硫酸根型阴离子交换树脂法改善PAC絮凝性能的研究

体系以聚合氯化铝溶液为原料，以硫酸型强碱性阴离子交换树脂为载体，进行离子交换反应。结果表明，在保持氧化铝含量基本不变的情况下，能有效地提高聚合铝的碱化度。同时生成含ＳＯ４＾２－的聚合氯化铝，实验证明它的絮凝效果优于了聚合氯化铝。     

Influence of medium acidity upon the luminescence properties of 2,5-diphenyl-1,3,4-oxadiazole and 2,5-diphenyl-1,3-oxazole

The luminescence properties of 2,5-diphenyl-1,3,4-oxadiazole and 2,5-diphenyl-1,3-oxazole in aqueous solutions of sulfuric acid (pH 7 to H_o − 10) were studied. The spectral parameters are essentially acidity dependent, which is due to the acid-base equilibria of these heterocycles both in the ground and in the first excited singlet states. The difference between these two compounds is governed by their dissimilar solvation. The basicity constants of 2,5-diphenyl-1,3,4-oxadiazole in the S₀ state (pK_BH+ = − 2.49) and 2,5-diphenyl-1,3-oxazole in the S₀ and S₁ states (pK_BH+ = −1.93, pK_BH+^* = 1.95) were experimentally obtained. The enthalpies of formation, electron charge density, and geometry of the bases and corresponding conjugate acids in the S₀ and S₁ states were calculated by the MNDO method.     

Investigation of the structure of and the properties of the potentially tautomeric 1,2,3,4-tetrahydro-5,7-dimethyl-6H-pyrrolo[3,4-d]pyridazine-1,4-diones in the gaseous and aqueous phases using the AM1 semi-empirical method

Potentially tautomeric 1,2,3,4-tetrahydro-5,7-dimethyl-6H-pyrrolo[3,4-d]pyridazine-1,4-diones and their fixed tautomeric forms have been studied in order to predict their tautomeric equilibrium constants and pK_a values using semi-empirical AM1 quantum-chemical calculations at the SCF level in the gas phase and in aqueous solution. Hydroxy-oxo forms were found to be more stable than dioxo and dihydroxy forms. The results obtained from the tautomeric equilibria and basicity calculations are in good agreement with experimental data.     

聚合氯化铝铁溶液的可见光谱与碱化度、总铁浓度关系研究

研究了不同碱化度Ｂ、不同铝铁摩尔比的聚合氯化铝铁（ＰＡＦＣ）溶液的可见光谱。发现它们在４６０ｎｍ波长处吸光度Ａ与溶液的碱化度Ｂ线性相关;用该波长处吸光度Ａ对铝铁摩尔比作图出现的折点与它们的ｐＨ－ｎＡｌ／ｎＦｅ（铝铁摩尔比）曲线上ｐＨ突跃点正好对应。说明这些折点分别代表了不同Ｂ值下溶液中配体ＯＨ＾－在Ｆｅ（Ⅲ）与Ａｌ（Ⅲ）羟基配合物间的平衡配比。由此找出了ＰＡＦＣ溶液的碱化度Ｂ、总铁浓度〔Ｆｅ〕Ｔ与     

载Ni双功能碱性沸石催化剂的研究

采用分步浸渍法制备了负载Ni和KOH的NaX沸石催化剂 ,用XRD、TPR、CO2 TPD和XPS等手段对样品的结构、表面碱性、金属组分的可还原性、表面Ni物种的形态等进行了表征 ,对金属组分和碱性组分间的相互作用进行了研究 ,并揭示了这种作用的本质.同时结合丙酮一步法合成甲基异丁基酮的反应 ,探讨了反应性与样品碱性、金属性的关系 ,阐明了该反应中双功能催化剂上金属组分与碱性组分必须匹配合宜的原因     

The Hammett acidity function H0 in trifluoroacetic acid–dichloromethane mixtures

The acidity function (H₀) of solutions of trifluoroacetic acid (TFA) in dichloromethane was measured by the indicator method at 298 K in the whole concentration range. The H₀ value for the most acidic solution studied (12.93 M trifluoroacetic acid) is −3.09. The equation describing the dependence of H₀ on the acid concentration was determined. The obtained quantitative data were used for a spectrophotometric study of the basicity of 2,9,16,23-tetra-tert-butylphthalocyanine. Two forms with different UV/vis spectra were observed and their stability constants determined.     

La(OH)3和 La2O2CO3纳 米 棒 的 合 成 及 其 催 化 Claisen-Schmidt缩合反应性能简

通过调节溶液的pH值,在水热条件下合成出长径比为2-45的La（OH）₃纳米棒. 对水热合成过程中间体的结构演变分析,发现高碱度有利于小尺寸晶核的形成,La（OH）₃晶体结构的各向异性导致这些晶种沿着C轴方向生长,进而形成纳米棒结构. 将La（OH）₃纳米棒前驱体于773 K焙烧可以得到长径比为2-20的La₂O₂CO₃纳米棒. 随着长径比的增加,La₂O₂CO₃纳米棒暴露的（110）晶面逐渐增加,La³⁺-O^2-碱性位的数目也从0.08增加到0.24 mmol/g. 因此,在Claisen-Schmidt缩合反应中,La₂O₂CO₃纳米棒催化剂上的反应速率随着长径比的增加而逐渐增大.     

Hydrosoluble transition-metal coordination compounds of triphenylphosphine m-trisulfonate

By using ³¹P NMR and IR techniques it is established that the basicities of triphenylphosphine m-trisulfonate (TPPTS) and triphenylphosphine (PPh₃) are in the same order of magnitude. This highly hydrosoluble phosphine is a convenient ligand for the synthesis of hydrosoluble coordination compounds of molybdenum(0), palladium(II), platinum(II) and rhodium(I). The exchange of TPPTS with ligands other than PPh₃ (nitriles, carbon monoxide, olefins, chloride) can be used to obtain the desired complexes. However, because redox reactions between metal salts, water and TPPTS are possible, the synthesis of lowvalent precursors must be carried out and the experimental conditions have to be carefully controlled to avoid side-reactions and the participation of the sulfonate anions in competitive reactions.     

Proton Shuttling by Polyaniline of High Brønsted Basicity for Improved Electrocatalytic Ethylene Production from CO2

Hybrid organic/inorganic composites with the organic phase tailored to modulate local chemical environment at the Cu surface arise as an enchanting category of catalysts for electrocatalytic CO₂ reduction reaction (CO₂RR). A fundamental understanding on how the organics of different functionality, polarity, and hydrophobicity affect the reaction path is, however, still lacking to guide rational catalyst design. Herein, polypyrrole (PPy) and polyaniline (PANI) manifesting different Brønsted basicity are compared for their regulatory roles on the CO₂RR pathways regarding *CO coverage, proton source and interfacial polarity. Concerted efforts from in situ IR, Raman and operando modelling unveil that at the PPy/Cu interface with limited *CO coverage, hydridic *H produced by the Volmer step favors the carbon hydrogenation of *CO to form *CHO through a Tafel process; Whereas at the PANI/Cu interface with concentrated CO₂ and high *CO coverage, protonic H⁺ shuttled through the benzenoid -NH- protonates the oxygen of *CO, yielding *COH for asymmetric coupling with nearby *CO to form *OCCOH under favored energetics. As a result of the tailored chemical environment, the restructured PANI/Cu composite demonstrates a high partial current density of 0.41 A cm⁻² at a maximal Faraday efficiency of 67.5 % for ethylene production, ranking among states of the art.     

硼取代后氨化处理的分子筛碱性的理论研究

利用笼状的分子筛模型, 在B3LYP/6-311++G(d,p)水平下通过对分子筛中各种碱性基团的碱性进行对比来预测硼取代后氨化处理的分子筛的碱性. 结果表明, B-NH2基团本身碱性不强, 但与质子或路易斯酸作用时, B-NH2基团与周围的Si-OH基团共同参与作用并导致碱性增强. 另外, 分子筛中含有的Si-NH2基团也可与周围的B-OH共同作用, 产生强碱性. 因此, 硼取代后氨化处理的分子筛是一种优良的碱性材料.