新型两性捕收剂的研究

采用新型两型捕收剂浮选磷灰石和方解石的结果表明,β-胺基烷基磷酸在弱酸性范围对磷灰石有较强的捕收能力:在碱性范围对方解石有较强的捕收能力。挖制浮选pH值,有可能实现二者分离。β-胺基烷基亚磷酸脂对磷灰石,方解石的捕收能力均较弱.电位测定表明,两性捕收剂在酸性范围使磷灰石表面电位向正值增加,在碱性范围便磷灰石,方解石表面负电位增加。β-胺基烷基膦酸在碳灰石表面作用的有效组分为RNHC_2H_4PO_3H~-,在方解石表面作用的有效组分为RNHHC_2H_4PO_3~(2-)。红外光谱证明,β-胺基烷基膦酸在碳灰石及方解右表面均能发生化学吸附。     

金属离子对磷矿醚胺反浮选脱硅的影响

本文采用醚胺类捕收剂D-609作为磷矿反浮选脱硅捕收剂,通过纯矿物试验和矿物表面Zeta电位分析,探索了Ca~(2+)、Mg~(2+)、Fe~(3+)、Al ~(3+)对石英和磷灰石浮选的影响。试验结果表明:Al ~(3+)、Fe~(3+)可以明显抑制石英的上浮;Ca~(2+)在酸性条件下对石英有较弱的抑制作用,在碱性条件下可以活化石英;Mg~(2+)在酸性和碱性条件下可以抑制石英的浮选;Ca~(2+)、Mg~(2+)、Fe~(3+)、Al ~(3+)对磷灰石浮选的影响较小。     

磷选矿回水处理的优化探讨

在磷矿选矿过程中,选矿废水中除含有大量金属离子外,还含有较多的有机物,对选矿废水进行处理并达标排放,不仅难度大,而且成本高,所以回用处理后的选矿废水很有必要。对废水中常见的Mg~(2+)、SO_4~(2-)、PO_4~(3-)、Ca~(2+)等离子对磷矿浮选作业的影响进行了试验研究,结果表明:Ca~(2+)、Mg~(2+)对磷矿正浮选和反浮选影响较大,SO_4~(2-)、PO_4~(3-)对浮选影响较小。采用双碱法处理选矿废水后,可用于浮选作业,在反浮选过程中可有条件地直接回用废水,实现了废水循环利用,达到了"零排放"目标。     

反式-4-氨基-环己基醋酸乙酯盐酸盐的制备过程

正专利披露了反式-4-氨基-环己基醋酸乙酯盐酸盐的制备过程:a)4-硝基苯醋酸在质子溶剂中加氢反应,反应条件是温度40~50℃,催化剂钯/碳(钯载于碳上),过压0.1~0.6巴;b)步骤a)得到的产物4-氨基苯醋酸进一步加氢反应,反应条件是温度50~60℃,过压1~4巴;c)加热步骤b)得到的4-氨基-环己基醋酸,在盐酸乙醇中回流1~3小时,并且如果需要在除去溶     

云南某碳酸盐型胶磷矿双反浮选脱硅工艺流程探讨

在云磷集团450万t/a浮选厂昆阳150万t/a系列单一反浮选工艺流程基础上,为进一步降低浮选磷精矿中SiO_2的含量,对3种不同的双反浮选脱硅(先脱镁再脱硅、先脱硅再脱镁、脱镁-分级-脱硅)工艺流程进行了对比试验,结果表明,脱镁-分级-脱硅工艺流程脱硅效果好,药剂消耗低,精矿指标(精矿P_2O_5品位为30%、MgO品位为0.71%、SiO_2品位为13.71%、P_2O_5回收率为82.13%)达到了预期要求,且脱硅浮选泡沫较脆,易于调控,因此推荐采用该流程。     

溴化铁催化下(E)-3-苯乙烯基异香豆素的合成

以CH_2ClCH_2Cl作溶剂,(E)-1,4-二芳基烯炔在FeBr3催化下,可以顺利发生分子内环化反应,得到(E)-3-苯乙烯基异香豆素(2a～2c),产率42%～60%,其产物结构经~1H NMR、~(13)C NMR和GC-MS表征。     

反式-4-氨基-环己基醋酸乙酯盐酸盐的制备过程

正发明摘要专利披露了反式-4-氨基-环己基醋酸乙酯盐酸盐的制备过程:a)4-硝基苯醋酸在质子溶剂中加氢反应,反应条件是温度40~50℃,催化剂钯/碳(钯载于碳上),过压0.1~0.6巴;b)步骤a)得到的产物4-氨基苯醋酸进一步加氢反应,反应条件是温度50~60℃,过压1~4巴;c)加热步骤b)得到的4-氨基-环己基醋酸,在盐酸乙醇中回流1~3小时,并且如果需要在除去溶剂后,将乙腈加入得到的残留物中,然后蒸馏掉。     

2-溴-4-甲氧基-5-[3-(吡咯烷-1-基)丙氧基]苯胺的合成

以4-溴-2-甲氧基苯酚(2a)、1-氯-3-碘丙烷(3)和吡咯烷为原料,通过一锅法反应,合成得到1-[3-(4-溴-2-甲氧基苯氧基)丙基]吡咯烷(4a),再经过硝化、还原两步反应,得到目标化合物2-溴-4-甲氧基-5-[3-(吡咯烷-1-基)丙氧基]苯胺(1)。产物以及中间体结构经~1H NMR和ESI-MS表征。对于每一步反应过程进行了讨论,并以化合物4a的合成为模型反应,重点讨论影响产物收率的因素,确定其最佳反应条件为:反应溶剂为乙腈,n(2a)∶n(3)∶n(吡咯烷)=1.0∶1.2∶2.4,n(K_2CO_3)∶n(2a)=4∶1,n(KI)∶n(2a)=1.5∶1.0,反应温度85℃。该反应条件也被用于1-[3-(2-甲氧基-5-硝基苯氧基)丙基]吡咯烷(4b)的合成。     

2-溴-1,1,1-三氟-2-甲基丙烷的合成工艺研究

首次以1,1,1-三氟-2-甲基-2-丙醇(2)为原料,先与磺酰氯(3)反应生成磺酰酯(4),再经置换溴化得到2-溴-1,1,1-三氟-2-甲基丙烷(1)。产物结构经~1H NMR及~(19)F NMR表征;通过试验发现:选择甲基磺酰氯(3a)与2反应生成甲基磺酰酯(4a),再溴化得1,收率较高;通过对4a合成工艺优化,确定最佳反应条件为:选择三乙胺/DMAP体系,滴加3a的投料方式,n(2):n(3a)为1.00:1.05,30℃反应12 h,收率99.7%;通过对1合成工艺优化,确定最佳反应条件为:LiBr/n-Bu_4NBr/丙酮为置换溴化体系,n(LiBr):n(4a)为1.5:1.0,n(n-Bu_4NBr):n(4a)为1:10,58℃回流反应14 h,收率89.6%。该方法具有操作方便、质量可控、设备要求不高、对环境友好等优点,适合规模化生产。     

藏红T萃取-浮选光度法测定痕量钯

研究了Pd(Ⅱ)-Br~--藏红T(ST)萃取-浮选体系的最佳条件。在pH 1.5～0.2M盐酸介质中,Pd(Ⅱ)-Br~--ST离子缔合物可被苯定量浮选。浮选物溶于丙酮,在520 nm进行光度测定,ε_(520mm)=2.2×10~5l·mol~(-1).cm~(-1)。测得Pd:Br:ST=1:5:3,推测生成了[PdBr_4~(2-)·2 ST~+]·EBr~-·ST~+]复杂离子缔合物。选择性也较好,可用于矿石和有色冶炼渣中痕量钯的测定。提出了生成复杂离子缔合物是缔合物能萃取浮选的主要原因,也是萃取-浮选光度法灵敏度普遍高于相应萃取光度法的根本原因。     

卤系阻燃剂阻燃机理的探讨及应用

本文阐述了塑料燃烧的理论和卤系阻燃剂的阻燃机理，并推断卤系阻燃剂与聚合物的热降解数据曲线可应用在指导阻燃材料的配方设计上。同时指出卤系阻燃剂依然有较好的发展前景。     

Disaccharide mimetics of the aminoglycoside antibiotic neamine

A highly convergent approach has been employed for the facile synthesis of a library of 24 disaccharides that are alpha(1-3), beta(1-3), alpha(1-4), or beta(1-4) linked and contain 2-4 amino groups. Fourier-transformation ion cyclotron resonance mass spectrometry (FT-ICR MS) has been used to determine dissociation constant (Kd) values for the binding of the disaccharides to a prototypical fragment of 16S ribosomal RNA. Several derivatives bound with affinities similar to that of neamine. Structure-activity relationships have revealed the substitution pattern that is important for high-affinity binding. The compounds described here are unique lead compounds for the design of novel aminoglycoside antibiotics.     

Measurement of enzymatic activity and specificity of human and avian influenza neuraminidases from whole virus by glycoarray and MALDI-TOF mass spectrometry

Influenza neuraminidases hydrolyze the ketosidic linkage between N-acetylneuraminic acid and its adjacent galactose residue in sialosides. This enzyme is a tetrameric protein that plays a critical role in the release of progeny virions. Several methods have been described for the determination of neuraminidase activity, usually based on colorimetric, fluorescent, or chemiluminescent detection. However, only a few of these tests allow discrimination of the sialyl-linkage specificity (i.e., α2-3- versus α2-6-linked sialyllactosides) of the neuraminidase. Herein we report a glycoarray-based assay and a MALDI-TOF study for assessing the activity and specificity of two influenza neuraminidases on whole viruses. The human A(H3N2) and avian A(H5N2) neuraminidase activities were investigated. The results from both approaches demonstrated that α2-3 sialyllactoside was a better substrate than α2-6 sialyllactoside for both viruses and that H5N2 virus had a lower hydrolytic activity than H3N2.     

Identification of sex pheromone components of redbacked cutworm,Euxoa ochrogaster,and modification of sex attractant blend for adult males

Pheromone washes from calling female moths of redbacked cutworm,Euxoa ochrogaster (Guenée), contained the following acetates that are structurally similar to those of known lepidopteran pheromones (%): decanyl (8.7), dodecanyl (8.5), (E)-5-dodecenyl (3.3), (Z)-5-dodecenyl (76.4), (Z)-7-dodecenyl (3.1), and (Z)-9-dodecenyl (trace<0.5%). This is the first time that (Z)-5-dodecenyl acetate has been identified as a pheromone component. Three types of specific receptor cells were found in the male antennae, and they responded to (Z)-5-decenyl acetate, (Z)-5- and (Z)-7-dodecenyl acetates, respectively. Strong electroantennographic detector responses were also recorded for these three acetates and for (Z)-5-undecenyl acetate. The evidence for the presence of (Z)-5-decenyl acetate in the pheromone washes was inconclusive. The presence of (Z)-7- and the absence of (Z)-8-dodecenyl acetates were confirmed by a special electroantennographic detector technique in which the detector antennae were from males of other species that were known to have strong responses to these acetates. This is a very useful technique. Field results show that low concentrations (0.1–1.3%) of (Z)-5-decenyl acetate were synergistic when tested in a previously reported blend, but 6% was inhibitory. Similarly, (Z)-7-dodecenyl acetate at 2% or less may be essential for the attraction of males, but in previous tests at 14% it also was inhibitory. Species-specific attractant blends for redbacked cutworm males are described.Lepidoptera: Noctuidae     

Synthesis of epothilone analogues by antibody-catalyzed resolution of thiazole aldol synthons on a multigram scale. Biological consequences of C-13 alkylation of epothilones

Three monoclonal aldolase antibodies (84G3, 85H6, and 93F3), generated against a beta-diketone hapten (II) by the reactive immunization technique, catalyzed highly enantioselective retro-aldol reactions of the racemic thiazole aldols 13-20. Antibody 84G3 (0.0004-0.005 mol%) was used to resolve (+/-)-13-(+/-)-18 to afford compounds 13-18 in multigram quantities. Multiple 13-alkyl analogues of epothilone (7-12) and their trans isomers ((E)-7-(E)-12) were synthesized starting from thiazole aldols 13-18. Construction of the trisubstituted olefin moiety in compounds 7-12 and (E)-7-(E)-12 was catalyzed by Grubbs' catalyst (X). Initial biological testing with compounds 7-10 and their trans isomers showed that compounds 9, 10, and (E)-10 have appreciable tubulin polymerization and antiproliferative activities that approached those of epothilone C. The most active compound, (E)-9, even displayed potencies comparable to those observed for epothilones A and D. Interestingly, all trans analogues were more potent than their corresponding cis isomers. While introduction of an alkyl group at C-13 in the cis series led to an overall reduction in biological activity (compared to epothilone C), appropriate modification of the thiazole moiety (replacement of the 2-methyl substituent by a 2-methylthio group) was able to compensate for this loss. These results are encouraging in view of the expectation that epoxidations of these compounds should further increase their cellular activities. Thus, compounds 9, 10, and (E)-9 and (E)-10 represent highly promising candidates for further studies.     

Design and development of a multichannel potentiometer for monitoring an electrode array and its application in flow analysis

A versatile potentiometer that works with electrode arrays in flow injection and/or monosegmented flow systems is described. The potentiometer is controlled by a microcomputer that allows individual, sequential multiplexed or random accesses to eight electrodes while employing only one reference electrode. The instrument was demonstrated by monitoring an array of seven flow-through ion-selective electrodes for Ag(+) and for three electrodes for Cl(-), Ca(2+) and K(+). The figures of merit of the individual and multiplexed (summed) readings of the electrode array were compared. The absolute standard deviation of the measurements made by summing the potential of two or more electrodes was maintained constant, thus improving the precision of the measurements. This result shows that an attempt to combine the signals of the electrodes to produce a more intense signal in the Hadamard strategy is feasible and accompanied by a proportional improvement in the precision of individual measurements. The preliminary tests suggest that the system can allow for 270 determinations per hour, with a linear range from 1.0 x 10(-2) to 1.0 x 10(-4) mol l(-1) for the three di inverted exclamation markerent analytes. Detection limits were estimated as 3.1 x 10(-5), 3.0 x 10(-6) and 1.0 x 10(-5) mol l(-1) for Cl(-), Ca(2+) and K(+), respectively.     

利用旗形内插件强化气体传热

利用旗形元件强化管内空气强制对流传热,在实验条件下雷诺数的范围为2100～62000。实验结果表明,插入此种元件后可使下游相当于8～10倍管直径的距离内的传热系数较光管提高50～120％,而阻力仅上升10～40％,显然这是一种有效的强化传热的内插件。     

A novel genetic selection system for improved enantioselectivity of Bacillus subtilis lipase A

In directed evolution experiments, success often depends on the efficacy of screening or selection methods. Genetic selections have proven to be extremely valuable for evolving enzymes with improved catalytic activity, improved stability, or with altered substrate specificity. In contrast, enantioselectivity is a difficult parameter to select for. In this study, we present a successful strategy that not only selects for catalytic activity, but for the first time also for enantioselectivity, as demonstrated by the selection of Bacillus subtilis lipase A variants with inverted and improved enantioselectivity. A lipase mutant library in an aspartate auxotroph Escherichia coli was plated on minimal medium that was supplemented with the aspartate ester of the desired enantiomer (S)-(+)-1,2-O-isopropylidene-sn-glycerol. To inhibit growth of less enantioselective variants, a covalently binding phosphonate ester of the opposite (R)-(-)-1,2-O-isopropylidene-sn-glycerol enantiomer was added as well. After three selection rounds in which the selection pressure was increased by raising the phosphonate ester concentration, a mutant was selected with an improved enantioselectivity increased from an ee of -29.6 % (conversion 23.4 %) to an ee of +73.1 % (conversion 28.9 %) towards the (S)-(+)-enantiomer. Interestingly, its amino acid sequence showed that the acid of the catalytic triad had migrated to a position further along the loop that connects beta7 and alphaE; this shows that the position of the catalytic acid is not necessarily conserved in this lipase.     

五氧化二磷测定方法的比较

通过对磷钼酸喹啉重量法、磷钒钼黄比色法、磷钒钼黄改进比色法、螯溶-差示光度法4种测定P2O5含量方法的对比分析,研究几种比色测定方法的可靠性和准确性.实验结果表明以酸溶-重量法实验结果为基准,当分析样品单一且其P2O5含量较低时,可选用磷钒钼黄比色法;如分析样品含磷量变化大,应采用改进磷钒钼黄比色法;如测定高品位磷矿中的磷含量,可用螯溶-差示光度法.     

自组装多肽水凝胶支架中MSCs的三维培养及成骨分化

使用一种新型人工设计自组装多肽(RADA16)水凝胶作为三维培养支架评价MSCs成骨分化情况。将人骨髓MSCs培养增殖后接种到水凝胶中,在成骨分化培养液中进一步培养1～3周。荧光染色法观察细胞形态和存活情况;组织学染色检测MSCs ALP活性;半定量RT-PCR分析成骨特异性基因的表达。绝大多数MSCs在水凝胶支架内能够存活,呈纺锤样形态。诱导培养后蛋白和基因表达水平均检测到ALP活性,在14天时达到峰值。骨晚期分化特异性基因BSP也有表达,且表达量随培养时间延长而增多。自组装多肽水凝胶为MSCs的黏附生长及向成骨细胞分化提供良好的三维微环境,有望成为极具吸引力的骨组织工程支架材料。