POLYMERIZATION MECHANISM OF N-VINYLCARBAZOLE WITH CHIRALLY ORGANIC SALT AS CATALYST

The polymerization mechanism is described by the conductance changewith the time during the polymerization. The mechanism can be explained by the equi-librium feature (i.e. main ion-pairs) between the free ions and the ion-pairs dissociated bythe organic salt (-) Sp~/(*~+) (+) CSA~(*~-) (An asterisk represents the chirality) and the schemeof the polymerization process is described mainly by the charge transfer complexes havingchiral induction power.     

EPOXIDATION OF OLEFINS WITH IODOSYLBENZENE CATALYZED BY POLYMER－SUPPORTED MANGANESE PORPHYRINS

ＥＰＯＸＩＤＡＴＩＯＮＯＦＯＬＥＦＩＮＳＷＩＴＨＩＯＤＯＳＹＬＢＥＮＺＥＮＥＣＡＴＡＬＹＺＥＤＢＹＰＯＬＹＭＥＲ－ＳＵＰＰＯＲＴＥＤＭＡＮＧＡＮＥＳＥＰＯＲＰＨＹＲＩＮＳ￥ＪｉｎｇＳｏｎｇＹＯＵ，ＸｉａｏＱｉＹＵ；ＹｏｕＦａＸＩＡＯ；ＹｉＬｉａｎｇＷ...     

COMBINATORIAL SYNTHESIS OF MANNICH BASES IN SOLUTION／POLYMER REAGENT WORKUP

This paper describes a combinatorial synthesis the mannich bases in Solution through the Mannich reaction using 3 ketones,5 amines and formaldehyde in solution and hydrochloride as a catalyst and then using a macroporous quarterized ammonium resin(CO32-form)as a scavenge agent to remove the acid catalyst when the Mannich reaction is completed.It was found by GC/MS analysis that the symmetrical ketone,such as acetone,in the Mannich reaction mainly produces one Mannich base;while the asymmetrical ketone,such as 2-pentanone,gives two.     

ZEOLITE－CATALYZED FRIEDEL－CRAFTS ACYLATION OF AROMATICS∶Ⅲ．SYNTHESIS OF 4－ACYL ANISOLE WITH USY CATALYST

ＺＥＯＬＩＴＥ－ＣＡＴＡＬＹＺＥＤＦＲＩＥＤＥＬ－ＣＲＡＦＴＳＡＣＹＬＡＴＩＯＮＯＦＡＲＯＭＡＴＩＣＳ：Ⅲ．ＳＹＮＴＨＥＳＩＳＯＦ４－ＡＣＹＬＡＮＩＳＯＬＥＷＩＴＨＵＳＹＣＡＴＡＬＹＳＴ￥ＹｕＤａｏＭＡ；ＱｉＬｏｎｇＷＡＮＧ；ＸｉｎｇＤｏｎｇＪＩ；Ｃ...     

INVESTIGATION ON THE INTERACTION OF METHANE WITH MgO SURFACE BY FT－IR SPECTROSCOPY

ＩＮＶＥＳＴＩＧＡＴＩＯＮ　ＯＮ　ＴＨＥ　ＩＮＴＥＲＡＣＴＩＯＮ　ＯＦ　ＭＥＴＨＡＮＥ　ＷＩＴＨ　ＭｇＯ　ＳＵＲＦＡＣＥ　ＢＹ　ＦＴ－ＩＲ　ＳＰＥＣＴＲＯＳＣＯＰＹＣｈｅｎ，Ｌａｉ－ｙｕａｎ；Ｌｉｎ，Ｌｉ－ｗｕ；Ｘｉｎ，Ｑｉｎ；Ｙｉｎｇ，Ｐｉｎ－ｌｉ...     

STUDIES ON THE INTERACTION OF EPOXY POLYMERS WITH HOMOPOLYUREAS

INTRODUCTION Epoxy resins are reactive polymers which when cured with a variety of chemicals lead to a host of useful thermosets. Since the epoxide is a strained ring, it readily undergoes addition and homopolymerization. The homopolymerization is a process catalysed by acids, bases, Lewis acids, t-amines as well as by inorganic salts.     

ZEOLITE－CATALYZED FRIEDEL－CRAFTS ACYLATION OF AROMATICS：I》．SYNTHESIS OF 4－ACYL ANISOLE WITH A HY CATALYST

ＺＥＯＬＩＴＥ－ＣＡＴＡＬＹＺＥＤＦＲＩＥＤＥＬ－ＣＲＡＦＴＳＡＣＹＬＡＴＩＯＮＯＦＡＲＯＭＡＴＩＣＳ：Ｉ．ＳＹＮＴＨＥＳＩＳＯＦ４－ＡＣＹＬＡＮＩＳＯＬＥＷＩＴＨＡＨＹＣＡＴＡＬＹＳＴ￥ＱｉＬｏｎｇＷＡＮＧ；ＹｕＤａｏＭＡ；ＸｉｎｇＤｏｎｇＪＩ；Ｈ...     

STUDIES ON THE KINETICS OF PROPYLENE POLYMERIZATION WITH THE COMPLEXTYPE TiCl_3 CATALYST

The active center concentration C_p, the rate constant k_p, and the activation energy of chain propagation E_p in the polymerization of propylene with complex-type TiCl_3-(C_2H_5)_2AlCl catalyst system were studied. The Mn was corrected by (?) value determined by GPC. The values thus obtained for C_p, k_p, and E_p at 50℃were 3.01 mol/mol Ti, 6.27 1/mol·sec, and 5.10 Kcal/mol respectively.The kinetic parameters were compared with those obtained from conventional TiCl_3·AlCl_2 catalyst, showing that the higher activity of the complex-type catalyst over the conventional catalyst is not only due to the higher C_p of the former, but to a greater extent due to the increase of the k_p value.     

COMPATIBILITY OF PVC WITH POLYURETHANES OF DIFFERENT SOFT SEGMENTS

Blends of PVC and polyurethanes with four different soft segments of molecular weight 1000 were prepared and studied by dynamic mechanical and DSC techniques. It was found that the compatibility of PVC with segmented polyurethanes was related to the mixing of PVC molecules and the soft segments of the polyurethanes. Polyester based polyurethanes are more compatible with PVC than polyether based polyurethanes. Solution cast blends of PVC with PCL-polyurethane (1/2/1) exhibit single and narrow glass transition, while the blends with PPO-polyurethane (1/2/1) are completely incompatible. The compatibility was found to decrease with increasing hard segment content for all the polyurethanes used. The methods of blend preparation may change the compatibility of PVC/PU blends through their influence on the mixing or demixing of the hard and soft segments.     

INTERACTION MECHANISM OF AMPHOTERIC COLLECTOR-I WITH METALLIC IONS AND MINERALS

The electronic structure and bonding nature of adsorbing bonding complexes which consist of Amphoteric Collector-I and Mg~(2+), Ca~(2+), MgPO_4~-, CaPO_~-4, CaCO_3, as well aa MgCO_3, are studied using quantum chemistry CNDO/2, It is predicted that magnesium salts are more liable to form adsorbing chelates with Amphoteric Collector-I than calcium salts, and all results coincide with that obtained in flotation.     

STUDIES OF THE INTERACTION BETWEEN METALLOPORPHYRINS OF TMPYP－3 AND SINGLE－STRANDED DNA ON NC MEMBRANE

ＳＴＵＤＩＥＳＯＦＴＨＥＩＮＴＥＲＡＣＴＩＯＮＢＥＴＷＥＥＮＭＥＴＡＬＬＯＰＯＲＰＨＹＲＩＮＳＯＦＴＭＰＹＰ－３ＡＮＤＳＩＮＧＬＥ－ＳＴＲＡＮＤＥＤＤＮＡＯＮＮＣＭＥＭＢＲＡＮＥ￥ＹｏｎｇＣＨＥＮ；ＹｕａｎＺｏｎｇＬＩ；ＷｅｎＢａｏＣＨＡＮＧａｎｄＹ...     

STEREOSPECIFIC POLYMERIZATION OF STYRENE WITH MODIFIED TiCl_4/MgCl_2-AlEt_3 CATALYST

ｔｈａｓｂｅｅｎｒｅｐｏｒｔｅｄｉｎｔｈｅｌｉｔｅｒａｔｕｒｅｔｈａｔａｔａｃｔｉｃ，ｉｓｏｔａｃｔｉｃａｎｄｓｙｎｄｉｏｔａｃｔｉｃｐｏｌｙｓｔｙｒｅｎｅｃａｎｂｅｏｂｔａｉｎｅｄｂｙｕｓｉｎｇｄｉｆｅｒｅｎｔｃａｔａｌｙｓｔｓｙｓｔｅｍｓ［１～５...     

ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYZED BY METALLOPORPHYRINS(Ⅱ)——ELECTROSYNTHESIS OF SOME ORGANIC COMPOUNDS WITH CO_2 CATALYZED BY CoTPP

The catalyzation of CoTPP for electrocarboxylation of alkyl halides, alkenes and ketones with CO_2 are studied. The electrocarboxylation of these organic compounds with CO_2 in the presenec of catalyst can occur at more positive potential than that of no catalyst. The products of electrocarboxylation were identified by UV, IR and GC-MS. The electrocarboxylation mechanisms of different organic compounds are discussed.     

STUDY ON PREPARATION AND CATALYTIC ACTIVITY OF A NEW POLYMER LEWIS ACID CATALYST

This paper reports the study on the polymer protected catalyst CPVC-FeCl3 used in esterification, transesterification, synthesis of acetals or ketals and rearrangement reaction of pinacol.The catalyst has the advantages of being simple in operation, non-corrosive, easy to separate from mixtures and good reusability.     

DETERMINATION OF PHOSPHORUS AND FLUORINE IN POLYMERS AND ORGANIC COMPOUNDS WITH Nd~(3+)

Percentages of P or/and F in polymers and organic compounds are found by using Nd~(3+) as pre-cipitant and subsequent titration of excess Nd~(3+) with EDTA after decomposing sample in oxygenflask. The errors of determination are for P<±0.20% and F<±0.30% except fully fluorinatedcompounds.     

MICELLIZATION STUDIES OF DODECYL BENZENESULFONIC ACID AND ITS INTERACTION WITH POLYVINYLPYRROLIDONE

Dodecyl benzenesulfonic acid (DBSA) surfactant was used in the present study to find the effect of concentration on its electrical conductance in solution from 293-323K above and below the critical micelle concentration (CMC). The micellization parameters i.e. degree of counter ion binding (β), aggregation number (n) and number of counter ion micelle(m) were measured. The interaction of DBSA with polyvinylpyrrolidone (PVP) was also studied at 293K throughconductance and surface tension measure ments. A number of important parameters i.e. critical aggregation concentration (CAC), Gibb‘s free energy (△G) and binding ratio (R) were determined and the effect of NaCl on the CAC and polymer saturation point (PSP) was also investigated.     

NMR STUDIES ON THE WEAK INTERACTION OF FOUR-MONONUCLEOTIDES WITH TRYPTAMIDE AND LEUCINAMIDE

NMR spectroscopy analysis was introduced to investigate the weak interaction of four 5'—mononucleotides with tryptamide and leucinamide. Assuming a 1∶1 complex formation, the association constants were determined by nonlinear regression analysis. The association affinity of 4 mononucleotides with tryptamide decreased in the order: G>A>C>U, indicating that purine bases stack more strongly with tryptamide than pyrimidine bases. But with leucinamide the affinity decreases in the order: G>C>A=U, suggesting an amino acid—anticodonic preferential interaction. The implication of the present data to the origin of genetic code was briefly discussed.     

PREPARATION OF POLYMER MICROSPHERES WITH PYRIDYL GROUP AND THEIR STABILIZED GOLD METALLIC COLLOIDS

Narrow disperse poly(ethyleneglycol dimethacrylate-co-4-vinylpyridine)(poly(EGDMA-co-4-VPy))microspheres were prepared by distillation-precipitation copolymerization of ethyleneglycol dimethacrylate(EGDMA)and 4-vinylpyridine (4-VPy)with 2,2'-azobisisobutyronitrile(AIBN)as initiator in neat acetonitrile.The polymer microspheres containing pyridyl group were then utilized as stabilizer for gold metallic colloids with the diameter around 7 nm,which were prepared by the in situ reduction of gold chloride trihydrate with sodium borohydride through the coordination of the pyridyl group on the gel layer and surface of the microsphere with the gold metallic nano-particles.The catalytic properties of the pyridyl- functionalized microsphere-stabilized gold metallic colloids and the behavior of the stabilized-catalyst for the recycling were investigated with reduction of 4-nitrophenol to 4-aminophenol as a model reaction.     

NUCLEAR MAGNETIC RESONANCE STUDIES OF THE INTERACTION OF Ca~(2+) WITH SIALIC ACID~*

The interaction of Ca~(2+) with sialic acid has been investigated by 500 MHz proton nuclear magnetic resonance spectroscopy. The changes of chemical shifts were observed for all sialic acid protons at different Ca~(2+) concentrations, and these spectral observations were also accompanied by changes in the J-coupling constants between the H_7 and H_8 protons and between the H_8 and H'_9 potens. Analysis of these Ca~(2+)-induced changes indicated that three oxygen atoms among (OH)_7, (OH)_8 and (OH)_9 of sialie acid formed a geometrical space suitable for Ca~(2+) coordination As a consequence, sialic acid provided a high-affinity binding site for Ca~(2+), the binding constant was about 104.72m~(-1).     

PREPARATION OF HIGHLY BRANCHED POLYETHYLENE WITH ACENAPHTHENEDIIMINE NICKEL CHLORIDE/DIETHYLALUMINUM CHLORIDE CATALYST

The homogeneous catalyst system [ArN = C(Nap)- C(Nap)= Nar]NiCl2 (Nap = 1,8-naphthdiyl, Ar = 2,6-diisopropylphenyl)/AlEt2Cl has been prepared and examined for ethylene polymerization. Polymerization conditions such as cocatalyst, Al/Ni molar ratio and polymerization temperature (Tp) have a great effect on catalytic activity and properties of polyethylenes (PE). The activity of 5.1 × 105g PE/mol Ni. H was obtained by the catalyst, activated with AlEt2Cl at 120 of Al/Ni ratio and 30℃. Especially, Tp had a pronounced influence on branches and molecular weight of PE. Branching degree of PE increased with increasing temperature whereas their molecular weight decreased correspondingly. At Tp lower than about 70℃, the resultant PE was an elastic material. When Tp was higher than 70℃, the product was a viscous oil. The resultant PE was confirmed by 13C-NMR to contain significant amounts of not only methyl but also ethyl, propyl, butyl,amyl, and longer branches (longer than six carbons). According to gel permeation chromatographic measurement, the weightaverage molecular weights of the polymers obtained ranged from 3.6 × 103 to 2.3 × 105.