Intensified reactive extraction of 4-hydroxypyridine with di(2-ethylhexyl) phosphoric acid in 1-octanol by using tributyl phosphate

The efficient separation of amphoteric organic compounds from dilute solutions is of great importance in the industrial field. In the present work, the reactive extractions of 4-hydroxypyridine(4-HP) with tributyl phosphate(TBP), di(2-ethylhexyl) phosphoric acid(D2EHPA) and TBP + D2EHPA dissolved in 1-octanol were investigated, respectively. The influences of the initial concentrations of TBP, D2EHPA and TBP + D2EHPA on distribution ratio(D) were discussed, as well as the reactive extraction mechanism were proposed. The obvious intensification effect was observed when the mixture of TBP and D2EHPA was used as extractant. The best extraction conditions were found to be of the molar ratio of D2EHPA and TBP at 2:1 and the equilibrium aqueous pH at 3.50-4.50. D values increased with the increase of the total concentration of TBP and D2EHPA in 1-octanol. Especially, the analysis on the extraction mechanisms clearly indicate(i) TBP in 1-octanol shows negligible reactive extraction toward 4-HP,(ii) D2EHPA in 1-octanol exhibits moderate extraction effect by forming 4-HP:D2EHPA(1:1) and 4-HP:2D2EHPA(1:2) type complexes, while(iii) D2EHPA in TBP/1-octanol demonstrates the maximum distribution ratio with the 4-HP:D2EHPA(1:1) type complex domination. The discussion provides new insights on the mechanism and opens a new way for the intensified extraction of amphoteric organic compounds by using the mixture of multiple extractants in the diluent.

Enantioselective esterification of(R,S)-2-(4-methylphenyl)propionic acid via Novozym 435:Optimization and application

This paper reports on the resolution of(R,S)-2-(4-methylphenyl)propionic acid(MPPA)enantiomers by enzymatic esterification in organic solvent.Novozym 435(CALB)has the best catalytic performance compared with other lipases.Of the alcohols screened,n-hexanol is the best acyl acceptor and gives the highest enzyme activity and enantioselectivity in n-hexane.Response surface methodology(RSM)was used to evaluate the influence of the factors,such as temperature,enzyme amount,substrate concentration and reaction time on the substrate conversion(c)and enantiomeric excess(ee).The correlation coefficient R2 for enantiomeric excess and the conversion are 0.9827 and 0.9910,respectively,indicating that can accurately predict the experimental results.By simulation and optimization,the optimal conditions were obtained,involving 600 mmol·L^-1 MPPA concentration(0.60 mmol),850 mmol·L^-1 hexanol concentration(0.85 mmol),58 mg enzyme amount,75℃temperature and 4.5 h reaction time,respectively.Under the optimized conditions,the experimental values of conversion and enantiomeric excess were 89.34%and 97.84%,respectively,which are in good agreement with the model predictions.

Hydrothermal Syntheses and Crystal Structures of Six Complexes Constructed from 1,3,5-Benzenetricarboxylic Acid and 4'-(4-Pyridyl)-2,2':6',2''-terpyridine Mixed Ligands

Six new transition metal complexes, [Zn（HBTC）（PYTPY）]n·n PYTPY（1）, [Cu（HBTC）（PYTPY）]n·n PYTPY（2）, [Co（HBTC）（PYTPY）]n·n DMF（3）, [Mn（HBTC）（PYTPY）]n·n DMF（4）, [Cd（HBTC）（PYTPY）（H2O）]n·2nH2O（5）, and [Co（HBTC）（PYTPY）（H2O）2]（6）,（H3BTC = 1,3,5-benzenetricarboxylic acid, PYTPY = 4＇-（4-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, DMF = N,N？-dimethylformamide）, have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Complexes 1~5 all feature one-dimensional chain structures, and complex 6 exhibits a zero-dimensional structure. Complexes 1~5 present three-dimensional（3D） supramolecular frameworks via π-π stacking interactions, whenas 6 has also a 3D supramolecular structure assembled by hydrogen bonding. Meanwhile, complexes 1 ~ 6 exhibit the thermal stabilities and photoluminescent properties.

Metal-directed Assembly of Two Distinct Coordination Polymers with 2,5-Furandicarboxylic Acid and 4,4'-Bipyridine

By using solvothermal method, two new metal coordination polymers based on 2,5-furandicarboxylic acid（H2FDA） ligand and 4,4＇-bipyridine（bipy）, [Cu（FDA）（4,4＇-bipy）（DMF）]n·solvent（1） and {[Zn（4,4＇-bipy）（FDA）（DMF）]·DMF}n（2）, were produced and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR and powder X-ray diffraction. Compound 1 crystallizes in monoclinic space group P21/c with a = 11.104（2）, b = 10.396（2）, c = 18.772（4） , β = 96.20（3）o, V = 2154.2（7） 3, Dc = 1.378 g/cm^3, C19H17 Cu N3O6, Mr = 446.90, F（000） = 916, μ（Mo Kα） = 1.05 mm^-1, Z = 4, R = 0.0691 and wR = 0.1341 for 3537 observed reflections（I 2σ（I））, and R = 0.1062 and w R = 0.1482 for all data. Compound 2 crystallizes in monoclinic space group C2/c with a = 29.779（6）, b = 9.6417（19）, c = 17.292（3）, β = 105.69（3）°, V = 4779.9（16） 3, Dc = 1.445 g/cm^3, C22H22N4O7 Zn, Mr = 519.81, F（000） = 2144, μ（Mo Kα）= 1.08 mm^-1, Z = 8, R = 0.0641 and w R = 0.1007 for 2985 observed reflections（I 2σ（I））, and R = 0.1028 and w R = 0.1112 for all data. Different coordination geometry of metal ions, square pyramid of Cu2＋ and trigonal bipyramid of Zn2＋, bring about different orientations of FDA2- ligands as well as 4,4＇-bipyridine ligands, and furthermore distinct assembly structures for 1 and 2. The thermal stabilities of 1 and 2 are also investigated.

Syntheses, Structures and Photoluminescence of the Cadmium(Ⅱ) and Copper(Ⅱ) Complexes Based on 4'-(4''-Pyridyl)-2,2':6',2''-terpyridine and 1,4-Benzenedicarboxylic Acid Ligands

Two new metal-organic complexes [Cd2（1,4-BDC）（4-pytyp）（H2O）4]·（1,4-BDC）（1） and [Cu2（1,4-BDC）（4-pytyp）2（H2O）2]·（1,4-BDC）·8H2O（2）（4-pytyp = 4＇-（4＇＇-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, 1,4-H2 BDC = 1,4-benzenedicarboxylic acid） have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared analysis and X-ray single-crystal diffraction. The scrutiny of single-crystal structure reveals that complex 1 forms to a 3D supramolecular network linked by π-π stacking interactions and hydrogen bonds. X-ray diffraction analysis reveals that complex 2 exhibits a 3D supramolecular network linked through complicated hydrogen bonds. The thermogravimetric analysis and photoluminescent properties of 1 and 2 are discussed in detail.

Synthesis and Crystal Structure of 4-(4,6-dimethoxyl -pyrimidin-2-yl)-3-thiourea Carboxylic Acid Methyl Ester

The title compound 4-（4,6-dimethoxylpyrimidin-2-yl）-3-thiourea carboxylic acid methyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at the room temperature. The structure was characterized by elemental analysis and IR and determined by X-ray diffraction analysis＇ Crystallographic data： C9H12N4O4S, Mr = 272.29, monoclinic, space group C2/m with a = 1.6672（3）, b = 0.66383（12）, c = 1.1617（2） nm, β = 109.275（2）°, V = 1.2136（4） nm^3, Dc = 1.490 g/cm^3,μ = 0.281 mm^-1, F（000） = 568, Z = 4, R1 = 0.0341and wR2 = 0.1042.

Synthesis, Resolution, and Enantiomeric Purity Assay of 2-n-Butylbutanedioic Acid 4-t-Butyl Esters

Racemic 2-n-butylbutanedioic acid 4-t-butyl esters were synthesized from methyl hexanoate and t-butyl α-iodoacetate via alkylation and subsequently selective hydrolyzation. The （R）-and （S）-2-n-butylbutanedioic acid 4-t-butyl esters were obtained by the resolution of the above-mentioned racemic compounds with（S）-（ - ） or（R）-（ ＋ ）-α- methylbenzylamine, respectively. The e.e. values of the two optical active products were determined to be above 99% by HPLC after the formation of two pairs of diastereoisomers with（R）-（ ＋ ）-α-methylbenzylamine and（S）- phenylalanine methyl ester.

Syntheses and antimicrobial activities of amide derivatives of 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid

Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial activities. Compounds 2 (96.5%) against Aspergillus fumigatus and 6 (93.7%) against Helminthosporium sativum demonstrated excellent activities. However, compounds 3 (37.6%) against Bacillus subtilis, 4 (33.2%) against Pseudomonas aurignosa, 5 against Klebsiella pneumonia demonstrated excellent growth inhibition potential.

Synthesis and Crystal Structure of 4-(4,6-Dimethoxylpyrimidin-2-yl)-3-thiourea Carboxylic Acid Ethyl Ester

4-（4,6-Dimethoxyl-pyrimidin-2-yl）-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at room temperature. The crystal structure was determined by X-ray diffraction analysis. Crystallographic data： C10H14N4O4S, M, = 286.31, monoclinic, space group C2/c with a = 2.5309（3）, b = 0.67682（6）, c = 1.74237（19） nm, β = 114.744（3）°, V= 2.7106（5） nm3, Dc = 1.403 g/cm3, p = 0.225 mm-1, F（000） = 1200, Z= 8, R= 0.0514 and wR= 0.1529.

Metal-organic frameworks derived from divalent metals and 4-(1H-1, 2, 4-triazol-1-yl)benzoic acid

Two inorganic-organic coordination polymers, [Cd(TBA)2]·3H2O (1) and [Cu(TBA)2]·2H2O (2) have been synthesized by reaction of the metal ions of Cd(II) and Cu(II) with the ligand HTBA [HTBA = 4- (1H-1, 2, 4-triazol-1-yl)benzoic acid] under solvothermal condition. The compounds were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, X-ray powder diffraction (XRPD), and thermo gravimetric analysis (TGA). The structural analyses reveal the two independent polymers exhibit different structures. Complex 1 exhibits a 3D framework with 1D channels, and complex 2 shows a 2-fold interpenetrating 3D diamond net.

Protective Effect of <i>Lepedium sativum</i>against 2, 4-Dichlorophenoxyacetic Acid Hepatotoxicity: An Electron Microscopic Study

Medicinal plants have been used to treat many diseases with fewer side effects compared to clinical medicines. The need for treatment by medicinal plants has been increasing in response to the accumulation of environmental pollutants. The herbicide 2, 4-Dichlorophenoxyacetic acid has been considered as fast spreadable environmental pollutant, which may cause many disorders in animals and possibly in humans. The aim of this study is to assess the protective and/or curative effect of Lepidium sativum against hepatotoxicity induced by 2, 4-D herbicide in rats. 25 Albino Wistar rats were grouped into 4 groups: a control group, the curative group treated for 4 weeks with LS water extract after a single dose 2, 4-D LD50 administration, protective group which was treated for 4 weeks with LS water extract prior to the 2, 4-D LD50 administration, and LS only group that was given the LS water extract as a positive control. Using transmission electron microscope, the histological features showed that curative group hepatocytes still suffered from focal necrosis and vacuolation of hepatocytes as a result of 2, 4-D toxic effect whereas in the protective group hepatocytes were less accentuated expressed as less frequent necrotic area, and still large mitochondria were present with numerous undissolved lipid droplets and a small amount of rough endoplasmic reticulum. For the LS only group, nearly normal cells with centric nucleus, normal small mitochondria were at a normal nucleus-cytoplasmic ratio, but a few lipid droplets were noticed. This study proved that curative group has an advantage over the protective group that could be presented in the nucleus with narrow nuclear pores and intact nuclear envelope with dense small mitochondria and normal rough endoplasmic reticulum that were recorded as in the control group. Thus, Lepidium sativum administration to the rats prior or post to intoxication was effective in minimizing the 2, 4-D-induced damages likely through a free radical scavenging activity in liver tissue.

Structure and Luminescent Property of a Novel 4-Hydroxyquinoline-2-carboxylate Based Zn(Ⅱ) Complex

A 3D coordination polymer [Zn2（hqc）2（H2O）]n has been obtained from the reaction of 4-hydroxyquinoline-2-carboxylic acid （H2hqc） with zinc（II） salt under hydrothermal condition, and characterized by elemental analysis, IR, TGA, PXRD and X-ray single-crystal diffraction. The complex crystallizes in the monoclinic system, space group P21/c with a = 14.305（2）, b = 9.132（2）, c = 15.356（2）, β = 103.586（7）o, V = 1949.9（4）3, Z = 4, Dc = 1.782 g/cm3, μ = 2.508 mm-1, Mr = 523.06, F（000） = 1048, T = 293（2） K, λ（MoKα） = 0.71073, S = 1.008, the final R = 0.0329 and wR = 0.0745 for 3849 observed reflections （I 〉 2σ（I））. The title complex features a 3D framework via Zn（2） linking the 1D {Zn1（hqc）2}n chains. Thermogravimetric analysis shows that its framework is highly thermally stable up to 556 ℃ in the solid state.

Synthesis, Structure and Photoluminescence of a New Cd(Ⅱ) Coordination Polymer Based on 4-(Carboxymethoxy)-benzoic Acid and 1,10-Phenanthroline Derivative

A new ID coordination polymer, [Cda（L1）2（L2）2].H2O （1, H2L1 = 4-（carboxy- methoxy）benzoic acid and L2 = 2-（4-fluorophenyl）-I H-imidazo[4,5-f][1,10]phenanthroline）, has been hydrothermally synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 9.985（5）, b = 10.768（5）, c = 12.512（5） A, a = 68.959（5）, β = 80.354（5）, γ = 79.663（5）°, V= 1227.4（10） A3, Z = 1, C56H36Cd2F2N8O11, Mr = 1259.73, Dc = 1.704 g/cm3, F（000） = 630, μ（MoKa） = 0.949 mm-1, R = 0.0261 and wR = 0.0655. The L1 anions link the neighboring Cd（II） atoms to form a 1D double chain structure. The L2 ligands are alternately located on both sides of the double chains. More interestingly, the lateral L2 ligands from adjacent double chains are paired to furnish strong π-π interactions, yielding a 2D supramolecular layer. N-H...O, O-H...N and O-H...O hydrogen bonds further stabilize the structure of 1. The luminescent property of 1 was studied in solid state at room temperature.

The Selective Reduction of 4-Propylthio-2-nitroaniline with CO Using Ru_3(CO)_(12)/PEDPA Complex as Catalyst

The Ru3(CO)12/PEDPA complex was firstly applied in the CO selective reduction of 4-propylthio-2-mitroaniline. The effects of reaction temperature, the pressure of CO and concentration of catalyst on the reduction were investigated. Under the optimum conditions of T=140℃, Pco=5.0MPa and substrate/catalyst = 300 (molar ratio), the conversion and selectivity were 70% and 98%, respectively. After simple phase separation, the catalyst could be recycled.

2型糖尿病伴干眼症病人血清和泪液分泌型卷曲相关蛋白5、脂肪酸结合蛋白4水平与病情严重程度的相关性

目的分析分泌型卷曲相关蛋白5(SFRP-5)、脂肪酸结合蛋白4(FABP4)在2型糖尿病(T2DM)伴干眼症病人血清和泪液中的表达及其与病情严重程度的相关性。方法选取2020年12月至2021年12月唐山市眼科医院收治的T2DM病人145例,其中单纯T2DM病人84例168眼(T2DM组),伴干眼症病人61例122眼(T2DM伴干眼症组),另选取同期该院体检健康者50例100眼作为对照组。T2DM伴干眼症病人又分为轻度组(29例)、中度组(17例)、重度组(15例)。利用酶联免疫吸附法测定所有受试者血清和泪液中SFRP-5、FABP4水平;相关性分析采用Pearson法或Spearman法;logistic回归分析影响T2DM病人干眼症发生的因素。结果T2DM伴干眼症组、T2DM组血清和泪液SFRP-5水平均低于对照组(106.09±8.37、135.72±9.26比158.34±9.45,28.85±5.13、58.27±6.14比45.18±5.92),T2DM伴干眼症组低于T2DM组(P<0.05);T2DM伴干眼症组、T2DM组血清和泪液FABP4水平均高于对照组(70.63±6.59、58.27±6.14比45.18±5.92,15.91±3.76、10.28±3.58比7.72±3.29),T2DM伴干眼症组高于T2DM组(P<0.05)。重度组、中度组血清和泪液SFRP-5水平(68.29±7.15、95.54±8.34比131.82±9.02,12.83±4.62、24.72±5.49比39.56±5.18)、泪膜破裂时间(BUT)、泪液分泌试验(SIT)低于轻度组,重度组低于中度组(P<0.05);重度组、中度组血清和泪液FABP4水平(84.56±6.83、73.18±6.94比61.93±6.27,25.64±4.19、17.15±3.86比10.16±3.47)及眼表疾病指数量表(OSDI)积分高于轻度组,重度组高于中度组(P<0.05)。T2DM伴干眼症病人血清与泪液SFRP-5水平呈正相关,血清与泪液FABP4水平也呈正相关(P<0.05)。T2DM伴干眼症病人血清和泪液SFRP-5水平与OSDI积分均呈负相关,与BUT、SIT均呈正相关(P<0.05);血清和泪液FABP4水平与OSDI积分均呈正相关,与BUT、SIT均呈负相关(P<0.05)。血清和泪液SFRP-5水平是影响T2DM病人干眼症发生的独立保护因素,而血清和泪液FABP4水平是独立危险因素(P<0.05)。结论SFRP-5在T2DM伴干眼症病人血清和泪液中均低表达,FABP4均高表达,二者与病情严重程度密切相关。

Ni/ZrO_(2)-SO_(4)^(2-)催化剂的制备及其催化甲烷与CO_(2)制乙酸性能

以Zr(NO_(3))4·5H_(2)O和Ni(NO_(3))2·6H_(2)O为原料、(NH4)2CO_(3)为沉淀剂,采用溶胶凝胶-硫酸酸化两步法制备了Ni/ZrO_(2)-SO_(4)^(2-)催化剂,采用XRD,FTIR,SEM,N_(2)吸附-脱附,H_(2)-TPR,NH3-TPD等方法对Ni/ZrO_(2)-SO_(4)^(2-)催化剂进行表征,考察了Ni的引入方式对催化剂的结构和性能的影响。实验结果表明,与共沉淀方式引入Ni制备的Ni/ZrO_(2)-SO_(4)^(2-)催化剂相比,采用溶胶凝胶方式引入Ni制备的催化剂的四方相ZrO_(2)占比更高,表面酸量更多,且具有良好的热稳定性和较强的L酸性;采用溶胶凝胶方式引入Ni制备的Ni/ZrO_(2)-SO_(4)^(2-)催化剂的乙酸生成量明显优于共沉淀方式引入Ni制备的Ni/ZrO_(2)-SO_(4)^(2-)催化剂。四方相ZrO_(2)、酸性位点和过渡金属Ni之间的协同作用促进了甲烷与CO_(2)直接反应合成乙酸。

新标09CrCuSb耐酸钢的耐50%H_(2)SO_(4)腐蚀性能

通过电化学测试和全浸腐蚀试验,研究了不同温度(25,50,60,70℃)条件下新标09CrCuSb耐酸钢在50%H_(2)SO_(4)溶液中的腐蚀行为。结果表明:随着温度从25℃升至70℃,新标09CrCuSb钢的腐蚀速率整体呈现增大趋势,在70℃时,腐蚀速率达到最高,为2.70 g/(m^(2)·h),这与随温度升高,腐蚀产物中具有保护性作用的Fe_(3)O_(4)含量减少,无保护作用的FeSO_(4)·H_(2)O含量增加以及锈层中微孔变化有关。另外,由于新标调整了09CrCuSb钢中Cu、Mo、Sn、Sb、W等元素的含量,与旧标09CrCuSb钢相比,阳极维钝电流密度J维钝降低,同等温度条件下,新标09CrCuSb钢的耐蚀性得到较大改善。

脂肪酸结合蛋白4在2型糖尿病肾病中的诊断价值

目的:探讨2型糖尿病(type 2 diabetes mellitus,T2DM)患者血清脂肪酸结合蛋白4(fatty acid-binding protein 4,FABP4)与糖尿病肾病(diabetic nephropathy,DN)的相关性及其作为DN早期诊断的应用价值。方法:纳入T2DM患者218例及健康体检者(对照组)20名,收集受试者的一般临床资料如身高、体质量、腰围、糖尿病病程等,计算BMI;收集血糖、糖化血红蛋白、空腹胰岛素、空腹C肽、肝肾功能、血脂等指标,计算稳态模型胰岛素抵抗指数(homeostasis model assessment-insulin resistance index,HOMA-IR)。采用ELISA测定血清FABP4水平;采用联合血肌酐(serum creatinine,Scr)和胱抑素C(cystatin C,Cys C)的慢性肾脏病流行病学协作方程式计算肾小球滤过率;测定尿白蛋白和肌酐水平,计算尿微量蛋白与肌酐比值(urinary albumin to creatinine ratio,UACR)。根据估算的肾小球滤过率(estimated glomerular filtration rate,eGFR)水平将T2DM患者分为肾功能正常组(eGFR≥90 mL/min/1.73 m^(2))、轻度肾功能不全组(eGFR 60~<90 mL/min/1.73 m^(2))和中度肾功能不全组(eGFR 30~<60 mL/min/1.73 m^(2));根据UACR水平分为正常蛋白尿组(UACR<30 mg/g)、微量蛋白尿组(UACR 30~<300 mg/g)和大量蛋白尿组(UACR≥300 mg/g)。采用回归分析评估FABP4与eGFR、UACR严重程度的相关性。结果:(1)与对照组相比,T2DM患者的血清FABP4显著升高。(2)在根据eGFR分层的3个亚组中,随着eGFR的下降,血清FABP4水平显著增加(P<0.001)。但在UACR亚组中差异无统计学意义(P=0.382)。(3)Spearman相关分析显示FABP4与eGFR呈负相关(r=-0.203,P=0.001),与UACR无相关性(r=0.130,P=0.055)。(4)多元线性回归表明,FABP4与eGFR呈独立负相关(r=-0.211,P<0.001),与UACR无相关性(r=-0.047,P=0.534)。(5)ROC曲线显示FABP4诊断DN的最佳截断值为103.9μg/L,AUC为0.745(灵敏度51.2%,特异度92.7%)。结论:T2DM患者血清FABP4水平升高与DN发生发展相关,有可能作为DN早期诊断的生物标志物。

中间体2-氯-4-氟-5-硝基苯甲酸的新合成方法

探索中间体2-氯-4-氟-5-硝基苯甲酸的新合成方法。从4-氟苯胺出发,经过盐酸-双氧水体系氯化、重氮化、氰化、硝化-水解串联反应共4步得到2-氯-4-氟-5-硝基苯甲酸,纯度96.2%,总收率59.2%。新合成方法原材料易得、条件温和,具有工业化应用前景。