Lijun Zhu

The effect of a hydrogen bond on the supramolecular self-aggregation mode and the extent of metal-free benzoxazole-substituted phthalocyanines

Two novel metal-free phthalocyanines have been designed and synthesized, namely tetra{[1H-benzo(d)imidazol-2-yl]thiol}phthalocyanine (TBIT-Pc) and tetra{[benzo(d)thiazol-2-yl]thiol}phthalocyanine (TBTT-Pc). These two compounds showed similar structures, while imidazolyl-NH in the substitutes of TBIT-Pc could form more hydrogen bonds. TBIT-Pc and TBTT-Pc were fully characterized by elemental analysis, 1H NMR, MALDI-TOF MS, FT-IR and the UV-Vis absorption spectrum. The self-assembly properties of TBIT-Pc and TBTT-Pc were comparatively studied. TBIT-Pc and TBTT-Pc were present as monomers in DMF in the concentration range of 9.04–20.3 μM. Depending mainly on the intermolecular hydrogen bonding (N–H⋯N) between benzimidazole substitutes, “head-to-tail” J-aggregates of TBIT-Pc were formed in DMSO, while there was no aggregation of TBTT-Pc in the same solvent. “Face-to-face” H-aggregates of TBIT-Pc and TBTT-Pc were formed with the addition of water to the solutions of DMSO, and the degree of aggregation increased with the introduction of H-bonds (N–H⋯N) in the benzimidazole substitutes of TBIT-Pc. The atomic force microscope (AFM) image and dynamic light scattering (DLS) displayed the formation of well-defined nanoparticles with a diameter of ca. 30 ± 15 nm with J-type aggregation of TBIT-Pc. And the dendritic nanostructures with H-aggregates of TBIT-Pc and TBTT-Pc with different size were observed from transmission electron microscopy (TEM) images. The possible mechanism of the effect of H-bonds on the formation of J-aggregates of TBIT-Pc and the H-aggregation of TBIT-Pc and TBTT-Pc was also discussed. In the formation process of aggregates, H-bonds and π–π interaction may be the dominant factors. In addition, the nanostructures fabricated from TBIT-Pc and TBTT-Pc showed good semiconducting properties revealed by current–voltage measurements.

Solid-phase synthesis and catalytic sweetening performance of sulfonated cobalt phthalocyanine from sulfonated phthalic anhydride mixture

A relatively green, efficient and economical synthetic route for the one-step solid-phase synthesis of sulfonated cobalt phthalocyanine from sulfonated phthalic anhydride mixture was studied, and could solve the serious problems of waste acid pollution and the low utilization of materials in the direct sulfonation of phthalocyanine. The optimal reaction conditions were using a phthalic anhydride mixture with a sulfonation degree of 60% as the raw material, a ratio of urea to PA–SPA mixture of 4 : 1, a ratio of cobalt chloride to PA–SPA mixture of 1 : 4, ammonium molybdate (1 wt%) as catalyst, and carrying out the reaction at 260 °C for 3 hours. Under these optimal conditions, a yield of 52.9% can be achieved. Through sweetening experimental studies, the synthesized sulfonated cobalt(II) phthalocyanine had better sweetening performance than the industrial catalysts, in both the liquid–liquid sweetening and fixed bed sweetening experiments. A sweetening rate of 93% can be achieved in 20 min with the synthesized catalyst in a fixed bed.

Structure and adsorptive desulfurization performance of the composite material MOF-5@AC

A composite material (MOF-5@AC) of MOF-5 and AC was successfully prepared. After characterization by a variety of means, it was shown that MOF-5 was covered on the surface of AC and existed in the form of microcrystals. A new micro-mesoporous pore appeared at 1.8–5 nm, while MOF-5 and AC are both microporous materials. And the thermal and water stability of MOF-5@AC is better than that of MOF-5. The adsorptive desulfurization experiment showed that the performance of the composite material was higher than that of the two parent materials, especially for the large molecular thiophenic sulfur compounds. And the reuse performance of MOF-5@AC after regeneration was also significantly improved compared the parent materials. The ratio of raw materials of composite materials plays an important role in the microstructure, morphology and desulfurization properties. After screening the ratio of raw materials, MOF-5@AC with a ratio of 1 : 5 showed the best desulfurization performance. The theoretical calculation results are in accordance with the desulfurization performance of the composite material (MOF-5@AC), which shows that MOF-5 is well dispersed on the AC surface and the pores are well exposed.

Synthesis and catalytic studies of novel tetra sulfonylphenoxyls substituted Co(II), Cu(II), and Ni(II) phthalocyanines for the LPG sweetening

ABSTRACT Novel tetrasubstituted Co(II), Cu(II) and Ni(II) phthalocyanines with 4-sulfonylphenoxyl groups were synthesized by reacting 4-(4-sulfonylphenoxy) phthalonitrile with metal chlorides. And their structures were characterized by UV-visible absorption, Fourier-transform infrared spectrum, 1H NMR, and MALDI-TOF MS. These novel phthalocyanine complexes showed excellent solubility in water and alkali solutions. By using sodium propanethiol as model compound, the catalytic activity of these phthalocyanine derivatives was investigated for improving the catalytic sweetening of liquefied petroleum gas. It was found that the performance of Co(II) phthalocyanine complex was the best among the synthesized Co(II), Cu(II), and Ni(II) phthalocyanines, and it was also better than the commercialized sweetening catalyst of disufonated cobalt phthalocyanine. Conversion of sodium propanethiol catalyzed by Co(II) phthalocyanine complex could reach 95.2% after 50 min reaction and the catalytic conversion was 92.8% after the solution of Co(II) phthalocyanine complex had been storage for 11 days.

Screening and Evaluation of Types and Ratio of Monomers of Oil Soluble Viscosity Reducing Agent for Shengli Super Heavy Oil

Based on the composition characteristics of the super heavy oil, nine kinds of oil-soluble viscosity reducing agents were synthesized. By adjusting the types and the ratio of monomer, the molecule structure was carefully screened out suitable for super heavy oil. The polymer from octadecyl acrylate and styrene got the best performance and had good temperature resistance. After treatment with agent, the viscosity is greatly reduced, and heavy oil becomes full Newtonian fluid, which is very convenient for storage and transportation. Polymer has two roles in the viscosity reduction process: infiltration effect of branched and supporting role from polymer backbone.

Molecular recognition with cyclodextrin polymer: a novel method for removing sulfides efficiently

A series of cyclodextrin polymers (CDPs) were synthesized and they were used for removing different sulfides by molecular recognition. Different CDPs showed a higher desulfurization efficiency for sulfides with an aromatic ring structure than those with an aliphatic chain structure. For different cyclodextrin polymers, β-CDP has a more suitable cavity size for removing DBT. Moreover, it has a good synergetic effect of adjacent cyclodextrin cavities and good electronic interactions with DBT. For these reasons, β-CDP showed the best desulfurization performance, in particular it has good performance for deep desulfurization by forming inclusion complexes and excellent selectivity for removing DBT. Meanwhile, the β-CDP showed good regeneration performance. Various characterization measurements were used to characterize the β-CDP before and after desulfurization of DBT, the results of which showed that it had advantages of wide application temperature range and good structure stability before and after desulfurization. Finally, a molecular recognition mechanism for removing sulfides efficiently was proposed.

Selective functionalization of external and internal surface of MCM-41 for adsorptive desulfurization

MCM-41 was selectively functionalized with CuO on the external surface and Cu2+ coordinated by organosilanes on the internal surface. The production of CuO and removal of template were achieved in one step, which is convenient and a save of energy. Results of transmission electron microscopy indicate the presence of CuO on outer surface of MCM-41. The successful grafting of organosilanes was confirmed by 13C and 29Si nuclear magnetic resonance. The prepared M(CuO)N(Cu) shows more comprehensive desulfurization performance due to the simultaneous and independent incorporation of CuO and copper ions. Dimethyl sulfide and dimethyl disulfide are selectively adsorbed on external surface of M(CuO)N(Cu), while tert-butyl mercaptan can be adsorbed on both external and internal surface of M(CuO)N(Cu).

Self-assembled core–shell nanospheres and dendritic nanostructure of novel tetra-(3-phenyprop-2-allyloxy) phthalocyanine in different solvents

Novel metal-free tetra-(3-phenyprop-2-allyloxy) phthalocyanine (TPAO-Pc) was synthesized and characterized by nuclear magnetic resonance spectrum (1H NMR), MALDI-TOF MS, Fourier-transform infrared (FT-IR) and UV-Visible absorption (UV-Vis) spectra. The effects of concentrations and solvents on the properties of self-assembly were investigated via absorption and fluorescence spectra, transmission electron microscopy (TEM). TPAO-Pc was stable in most organic solvents, such as toluene, acetone and dimethylsulfoxide (DMSO). However, the TPAO-Pc exhibited the tendency of forming “face-to-face” stacking mode self-assemblies (H-aggregate) in DMSO–water and acetone–water mixed solutions. Self-assembly of the TPAO-Pc was also demonstrated by fluorescence spectra. The TEM images displayed the core–shell nanospheres and dendritic nanostructure of TPAO-Pc formed in the DMSO–water and acetone–water mixed solutions, respectively. The mechanism of the self-assemblies growth was proposed on the basis of the experimental results. The morphology of the TPAO-Pc self-assemblies was related with the selected solvent conditions and the aggregation time. H-bond, π–π interaction may be the main driving force for the formation of core–shell nanospheres and dendritic nanostructure.

Microwave-Promoted Synthesis of Sulfonated Metallophthalocyanines and Aggregation in Different Solvents

Five metallosulfophthalocyanines (Fe, Ni, Zn, Co, and Cu) compounds were synthesized by microwave irradiation. Compared to the conventional method of synthesis in terms of reaction time and yields, the microwave-promoted synthesis is preferred with high product yield and short reaction time. All synthesized products were characterized with MALDI-TOF mass spectrum, Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), and X-ray diffraction (XRD). Aggregation behavior of the five metallosulfophthalocyanines (MSPc) in different solvents was studied by UV-Vis spectroscopy separately in N,N-dimethyl formamide (DMF) and NaOH aqueous solution (5%wt). A redshift of maximum absorption wavelength and deviations from Lambert-Beer law with increasing the concentration were observed. The dimerization equilibrium constants (K) of the five MSPc were determined, respectively.

New Determination Method for Sulfonation Degree of Phthalic Anhydride by RP-HPLC

A novel method was developed to monitor the reaction process and evaluate the sulfonation level in the sulfonation of phthalic anhydride by reversed-phase high-performance liquid chromatography (RP-HPLC). The product peak was identified in chromatograms through product analysis and by comparing its retention time with that of standard compounds. By comparing the hydrolysis and alcoholysis methods, optimized pretreatment of the sample was found for RP-HPLC. Based on the determined percentages of phthalic anhydride and sulfonated phthalic anhydride in the mixture, the degree of sulfonation was calculated. When the sulfonation degree of phthalic anhydride was in the range of 2.8-71%, the recovery of 97-104% was achieved, and the procedure was rapid and accurate.