验研究

利用傅里叶变换红外光谱仪分析木质素微观结构,应用裂解气相色谱-质谱联用技术(Py-GC/MS)进行木质素的热裂解产物分析。研究结果表明:300和400℃时没有检测到多环芳烃等复杂结构,可见在该温度下,裂解产物并未发生二次缩合作用;在800℃下,苯和甲苯的GC含量增加,苯酚基本保持不变,并开始出现多环芳烃化合物。以密度泛函理论B3LYP/6-31G(d,p)为基础对木质素的裂解反应过程进行了分子动力学模拟研究,对比分析实验数据和模拟数据,推断出木质素热裂解中环类化合物的形成演化机理:300~400℃主要发生CC键的断裂和羟基脱落(路径R5-1)以及C1—Cα键的断裂(路径R5-2);400~800℃发生的C1—Cα键断裂反应(路径R4-1),苯环上甲氧基官能团脱去反应(路径R4-4)和苯环上甲氧基均裂(路径R5-3);与苯环上甲氧基官能团均裂反应(路径R4-3)相比,苯环C1—Cα断裂反应(路径R4-2)发生的可能性更大;路径2、路径3和路径5的产物量均在800℃左右达到最大,其产物分别为联苯、菲以及芘。     

高效液相色谱法测定防腐木材中戊唑醇含量的不确定度评估

利用高效液相色谱法测定了防腐木材中的戊唑醇含量。分析了测定过程中由样品称取质量、样品前处理定容体积、标准溶液质量浓度、液相色谱仪定量重复性、平行试验重复性产生的不确定度的计算方法,确定了防腐木材样品中戊唑醇含量不确定度的最终合成与表示为（494±64）μg／g（k ＝2）。     

榆木蠹蛾性诱剂的合成及林间诱蛾试验

利用毛细管气相色谱分析榆木蠹蛾处女雌蛾性腺体提取物、化学合成相应的标准化合物并通过触角电位分析及林间诱蛾试验,旨在找到一种对榆木蠹蛾成虫具有强引诱活性的性诱剂.结果表明:提取物中存在反-3-十四碳烯醇(E3 - 14∶OH)、顺-3-十四碳烯醇(Z3 - 14∶ OH)、反-3 -十四碳烯醇乙酸酯(E3 - 14∶Ac)、顺-7-十四碳烯醇乙酸酯(Z7-14∶ Ac)和顺-3-反-5-十四碳烯醇乙酸酯(Z3E5 -14∶ Ac).榆木蠹蛾雄蛾对Z7-14∶ Ac产生最强的触角电位(EAG)反应,为4.95 mV,极显著高于其他化合物,其他依次是E3 - 14∶Ac、Z3E5 -14∶Ac、E3E5 -14∶ Ac、Z3 - 14∶Ac、腺体提取物、E7 - 14∶Ac,其中乙酸酯化合物EAG值极显著高于其相应的醇(P＜0.01).林间诱蛾活性试验表明:Z7- 14∶ Ac有诱蛾活性,E3 - 14∶Ac和Z3E5 - 14∶ Ac有显著的增效作用,Z7-14∶ Ac、E3 - 14∶Ac和Z3E5 - 14∶ Ac按10∶ 4∶4的比例配成每个含900 μg性诱剂的诱芯具有很好的诱蛾活性,单诱芯日平均诱蛾数达11.02头.