Mixed Chlorometallate Ionic Liquids as C4 Alkylation Catalysts: A Quantitative Study of Acceptor Properties

The acceptor properties of mixed chlorometallate ionic liquids for isobutane-butene alkylation (C4 alkylation) reaction were studied. These ionic liquids were prepared by mixing metal chlorides with either triethylamine hydrochloride or 1-butyl-3-methylimidazolium chloride in various molar ratios. Using triethylphosphine oxide as a probe, Gutmann Acceptor Numbers (AN) of the catalysts were determined, and the Lewis acidity of mixed chlorometallate ionic liquids was quantitatively measured. Additionally, AN value was developed to determine the relationship between Lewis acidity and catalytic selectivity. The favorite AN value for the C4 alkylation reaction should be around 93.0. The [(C2H5)3NH]Cl–AlCl3−CuCl appears to be more Lewis acidity than that of [(C2H5)3NH]Cl–AlCl3. The correlation of the acceptor numbers to speciation of the mixed chlorometallate ionic liquids has also been investigated. [AlCl4]−, [Al2Cl7]−, and [MAlCl5]− (M = Cu, Ag) are the main anionic species of the mixed chlorometallate ILs. While the presence of [(C2H5)3N·M]+ cation always decreases the acidity of the [(C2H5)3NH]Cl−AlCl3−MCl ionic liquids.

Determination of the surface properties of kaolinite by inverse gas chromatography

Inverse gas chromatography (IGC) was applied to characterize the surface of kaolinite. The adsorption thermodynamic parameters (the standard enthalpy (∆H0), entropy (∆S0) and free energy of adsorption (∆G0), the dispersive component of the surface energy (γsd), and the acid/base character of kaolinite surface were estimated by using the retention time of different non-polar and polar probes at infinite dilution region. The specific free energy of adsorption (∆Gsp), the specific enthalpy of adsorption (∆Hsp), and the specific entropy of adsorption (∆Ssp) of polar probes on kaolinite were determined. (∆Gsp) values were correlated with the donor and modified acceptor numbers of the probes to quantify the acidic (KA) and the basic (KD) parameters of the kaolinite surface. The values obtained for the parameters KA and KD indicated a basic character for kaolinite surface.

Phosphorescent platinum(ii) alkynyls end-capped with benzothiazole units

Phosphorescent platinum(ii) alkynyls. Phosphorescent trans-bis(alkynyl) bis(phosphine) or bis(cyanide) PtII derivatives (1–4) based on the 2-phenylbenzothiazole unit have been prepared. The negative solvatochromic behavior of 4 has been analyzed by the Kamlet–Taft solvent scale and the Gutmann's acceptor numbers. The optical properties were addressed by TD and DFT calculations on 2 and 4.

Analysis of structures with saturated hydrogen bonding

All simple structures with saturated hydrogen bonding (SHB) are classified into eight categories on the basis of the donor and acceptor numbers on the atoms at each end of the hydrogen bonds. Examples from the literature are included where known, along with seven structures investigated as part of this study (five have SHB). Graph-set descriptions of the hydrogen-bond patterns are given for each of these structures and for some selected literature examples. The structures presented are: piperazine (I), morpholinium chloride (II) and iodide (III) [(II) and (III) are not SHB], three 1:1 cocrystals of diols with 1,4-phenylenediamine (PDA) – PDA·1,8-octane diol (IV), PDA·1,10-decane diol (V), and PDA·1,12-dodecane diol (VI) and 6-amino-1-hexanol (VII). This study discusses some structures that show limitations of the graph-set model, along with possible suggestions to cover these limitations. The cocrystalline PDA·aliphatic diol structures may provide details applicable to the structure of self-assembled monolayers of aliphatic thiol molecules on Au(111) surfaces.