Study on Determination of Chemical Oxygen Demand in Water with Ion Chromatography

A new method for determining chemical oxygen demand （COD） value in water using ion chromatography coupled with nano TiO2-K2S2O8 co-existing system was described. The photocatalytic oxidation system and nano TiO2-K2S2O8 co-existing system could degrade the organic compounds in water. All sulfur-containing species in the reactive solution were eventually transformed to sulfate which could be determined by conductivity detector in ion chromatography. The change of conductivity of sulfate was proportional to COD value. The optimal experimental conditions and the mechanism of the detection were discussed. The application range was 10.0-300.0 mg·L^-1 and the lowest limit of detection was 3.5 mg·L^-1. It was considered that the value obtained could be reliably correlated with the COD value obtained using the conventional methods.     

吸附法脱除乙烯中少量氮气的研究

采用重量法在电子天平上，研究了C2H4和N2单组分在5A、13X、丝光沸石和炭分子筛不同吸附剂上的吸附平衡性质和扩散动力学性质。单柱模拟变压吸附评价了炭分子筛吸附脱除C2H4-N2（N2为4．7％）混合组分中N2的性能，并对流速和压力的影响进行了考察。研究表明，该炭分子筛是吸附脱除C2H4中少量N2的理想吸附剂。     

静电纺丝辅助后处理合成钴氮共掺杂碳纤维用于氧还原催化剂

通过静电纺丝辅助后处理策略开发了Co和N掺杂碳纳米纤维(N-Co@CNFs)的高效ORR催化剂.该方法可以有效提高氮的掺杂水平,优化氮掺杂位的状态,生成高活性的石墨氮主导位点,提高碳纳米纤维骨架的石墨化程度.同时,在一维碳纳米纤维的独特高度开放的骨架上实现高活性的氮掺杂位点和钴基位点合理整合.这种独特的纳米结构使得制备的N-Co@CNF具有优异的电催化活性、四电子选择性和在碱性电解质中的稳定性.     

荧光法测定水样中痕量硒的消化方法研究

研究了４种消化液消化水样时硒的挥发损失及价态转化，确定了ＨＮＯ３－ＨＣｌＯ４ 荧光法测定水样中痕量总硒及硒价态的最佳消化液，硒的回收率为９８％～１０１％，各种水样及肝肝经该消化液消化后测定，结果令人满意。     

硫酸钡比浊法测定食盐中硫酸根

用硫酸钡比浊法测定硫酸盐,大多采用甘油、明胶或乙醇作稳定剂,为保证分析结果的再现性,均需严格控制电磁搅拌时间、搅拌速度、固体氯化钡的粒度和试剂加入顺序。本试验改用吐温-80作稳定剂,使方法对操作条件无苟刻要求,手续较简便,结果再现性好,相对标准偏差1.8％;方法加标回收率为99.5％～102％。 1 试验部分 1.1 试剂与仪器 BaCl_2-吐温溶液:BaCl_2·2H_2O溶液(12％)80ml和吐温-80 20ml混合。 硫酸盐标准液:经105℃干燥的优级纯K_2SO_41.8141g或Na_2SO_41.4787g,水溶解后定容于1000ml量瓶中,分液,准确稀释10倍得SO_4~(2-)0.1mg·ml~(-1)工作液。 53W型紫外可见分光光度计(上海光学仪器厂) 1.2 试验方法 准确称取食盐样品2g于烧杯中,加水约50ml,加热溶解,滤入200ml量瓶中,洗涤后,以水定容至200ml。准确分液5～50ml于50ml具塞比色管中,加水至50ml,加HCl(1+1)和BaCl_(2-)-吐温溶液各2.5ml,倒转数次混匀,10min,在720nm处,用3cm比色皿,以水作参比,测吸光度。 标准曲线绘制:分别取SO_4~(2-)0、0.4、0.6……1.5mg于一组50ml比色管中,加水至50ml后,按上述样品分析操作。     

外消旋Euphraticol及其类似物的全合成

研究了外湖旋euphraticol及其类似物的全合成。可成为松香烷二萜的新的有效合成路线。关键步骤是烯醇醚与螺[1,3-苯并间二氧环戊烯-2,1'-环己烷]类的碘化物在HMPA存在时的烷基化反应。     

溶剂萃取对烟煤孔隙结构和粒度的影响

用二硫化碳-N-甲基-2-吡咯烷酮（CS2-NMP）(1∶1, V/V) 混合溶剂、丙酮和吡啶对南桐烟煤逐级萃取，得到各级残余物。通过比表面积及孔快速测试仪和扫描电镜，对煤及各萃取残余物的氮气吸附行为、粒度进行测试，考察了溶剂萃取对煤的BET比表面积与BJH孔容、孔面积随孔径分布规律以及粒度的影响。结果表明通过“溶解”小分子物质，溶剂萃取能够有效地改善煤的吸附性、比表面积和孔隙结构，降低其粒度，但不能破坏其基本结构单元，在本质上仍属于物理作用。根据最可几孔径计算出南桐烟煤胶态分子团结构模型中基本结构单元的粒径在3.5 nm左右，证实了煤分子胶态团结构模型的假设。     

Electronic spectroscopy and photochromic mechanism of bis-Schiff bases, N, N''''-bis(2-hydroxy-1-naphthylidene)-1,4-phenyldiamine

The steady state and transient state absorption spectra and fluorescence spectra of N,N'-bis(2-hy-droxy-1-napbthylidcne)-1,4-phenyldiamme ( BNP ) in cyclohexane and acetonitrile were determined.The pho-tochromic mechanism was discussed In nonpolar solvents,BNP exists mainly in the enol form and has the absorption maximum in the UV region In polar solvents,however,both the enol and proton transfer tautomer are formed,but the farmer is the main one Fluorescence emissions result from the excited state of proton transfer product.     

A Facile Approach to Synthesis of the Di-O-methyl Ethers of （-）-Agatharesinol, （-）-Sugiresinol, （＋）-Nyasol and （＋）-Tetrahydronyasol

The facile enantioselective synthesis of the di-O-methyl ethers of （-）-agatharesinol （1b）, （-）-sugiresionl （2b）, （＋）-nyasol （3b） and （＋）-tetrahydronyasol （4） were achieved in high yield. The absolute configuration of （＋）-3a was confirmed via first total synthesis of （＋）-3b and （＋）-4.     

TOTAL SYNTHESIS OF Trichosanthes TRYPSIN INHIBITOR AND ITS ANALOGUE

Trichosanthes trypsin inhibitor (TTI) is a peptide consisting of 27 amino acid residues with three pairs of disulfide bonds. This paper reports the total synthesis and disulfide bond refolding of this inhibitor and its analogue. After purification, the amino acid sequence and stoichiometrical inhibitory activity against trypsin of the synthetic inhibitor were compatible with those of the natural inhibitor. The analogue of this inhibitor in which residue Met in position 6 was replaced by Ala was also synthesized. The antitrypsin activity of this synthetic analogue was also approximate to that of the natural inhibitor.