催化分光光度法测定微量钯

在硫酸介质中，钯对溴酸钾氧化间硝基偶氮氯膦褪色反应有强烈的催化作用。采用二次通用旋转组合设计方法对实验条件进行了优化。利用优化的结果，建立了催化分光光度法测定钯的新方法，测定了钯碳样品中钯的含量。     

人工神经网络-分光光度法同时测定废水中的金和钯

贵金属金和钯都能与新试剂5-（2-羟基-3，5-二甲基苯偶氮）罗丹宁（HD—PAR）形成稳定的红色络合物，由于二者吸收峰严重重叠，采用化学计量学中的人工神经网络方法实现了金和钯的同时测定，方法可用于废水中金和钯的同时测定。     

络合滴定法测定银钯焊料中钯

文献[1—4]报导了在纯溶液中或在铂族金属存在下,用络合直接滴定或返滴定法测定钯。Raoot提出,用硫脲作掩蔽剂选择性络合滴定测定钯的方法,并应用于铜钯、钐钯、镍钯、钴钯合金以及其它合金中钯的测定。本文提出,大量银存在下的银钯焊料中钯的络合滴定法。方法简便、快速、准确,用于实际试样分析,结果满意。     

催化动力学光度法测定痕量钯

在磷酸－磷酸二氢钾缓冲溶液中，以钯（Ⅱ）催化次磷酸钠还原罗丹明Ｂ褪色为指示反应，建立了痕量钯的动力学光度分析新方法。在金（Ⅱ）的存在下，检测下限达５×１０＾－１１ｇ／ｍＬ钯（Ⅲ），方法应用于模拟合金样和含钯分子筛中钯的测定。结果满意。     

表面活性剂增敏动力学光度法测定钯

１ 引 言 动力学光度法测定钯已有报道 所用体系主要有两种类型，一种是利用钯催化次磷酸钠还原有色试剂的反应，另一类型是钯的催化氧化反应。近年来，表面活性剂在动力学分析中的应用日益受到重视。它可提高分析的灵敏度和选择性，改善反应条件，简化分析手续等；作者研究发现，钯对高碘酸钾氧化结晶紫（ＣＶ））褪色有催化作用，体系中加入ＳＤＢＳ后，体系的最大吸收波长紫移，测定的灵敏度明显提高，据此建立了测定钯的动力学光度法。２ 实验方法 取两支 １０ｍｌ具塞比色管，于其中一支加入适量钯标准溶液，再分别在两支管中依次加入 …     

石蜡相分光光度法测定微量钯

以石蜡为固体萃取剂，系统地探讨了钯－丁二酮肟（ＤＭＧ） 显色体系在石蜡相最佳显色条件及光度特性。钯的浓度在０～８０ ｍ ｇ／５０ Ｌ范围内符合比尔定律，相关系数ｒ＝ ０．９９９７。方法检出限为１．７５×１０－ ５ｇ／Ｌ。该法选择性好，大多数常见离子不干扰钯的测定，灵敏度比液相光度法高。应用于分子筛中微量钯的测定，结果良好。     

钯（Ⅱ）对钒（V）—锰（Ⅱ）—Tween—20—二安替比林—（间—羟基）—苯基甲？…

在酸性介质中钯（Ⅱ）对Ｖ（Ｖ）－Ｍｎ（Ⅱ）－Ｔｗｅｅｎ－２０－ＤＡｍＨＭ体系显色反应有阻抑作用，基于此建立了一种测定钯的动力学分析方法，并研究了该阻抑反应的动力学参数。方法的线性范围为２０～２４０μｇＰｄ（Ⅱ）／Ｌ检测限为８．４×１０＾－９ｇＰｄ（Ⅱ）／ｍＬ。该体系灵敏度高，稳定性好，用于石钯渣和钯催化剂中钯（Ⅱ）的测定，结果满意。     

二苯硫脲纤维素分离富集原子吸收光谱法测定地质样品中痕量钯

采用自行研究了合成的二苯硫脲纤维素分离富集地质样品中痕量钯，并使用火焰原子吸收光谱法（ＦＡＡＳ）测定，系统研究了二苯硫脲纤维素分离富集钯的各种条件，并将方法应用于地质样品中痕量钯的分析。     

3,5-二氯-PADAT萃取光度法测定钯

3,5-二氯-PADAT作为显色剂已用于水相光度法测定钯,但萃取光度法测定钯尚未见报导。本文参考文献[2]研究了该试剂与钯在强酸性介质中形成络合物的萃取性能及萃取光度法测定钯的实用条件。实验证明,3.5-二氯-PADAT钯形成的紫红色络合物可被异戊醇萃取,钯量在6微克/5毫升异戊醇内服从比尔定律,萃取后的络合物相当稳定。方法应用于工业废水和催化剂中钯的测定,获良好结果。     

丙基萤光酮-阳离子表面活性剂分光光度法测定微量钯

本文提出了用丙基萤光酮-阳离子表面活性剂光度法测定微量钯的新方法。钯(Ⅱ)量在0—14微克/25毫升内符合比尔定律。方法的灵敏度高,摩尔吸光系数为1.12×10~5。经巯基棉分离后,显著提高了方法的选择性。已用本法测定了钯催化剂和钯废水中的微量钯。     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Investigation of adhesion and mobility of polyurethane and epoxy-rubber glues and adhesives

The values of activation parameters in uncured and cured epoxy resins, rubbers, and blends thereof are investigated. The dependences of activation energy and adhesion strength of epoxy-rubber compositions on rubber content are determined. The correlation of adhesion and activation energy values for polyurethane rubber and epoxy-rubber compositions is shown.     

Physical and Chemical Properties of Magnetite and Magnetite-Polymer Nanoparticles and Their Colloidal Dispersions

The properties of polymer-coated magnetite nanoparticles, which have the potential to be used as effective magnetic resonance contrast agents, have been studied. The magnetite particles were synthesized by using continuous synthesis in an aqueous solution. The polymer-coated magnetite nanoparticles were synthesized by seed precipitation polymerization of methacrylic acid and hydroxyethyl methacrylate in the presence of the magnetite nanoparticles. The particle size was measured by laser light scattering. It was shown that the particle size, variance, magnetic properties, and stability of aqueous magnetite colloidal dispersion strictly depend on the nature of the stabilizing agent. The average hydrodynamic radius of the magnetite particles was found to be 5.7 nm in the stable aqueous colloidal dispersion. An inclusion of the magnetite particle into a hydrophilic polymeric shell increases the stability of the dispersion and decreases the influence of the stabilizing agent on the magnetic and structural properties of the magnetite particles as was shown by X-ray diffraction and M?ssbauer and IR spectroscopy, as well as by vibrating sample magnetometry. The variation in the polymeric shell size and the polymer net density can be useful tools for evaluation of the polymer-coated magnetite particles as effective contrast agents. Copyright 1999 Academic Press.     

Electron-density distribution and reactivities of ethynylimidazoles and -pyrazoles

The electron shells of imidazole, pyrazole, and their ethynyl derivatives were calculated by the CNDO/2 method (complete neglect of differential overlap). The dipole moments, ionization potentials, and energies of heterolytic cleavage of the CH bonds of the ethynyl groups were calculated. The results are compared with the experimental data on the reactivities and acidities. The ethynyl substituent is a weak electron acceptor. The donor capacity of the ring correlates with the charges on the corresponding carbon atoms. The 4 and 5 positions of imidazole constitute an exception to this. The energy of heterolytic cleavage of the CH bond decreases as the electronic charge on the ethynyl group increases.     

钨钼杂多酸及其盐与二甲基甲酰胺加合物的制备和性质研究

合成了10种钨钼杂多酸及其盐与DMF的加合物,用IR光谱、Raman光谱、UV光谱、¹HNMR、TG-DTA和X射线衍射方法研究了加合物的性质。加合物中配体DMF以C=O键的氧作为配位原子,与杂多酸中的质子或杂多酸盐中的金属阳离子配合成键。IR光谱中ν_c-o的位移可作为配位键成键强度的判据。     

Mass and NMR spectra of haplophyllidine and perforine and of their derivatives

Conclusions The mass and NMR spectra of haplophyllidine, perforine, and their derivatives have been studied. The influence of the open and cyclic forms of the molecular ion on the nature of the fragmentation has been discussed. The main routes of fragmentation of the compounds considered are due to the presence of substituents at C₈ and C₄.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 273–279, 1969     

Hexane isomerization and cracking activity and intrinsic acidity of H-zeolites and sulfated zirconia-titania

Adsorption of N2 was studied on zeolite H-Y, ultrastabilized H-Y (H-USY), H-mordenite, H-ZSM-5, H-beta, and on sulfated zirconia-titania (SZT) mixed oxide by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) at 298 K and at N2 pressures up to 9 bar. The adsorption-induced DeltanuOH red-shift of the nuOH bands was used as a measure of the intrinsic acid strength of the Brn?nsted acid sites. The intrinsic acid strength of the solids follows the order of H-ZSM-5 approximately H-mordenite approximately H-beta > H-USY > SZT approximately H-Y. The solids were characterized by their hexane conversion activities at 553 K and 6.1 kPa hexane partial pressure. The reaction was shown to proceed predominantly by a bimolecular mechanism, while the reaction was first order in hexane and zero order in alkenes. The site-specific apparent rate constant of the bimolecular hexane conversion was shown to parallel the intrinsic acid strength of the samples, suggesting that the ratio of the apparent and the intrinsic activity, that is, the KA' equilibrium constant of alkane adsorption on the hydrocarbon-covered sorption sites, is hardly dependent on the catalyst structure.     

Hirshfeld surface analysis and spectroscopic and DFT studies of p-acetotoluidide and p-thioacetotoluidide

The Hirshfeld surface analysis, theoretical calculation, and IR and Raman spectra of p-acetotoluidide and p-thioacetotoluidide were reported. Hirshfeld surfaces and fingerprint plot have been used for visualizing, exploring, and quantifying intermolecular interactions in the crystal lattice of the title compounds. The packing of the molecules in the crystal structure of p-acetotoluidide and p-thioacetotoluidide forms the chains of N–H···O and N–H···S hydrogen bonds, respectively. The close contacts are also dominated by H···H and H···C/C···H interactions. The analysis of Hirshfeld surface has been well correlated with the spectroscopic studies. Theoretical calculations of the title compounds’ isolated molecule have been carried out using DFT at the B3LYP level.     

Electronic structure and polarizability of ortho-benzoquinonediimine and its singly and doubly charged anions

The results of electronic structure calculations for o-benzoquinonediimine and its singly and doubly charged anions are presented. The variation of the geometrical and valence structures due to electron addition to the molecule is analyzed, and electron affinity is estimated. Polarizabilities of the neutral molecule and singly charged anion are calculated. The influence of the basis on the results of polarizability calculations for molecular anions is investigated. Translated from Zhumal Struktumoi Khim ii, Vol. 41, No. 1, pp. 34-41, January–February, 2000.