Determination of boron trifluoride in boron trifluoride complex by fluoride ion selective electrode

A method was proposed to determine boron trifluoride in boron trifluoride complex using fluoride ion selective electrode(ISE). Hydroxide was chosen to mask aluminum for the determination of 0.01—0.1 mol/L of fluoride. The simulation indicated that the permissible aluminum masked at a certain p H value was limited and hardly related to F-concentration and boric acid. It is better to control p H value below 11.5 and the aluminum concentration within 0.025 mol/L to minimize the interference of hydroxide to the fluoride ISE. The decomposition conditions of boron trifluoride by aluminum chloride were investigated. It is found that the F-detection ratio will approach 1.0 if the Al/F molar ratio is 0.3—0.7 and aluminum concentration is no more than 0.02 mol/L when heated at 80 ℃ for 10 min. In one word, hydroxide is quite fit to mask aluminum for samples which contain high content of fluoride and aluminum and the BF3 content can be successfully determined by this method.     

Kinetics of the reaction between boron trifluoride methanol complex and sodium methoxide to produce enriched <Superscript>10</Superscript>B methylborate

The relation of boron trifluoride concentration with conductivity in boron trifluoride methanol solution (BF₃-CH₃OH)was power exponent fitted in low concentration range. The kinetics of the reaction between boron trifluoride methanol complex and sodium methoxide to produce enriched ¹⁰B methylborate was proposed based on a detailed mechanism study, and was verified by acid-base titration method and conductivity method. It was found that this reaction is first order reaction and the rate constant is 0.022 min^?1 at 338 K(65 °C), the activity energy is 65 kJ/mol. In addition, it was found that the conductivity method is more feasible to measure the kinetic curve than acid-base titration method.     

HPLC法测定石杉属植物中石杉碱甲的含量

采用YWGC18柱(4.6 mm×250 mm,10μm),以甲醇(80 mmol.L-1)-醋酸铵溶液(pH 6.0)(35:65)为流动相,流速为1.0 mL.min-1;检测波长为310 nm,建立了HPLC法测定湖北利川三种石杉属植物(蛇足石杉、皱边石杉、四川石杉)中石杉碱甲含量,以期发掘替代资源。结果显示,三种石杉属植物中均含有石杉碱甲,且四川石杉最多,蛇足石杉次之,皱边石杉最少,故四川石杉可以作为提取石杉碱甲的原料药材之一,具有较高的开发和利用价值。     

Caffeic acid product from the highly copper-tolerant plant Elsholtzia splendens post-phytoremediation: its extraction, purification, and identification

In the current study, caffeic acid was an important metabolite in the highly copper-tolerant plant Elsholtzia splendens. Preparation and purification of caffeic acid were performed on the dried biomass of the plants by means of sonication/ethanol extraction, followed by purification using a macroporous resin (D101 type) column and silica gel chromatography. The faint-yellow caffeic acid product was yielded with a purity of 98.46%, and it was chemically identified from spectra of Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR)/carbon nuclear magnetic resonance (¹³C NMR), and electrospray ionization mass spectrometry (ESI-MS). Caffeic acid is a possible product from the post-harvest processing of Elsholtzia splendens biomass.     

Equilibrium on the hydrolysis of boron trifluoride in large amount of water

In order to clarify the equilibrium components in the hydrolysis solution of boron trifluoride(BF_3-H_2O),the BF_3-H_2O was prepared by mixing BF_3-CH_3OH with large amount of water,in which the stoichiometric concentration of BF_3 is less than 0.1 mol/L.Two ionic equilibrium models were proposed to simulate the hydrolysis equilibrium of BF_3 and tested by special acid-base titration technique.The most accurate ion equilibrium constants were determined.The model,which was assumed to have no HF,was proved to be more representative for the real system and used to simulate the hydrolysis equilibrium of BF_3.The simulation suggested that H~+,BF_4~-,BF_3OH~- and H_3BO_3 were the main species in the dilute hydrolysis solution,while BF_2(OH)_2~- and F~- were insignificant species whose concentrations were both in the order of 10~(-4) mol/L magnitude,and BF(OH)_3~- could be omitted because its concentration almost equaled zero.Meanwhile,the equilibrium constant of the overall ionic reaction at 25℃ was obtained as 161.6.     

吡啶基苯并咪唑化合物的微波合成及荧光特性

以邻苯二胺、吡啶甲酸为原料,多聚磷酸为催化剂和溶剂,经微波辐射合成了2-（3-吡啶基）苯并咪唑、2-（2-吡啶基）苯并咪唑。通过熔点、元素分析、IR和1H NMR对其纯度和结构进行表征,探讨了目标化合物在微波辐射下合成的工艺条件及荧光特性。     

金属多氧络合物引发异丁基乙烯基醚阳离子聚合研究

以具有特征Keggin晶体结构的金属多氧络合物——磷钼酸为主要催化剂,以三氯甲烷作溶剂,室温引发异丁基乙烯基醚进行阳离子聚合,考察了特效稳定剂——十六烷基三甲基溴化铵对该反应体系的影响,并系统地比较了不同配比条件下进行阳离子聚合的引发效率。     

鸭毛水解生产复合氨基酸的研究

研究了酸、碱条件下不同化学药品对鸡毛降解的影响,并在水解温度恒定、水解剂硫酸3mo1/L或氢氧化钠3mo1/L及常压条件下,采用正交试验研究了固液比、助剂用量、水解时间对水解率的影响。在水解温度110℃及常压条件下,水解剂为3mol/L硫酸处理的最佳水解工艺为固液比1∶15,水解时间11h。3mo1/L氢氧化钠作为水解剂时的最佳水解工艺为固液比1∶15,水解时间10h。     

吡嗪-2-羧酸铜配合物[Cu(C_5H_3N_2O_2)_2]的合成、晶体结构和光谱性质

用吡嗪-2-羧酸合成了配合物[Cu(C5H3N2O2)2],并通过元素分析、红外分析及X-射线衍射对其结构进行了表征.晶体属单斜晶系,空间群为:P2(1)/c,晶胞参数:a=5.0624(9),b=15.414(3),c=7.1110(13),β=106.701(2)°,V=531.48(16)3,Z=2.F(000)=310,吸收系数μ=2.072mm-1,最终偏离因子R1=0.0216,wR2=0.0594.中心铜原子与两个吡嗪-2-羧酸配体形成配合物分子,各分子之间通过弱相互作用形成一维链状结构.     

Clones identification of Sequoia sempervirens (D.Don) Endl.in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D.Don) Endl.in Chile.Ten (out of 34) clones from introduction trial located in Voipir-Viilarrica,Chile,were studied.The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction.The PCR tests were carried out employing 10-mer random primers.The amplification products were detected by electrophoresis in agarose gels.Forty nine polymorphic bands were obtained with the selected primers (BG04,BF07,BF 12,BF13,and BF 14) and were ordered according to their molecular size.The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA).Of the primers tested,5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism.A total of 49 polymorphic RAPD bands were detected out of 252 bands.The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones,suggesting a geographic relationship.The results indicate that the RAPD markers permitted the identification of the assayed clones,although they are derived from the same geographic origin.     

非那甾胺的合成

非那甾胺是一种底物竞争型 5 α-还原酶抑制剂 ,用于良性前列腺增生的临床治疗 .本文提出了一种新的合成方法 ,以孕烯醇酮为原料经 10步反应制得了非那甾胺 ,即季铵化、甲氧基化、Oppenauer氧化、水解、氧化切断 Δ4-双键、氨解环合、Δ5-双键加氢、酯化、A环 1,2位脱氢和 Bodroux反应 .本方法避免了文献中昂贵试剂 2 ,2 -二硫吡啶的使用 .经质谱和 /或核磁共振确定了所有化合物结构 .以孕烯醇酮计 ,非那甾胺的总收率为 13.6 7% .     

微波促纤维素水解制备可发酵还原糖研究

利用生物质纤维素生产燃料乙醇是目前研究的热点,而生物质纤维素乙醇转化技术的关键是如何将纤维素水解为可发酵还原糖.本文对常规加热法与微波幅射法水解纤维素制取还原糖进行了对比研究.实验结果表明,在微波辐射条件下,不仅能获得更高的还原糖收率,糖化时间更是大为缩短,极大地降低了水解过程能耗.     

九钼锰酸铵的合成和动力学测定

以(NH4)6Mo7O24·4H2O,MnSO4·H2O和(NH4)2S2O8为原料合成(NH4)6[MnMo9O32]·8H2O(八水合九钼锰酸铵),用紫外可见电子光谱分析法对该化合物进行表征;以490 nm为测定波长,测定浓度为8×10-4mol/L的(NH4)6[MnMo9O32]溶液与浓度分别为4×10-3、6×10-3、8×10-3、12×10-3 mol·L-1的酒石酸溶液进行氧化还原反应时的吸光度.以不同浓度的In(A-A∞)对T作图呈线型关系,确定氧化剂反应级数为一级反应.以不同浓度的Kobs对还原剂浓度作图,其图形也呈直线,确定还原剂反应级数也为一.     

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin. Project (No. CONICYT-FONDEF PROYECT D01 I 1008) supported by the National Commission of Science and Research of Chile     

金属-有机骨架K-MOF的合成及性质表征

以硝酸钾为中心金属离子,1,4-苯二甲酸（H2BDC）、1,3,5-苯三甲酸（H3BTC）及混合物（H2BDC+H3BTC）为有机配体,N,N-二甲基甲酰胺（DMF）为溶剂,采用溶剂热法合成三种K-MOF晶体。通过X射线粉末衍射(PXRD)、红外光谱(FT-IR)、扫描电镜（SEM）及热重(TG)等方法对样品进行表征,考察不同配体对K-MOF的影响。结果表明:K+与H2BDC配位得到的长条状晶体,与H3BTC配位得到粉末状晶体,H2BDC与H3BTC同时存在时,K+优先与H3BTC配位得到粉末状晶体。K-MOF具有良好的热稳定性,在350℃内能保持结构的热稳定性。     

碘化三甲基对乙酰苯基铵的合成

在乙酸乙酯溶剂中,以碘甲烷和对二甲氨基苯乙酮反应合成了碘化三甲基对乙酰苯基铵,通过红外光谱和核磁共振氢谱表征了其分子结构.结果表明,在碘甲烷过量50%条件下,反应时间4h,生成的产物可自行从溶液中沉淀出来,产率达85%以上。     

一个具有二维结构的四配位金属镍配合物的合成、结构和光致发光性能的研究

四氟硼酸镍溶液与2-吡嗪甲酸反应生成了一个单核配位化合物[Ni(Pz)2](Pz=2-pyrazinecarboxylatic acid)。配合物结构中的单核单元通过T…π堆积作用相互联系在一起,进而向二维空间伸展,构成了配合物[Ni(Pz)2]的二维超分子结构。对配位化合物[Ni(Pz)2]光致发光性能的研究发现,配合物[Ni(Pz)2]又展示出了一个大概位于433 nm的宽阔的发射峰。其荧光发射机理被归属为配体内部的π-π*电子跃迁。     

BF在外电场作用下的分子特性

文章首先采用了多种方法对BF分子基态进行几何优化,在此基础上选用密度泛函理论B3LYP方法结合6-311g(3df,2pd)基组,分别得到了在不同外电场(-0.03—+0.02a.u.)下BF分子的电子结构,讨论了在不同外电场下BF分子的键长、体系能量、电荷分布、频率、偶极矩及能级分布的规律,得出外电场对BF分子的电子结构影响成不对称性。     

酶法水解动物蛋白工艺研究

用三种不同蛋白酶(胰蛋白酶和酸性蛋白酶)对猪肉在不同条件下进行酶解，利用甲醛滴定法对水解效果进行了对比。采用L18(37)确定两种蛋白酶水解猪肉的最佳工艺参数。     

Fabrication of LaAlO3 film by sol-gel process with corresponding inorganic

Well-cubic perovskite lanthanum aluminate (LaAlO3) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate and aluminum nitrate hexahydrate after being refluxed. (CH3CO)2O removed nitrates and the crystallized H2O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)3(x(AcAc)x, which were hydrolyzed into La(AcAc)3(x(OH)x by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)3(x(OH)x, polymerizing and combining with MCL, formed the LaAlO3 sol precursor with heteropolymeric structure and formed film easily. The epitaxial LaAlO3 film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650(750 (C/30 min. The morphologies and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and the dissipation factors were estimated to be 23(26 and 2.1(10(4 ( 2.4(10(4 respectively.