Synthesis of 1-benzoylpyrene using silica-supported phosphotungstic heteropoly acid as an efficient and reusable catalyst

A novel one-pot catalytic synthesis of 1-benzoylpyrene through acylation of pyrene with benzoic anhydride catalyzed by several heteropoly acids (HPAs) was investigated. Pure 1-benzoylpyrene was obtained and its structure was identified by GC/MS, FT-IR and ¹H NMR spectra. Silica-supported phosphotungstic heteropoly acid (PW/SiO₂) was found to be the most active catalyst in the acylation. The yield and the selectivity of 1-benzoylpyrene were up to 62.5% and 100%, respectively. The effects of experimental parameters on the catalytic acylation reaction, and the possibility of reusability of PW/SiO₂ catalyst were studied. PW/SiO₂ catalyst is easily separable from the reaction mixture and reusable without loss of its activity.     

Study on the relationship between the structure and activities of alkyl methacrylate–maleic anhydride polymers as cold flow improvers in diesel fuels

In order to find efficient cold flow improvers for diesel fuels derived from crude oil, copolymers (R¹MC–MA) were prepared making use of the copolymerization of methacrylate (R¹MC) of various alkyls with maleic anhydride (MA), and terpolymers (R¹MC–MA–R²MC) were prepared by the reaction of long-chain alkyl methacrylate (R¹MC), maleic anhydride (MA), and short alkyl methacrylate (R²MC). The additives were purified and characterized by IR, ¹H–NMR, and GPC. The activities of the synthetic products as the cold flow improvers in two diesel fuels were investigated. The results indicate that: (1) the alkyl chain length of R¹ in R¹MC–MA copolymers significantly affects the solid point depressing performance. When the long-chain alkyl R¹ is n–C₁₄H₂₉– and the reaction material molar ratio (R¹MC/MA) is 1:2, the C₁₄MC–2MA possesses the best ΔSP property; (2) the (C₁₄MC–MA–R²MC) terpolymers all demonstrate excellent solid point depression properties when the short-chain alkyl R² varies from CH₃– to n–C₈H₁₇–; (3) however, all of the tested copolymers and terpolymers do not demonstrate necessary cold filter plugging point depression performance.     

Characterization and dual functionalization of polystyrene with propionic anhydride and cyanate derivatives

First, Friedel–Crafts reactions were used for the acylation process. For this, polystyrene (PS) was reacted with propionic anhydride in the presence of Lewis acid catalyst. The amount of acyl group linked PS as a result of acylation has been identified as volumetric. Second, the bromination and lithiation reactions of acylated PS containing carbonyl groups were realized. Also, the lithiated PS containing acyl groups has been modified a second time with various isocyanates and isothiocyanate derivatives in the presence of n?BuLi catalyst. Some important reaction parameters were assigned in order to optimize the process. The structure all of the products were characterized by Fourier transform infrared, ¹H NMR (Proton Nuclear Magnetic Resonance), and thermogravimetric methods. In addition, reaction yields were determined according to the result of elemental analysis. Dual functionalization yields were realized between 62.2% and 69.9%. For kinetic analysis, the TG/DTG (Thermal Gravimetric Analysis/Differantial Thermal Analysis) data obtained at three different heating rates were processed by Kissinger–Akahira–Sunose method. The results demonstrated that the acylation reaction, bromination and lithiation reactions, and dual functionalization reactions with cyanate derivatives can be carried out to obtain a significantly functionalized polymer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1351‐1362, 2013     

Effect of the maleic anhydride content on the structural,thermal, rheological and film properties of the n-butyl methacrylate–maleic anhydride copolymers

Various copolymers of n-butyl methacrylate (nBMA)-maleic anhydride (MA) were synthesized by free radical solution polymerization using xylene as a solvent, with monomer ratio of (nBMA/MA) 80/20, 65/35 and 50/50 wt%. The nBMA/MA copolymers were analyzed by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC) differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), rheology, acid value, microhardness and friction resistance. The formation of the nBMA/MA copolymers was proven by FTIR and ¹H NMR. The conversion percentage, glass transition temperature (T_g), thermal stability, hardness and the friction resistance of the nBMA/MA copolymers increased with the MA contents in the copolymers. All copolymers presented a thinning-shear rheological behavior due to the presence of entanglements. All films of the copolymers showed a good chemical resistance to HCl and NaCl solutions, but in the presence of NaOH solutions the films exhibited a blister.     

Complex-radical copolymerization of <Emphasis Type="Italic">N-</Emphasis>vinyl pyrrolidone with isostructural analogs of maleic anhydride

Radical copolymerizations of N-vinyl-2-pyrrolidone (VP) with isostructural analogs of maleic anhydride (MA), such as citraconic anhydride (CA) and N-substituted maleimides [maleimide (MI), N-ethylmaleimide (EMI) and N-phenylmaleimide (PhMI)] were studied. Compositions of copolymers synthesized in a wide range of monomer feed ratios were determined by alkali titration (for anhydride copolymers), FTIR and ¹H NMR spectroscopy using 1495 and 630 cm^-1 (for VP-MI), 1289 and 1225 cm^-1 (for VP-EMI) and 1050 and 3067 cm^-1 (for VP-PhMI) analytical bands and integral areas of CH₂ (pyrrolidone ring) and CH (MI), CH₃ (EMI) and CH= (benzene ring in PhMI) groups, respectively. Electron-donor VP monomer was found to have substantially different reactivities in the radical copolymerization with MA, CA and N-substituted (H, C₂H₅ and phenyl) malemides as electron-acceptor comonomers. Effects of H-bonding and N→O=C coordination on the monomer reactivity ratios were evaluated. Tendency to alternation of the monomer pairs increases in the order of VP–MA > VP–CA > VP-MI > VP-PhMI > VP-EMI. Structure-thermal property-relationship for the synthesized copolymers was also studied.     

Enzyme-catalyzed polymerization and degradation of copolyesters of ε-caprolactone and γ-butyrolactone

Copolymers of γ-butyrolactone (γ-BL) and ε-caprolactone (ε-CL) were successfully synthesized by ring-opening polymerization using Novozyme-435 (immobilized lipase B from Candida antartica) as catalyst. Copolymers with different compositions were obtained and characterized by ¹H NMR, ¹³C NMR, GPC, DSC and X-ray diffraction. Increasing the [BL]/[CL] feed ratio resulted in decreases of molecular weight (M_n) of copolymers and reaction yield. Moreover, the BL contents in the copolymers varied according to the feed ratio. The T_m of the copolymers decreased from 58 to 49 °C with increase in BL content from 0 to 14%. The resulting copolymers were all semicrystalline with a PCL-type crystalline structure. Solution cast films were allowed to degrade in a pH 7.0 phosphate buffer solution containing Pseudomonas lipase. Weight loss data showed that the degradation rate of copolymers in the presence of Pseudomonas lipase decreased with the increase of BL contents.     

Monomer sequence of partially hydrolyzed poly(4-tert-butoxystyrene) and morphology of diblock copolymers composing this polymer sequence as one block

The molecular characteristics of poly(4-tert-butoxystyrene) (O) upon hydrolysis reaction were investigated. It is known that O can be converted into poly(4-hydroxystyrene) (H) through hydrolysis reaction using strong acid. In this study, a set of poly(4-tert-butoxystyrene-co-4-hydroxystyrene)s (O/H copolymers) having various conversion rates, f_Hs, were prepared. Hydrolysis reaction is found to occur uniformly by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) where the average f_H obtained was consistent with that from ¹H NMR though a certain distribution in the number of hydrolyzed units was conceived. Monomer sequence of O/H copolymers was determined by ¹³C NMR and the changes in triad concentration were obtained by spectra subtraction method. As a result, ¹³C NMR reveals that O and H are statistically distributed. To evaluate the effect of hydrolysis on microphase-separated structure, we observed the morphology of partially hydrolyzed poly(4-tert-butylstyrene-block-4-tert-butoxystyrene) (BO) by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). Samples with f_H from 0.21 to 0.67 form both lamellar (major component) and cylindrical (minor component) structures reflecting both the statistical manner of hydrolysis reaction and the possible localized distribution of H sequence.     

Synthesis and characterization of poly(amideimide)s from 4-(p-carboxyphenoxy)phthalic anhydride and 4-(p-carboxybenzoyl)phthalic anhydride

A series of poly(amideimide)s were prepared by the reaction of two new anhydride acidchloride monomers with aromatic diamines. 4-(p-Carboxyphenoxy)phthalic anhydride was synthesized by nucleophilic displacement reaction of N-methyl-4-nitrophthalimide with p-hydroxybenzoic acid, followed by hydrolysis. The tricarboxylic acid was converted to the corresponding anhydride acidchloride. 4-(p-Carboxybenzoyl)phthalic anhydride was synthesized by Friedel–Craft's acylation of toluene with N-phenylphthalimide-4-carbonylchloride, which was then converted to anhydride acidchloride of 4-(p-carboxybenzoyl)phthalic acid. The monomers were characterized by IR and NMR. Several PAI were prepared by the reaction of these anhydride acidchloride monomers with aromatic diamines. The inherent viscosities of the polymers were in the range of 0.42–0.58 dL/g. All polymers were soluble in polar aprotic solvents. The polymers showed good thermal stability and T_g values were in the range of 226–269 °C. X-Ray diffractograms of polymers indicate amorphous nature of these polymers.     

High molecular weight graft stabilisers for dispersion polymerisation of vinylidene fluoride in supercritical carbon dioxide: the effect of architecture

A group of high molecular weight graft stabilisers, both fluorinated and non-fluorinated, were synthesised by thermal ring-opening esterification of anhydride copolymers. These included poly(methyl vinyl ether-alt-maleic anhydride) and poly(maleic anhydride-octadecene) and were reacted with alcohols, including 1H,1H,2H,2H-perfluorooctanol, 1H,1H,2H,2H-perfluoro-dodecanol and 1-octanol. The stabilisers were fully characterised by ¹H, ¹⁹F and ¹³C nuclear magnetic resonance, diffuse reflectance Fourier transform infrared spectroscopy, and thermal analysis. Their phase behaviour in supercritical carbon dioxide (scCO₂), vinylidene fluoride (VDF), and a mixture of scCO₂/VDF was also studied using a variable volume view cell. Each stabiliser was tested for the dispersion polymerisation of VDF in scCO₂. The effect of the stabiliser architecture on the molecular weight and morphology of the poly(vinylidene fluoride) (PVDF) polymer product was investigated. Steric stabilisation effects were observed. Gel permeation chromatography and scanning electron microscopy were used for the characterisation of the molecular weight and morphology of PVDF polymers.     

Synthesis and Polymerization of Epoxy Methacrylates, 2. Acylated Epoxy Methacrylates and their Copolymers

Partially (20–75%) acylated isopropylidene‐bis[1,4‐phenyleneoxy(2‐hydroxytrimethylene)] dimethacrylate (BisGMA) was prepared by a single step reaction of 2,2‐bis[4‐(2,3‐epoxypropoxy)phenyl]propane (DGEBA) with methacrylic acid (MAA), methacrylic anhydride (MAAn) and/or acetic anhydride catalyzed by 0.8 mol‐% N‐methylimidazole at 90–100°C. In any case, MAA was substituted by an equimolar quantity of the anhydride. The reaction kinetics of DGEBA with MAA and MAAn follows a first order law up to a conversion of epoxy groups corresponding to the initial molar ratio of MAAn. For different mole fractions x_MAA, the reaction rate was found to be directly proportional to x^0.5_MAA. The viscosity of BisGMA decreased with an increase in the acylation degree. Acylated BisGMA was copolymerized with triethylene glycol dimethacrylate (TEGMA) by use of a redox initiator system at room temperature and with vinyltoluene (VT) initiated by di‐tert‐butyl peroxide at 150–200°C, respectively, both in the presence of 70–76 wt.‐% of quartz filler. Different dependencies of the content of sol and the conversion of C=C double bonds were observed for thermally polymerized composites from VT with acetylated and methacrylated BisGMA, respectively. Methacrylated BisGMA yielded composites with reduced water uptake. The higher network density of the polymer matrix with methacrylated BisGMA resulted in a higher glass transition temperature T_g and a higher storage modulus of the composites. The initial temperature of weight loss of composites with VT was increased from 230°C for composites with BisGMA up to 258°C for composites with BisGMA methacrylated to a degree of 40%.     

纤维素在离子液体中均相酰化反应动力学

以离子液体1-烯丙基-3-甲基咪唑氯盐（AmimCl）为反应媒介,以微晶纤维素为原料,研究了离子液体中纤维素与酸酐均相酰化反应的动力学,通过实验考察了纤维素初始羟基浓度（0.21～0.85 mol·L^-1）及反应温度（353～373 K）对酰化反应速率的影响。结果表明,随着离子液体中纤维素羟基浓度的增大和反应温度的升高,纤维素酰化反应的速率都呈增大趋势。通过实验得到了纤维素均相酰化反应的动力学方程,纤维素乙酐酰化及乙酐、丁酐混合酸酐酰化反应的反应级数均为1,表观活化能分别为19.03 kJ·mol^-1和20.04 kJ·相似文献   

Ionic Liquids Promoted the C-Acylation of Acetals in Solvent-free Conditions

The synthesis of a series of fourteen 4-alkoxy-1,1,1-trihalo-3-alken-2-ones (2,3) [CX₃COC(R²)=C(R¹)OMe, where X = Cl, F; R¹/R² = Me/H, Bu/H, i-Bu/H, Ph/H, Thien-2-yl/H, –(CH₂)₄–, –CH(CH₂)₄CH(CH₂)₂–] from the acylation reactions of acetals (1) with trichloroacetyl chloride or trifluoroacetic anhydride in the presence of equimolar amounts of pyridine and imidazolium based ionic liquid ([BMIM][BF₄] or [BMIM][PF₆]) is reported. The reaction time, yields and IL recyclation are also investigated and this method showed advantages over the methods described in the literature.     

Poly(arylene ether sulfone) multi-block copolymers bearing perfluoroalkylsulfonic acid groups

Poly(arylene ether sulfone) (PAES) multi-block copolymers bearing perfluoroalkylsulfonic acid moieties were prepared from hydrophilic and hydrophobic prepolymers. The latter were synthesized by reaction of N,N-diisopropylethylammonium 2,2-bis(p-hydroxyphenyl)pentafluoropropanesulfonate (HPPS) with bis-(4-fluorophenyl) sulfone (FPS), and biphenol (BP) with FPS, respectively. Prepolymers and multi-block copolymers were prepared at 180 °C in N,N-dimethylacetamide in the presence of K₂CO₃. The prepolymers were reacted overnight; the multi-block copolymers were reacted only 80 min to minimize transetherification. Prepolymers and multi-block copolymers were characterized using ¹H and ¹³C NMR. ¹⁹F NMR provided molecular weight of hydrophilic prepolymers bearing aryl fluoride end groups. GPC was used to characterize the multi-block copolymers. Copolymer block lengths were determined by quantifying ¹³C NMR peak areas of quaternary carbon atoms adjacent to sulfur in FPS moieties. Hydrophilic and hydrophobic block lengths were in the range 9.4-23.4 and 4.4-11.8 repeating units, respectively. AFM showed phase separation for all block lengths. Conductivity at 80 °C and 100% relative humidity ranged from 6.2 to 34.3 mS/cm, with the best value obtained for hydrophilic/hydrophobic block lengths of 13.3/6.0.     

Synthesis of Poly(maleic anhydride-co-taurine) as a Biodegradable Detergent Builder

Biodegradable poly(maleic anhydride-co-taurine) was synthesized by anionic ring-opening copolymerization of maleic anhydride (MA) and taurine. The structures were characterized by elemental analysis, Fourier transform infrared spectroscopy, nuclear magnetic resonance (¹H NMR) and mass spectroscopy. The weight-average molecular weight (M _w) of the copolymers was tested using multi-angle laser light scattering instrument. The biodegradability of the copolymers was judged by the shaking table test method. The possibility of the copolymers to be a detergent builder was assessed in terms of the calcium sequestration capacity which was evaluated in accordance with the China National Standard method (GB/T 21884-2008) and dispersive power test. The results showed that the copolymers were biodegradable, and possessed a high calcium sequestration capacity and a good dispersancy, which were environment-friendly detergent builders.     

Synthesis and solubility of polylactide-co-poly(amino acid) random copolymer

Random copolymers of polylactide-co-poly(amino acids) with a molecule weight range of 5,000–20,000 g/mol were obtained by ring-opening polymerization of l-lactic acid O-carboxyanhydride with amino acid-N-carboxyl anhydride in the presence of DMAP as an initiator. The structures of the copolymers were characterized with IR, ¹H-NMR, ¹³C-NMR, and GPC. The results show that the polymerization activity of amino acid-N-carboxyl anhydride is higher than that of l-lactic acid O-carboxyanhydride. Copolymers of polylactide-co-poly(amino acid) can improve the solubility of poly(amino acid) in organic solvents.     

Polyester polyol synthesis by alternating copolymerization of propylene oxide with cyclic acid anhydrides by using double metal cyanide catalyst

Ring-opening copolymerizations of propylene oxide (PO) with cyclic acid anhydrides, succinic anhydride (SA), maleic anhydride (MA) and phthalic anhydride (PA) were carried out in the presence of a double metal cyanide (DMC) catalyst of molecular formula Zn_2.3Cl_1.0[Co(CN)₆]_1.0?2.0^tBuOH?1.0H₂O as a means of developing functional polyols bearing ester backbones. Uniform alternating copolymers are produced when [PO]/[anhydride] in the copolymer approaches unity. All resulting copolymers have moderate molecular weights (M_n = 2300–10,600) and a narrow polydispersity index (1.02–1.49). The apparent reactivity ratio of PO is 0.34, 0.28, and 0.26 for PO/SA, PO/MA, and PO/PA copolymerizations, respectively, assuming that the reactivity ratio of the anhydrides is zero. The DMC-catalyzed PO copolymerizations with anhydrides are an efficient way to produce polyester polyols, expanding the versatility of conventional polyols.     

Block, blocky gradient and random copolymers of 2-ethylhexyl acrylate and acrylic acid by atom transfer radical polymerization

The controlled synthesis of low-T_g poly(2-ethylhexyl acrylate) (P2EHA) and derived random, block and blocky gradient copolymers via atom transfer radical polymerization (ATRP) is described. After optimizing the reaction conditions for the homopolymerization of 2EHA via ATRP, the synthesis of a variety of copolymers with poly(t-butyl acrylate) (PtBuA) was investigated. First, AB-block copolymers were targeted, starting from P2EHA and PtBuA as macroinitiators. Second, random copolymers of tBuA and 2EHA with different monomer ratios were synthesized. Finally, the synthesis of “blocky” gradient copolymers via a one-pot procedure was investigated, starting with the homopolymerization of tBuA, followed by the addition of 2EHA. The hydrolysis of the PtBuA-segments to poly(acrylic acid) (PAA), which was carried out with methanesulfonic acid, resulted in block, blocky gradient and random copolymers consisting of PAA and P2EHA. Solubility testing of the copolymers in slightly basic water (pH ∼ 9) demonstrated that the gradient structure significantly enhances solubility compared to the block copolymer structures with equal composition. The polymers have been characterized by MALDI-TOF MS, GPC and ¹H NMR.     

Synthesis,crystallinity and degradation properties of biodegradable poly[(sebacic anhydride)‐co‐caprolactone] triblock copolymers

BACKGROUND: A series of novel biodegradable poly[(sebacic anhydride)‐co‐caprolactone] (PSA‐co‐PCL) triblock copolymers were prepared by melt condensation of acylated PSA and monofunctional hydroxyl‐terminated PCL prepolymers. These copolymers could be used as novel drug delivery carriers with expected good drug permeability due to the PCL component. The degradation rate and mode can be modulated by varying the ratio of monomers in the copolymer. RESULTS: The homopolymers and copolymers were characterized using ¹H NMR, gel permeation chromatography and differential scanning calorimetry (DSC). ¹H NMR confirmed the formation of triblock copolymers that comprise a middle PSA block and two side PCL blocks. DSC revealed that the melting temperature and degree of crystallinity for both sebacic anhydride (SA) and caprolactone (CL) components are strongly composition dependent, implying the hindrance effect of the two components on the crystallinity. In vitro degradation experiments showed that the mass loss is significantly accelerated for samples in base buffer solution and more rapid for the copolymers with a higher SA content. Scanning electron microscopy revealed that for SA‐rich copolymer, PSA(80 wt%)‐co‐PCL, surface erosion dominated the degradation mode of the sample. In contrast, for CL‐rich copolymer, PSA(20 wt%)‐co‐PCL, a micropore structure developed at a degradation time of 155 h along the edges of the sample, owing to the hydrolysis of SA. CONCLUSION: It is concluded that the rate and mode of degradation of these copolymers can be tuned by varying the composition of the copolymers. Copyright © 2007 Society of Chemical Industry     

Polydispersity control in ring opening metathesis polymerization of amphiphilic norbornene diblock copolymers

Ring opening metathesis polymerization (ROMP) with Grubbs's catalyst was used to synthesize narrow polydispersity (PDI)diblock copolymers of norbornene (NOR) and norbornenedicarboxylic acid (NORCOOH). Norbornene (NOR) and 5-norbornene-2,3,-dicarboxylic acid bis trimethylsilyl ester (NORCOOTMS) were used as precursor monomers for thepolymerization. [NORCOOTMS]_m/[NOR]_n was converted to [NORCOOH]_m/[NOR]_n by precipitating the polymer solution in a mixture of methanol, acetic acid, and water. The conversion to 5-norbornene-2,3-dicarboxylic acid was evidenced by ¹H NMR. By polymerizing the bulkier NORCOOTMS precursor monomer first, lower PDIs were observed for the completed [NORCOOH]_m/[NOR]_n block copolymers in comparison to copolymers where the NOR block was polymerized first. The PDI of the diblock copolymers of [NORCOOH]_m/[NOR]_n decreased with increase in block length ofthe precursor NORCOOTMS monomer. This study shows that the PDI can be controlled by selecting a monomer with appropriate functionality as the starting block of the block copolymer to control the rate of propagation, R_p, as an alternative of using additives to change the reactivity of the catalyst.     

Complex-radical copolymerization of <Emphasis Type="Italic">N-</Emphasis>vinyl pyrrolidone with isostructural analogs of maleic anhydride

Radical copolymerizations of N-vinyl-2-pyrrolidone (VP) with isostructural analogs of maleic anhydride (MA), such as citraconic anhydride (CA) and N-substituted maleimides [maleimide (MI), N-ethylmaleimide (EMI) and N-phenylmaleimide (PhMI)] were studied. Compositions of copolymers synthesized in a wide range of monomer feed ratios were determined by alkali titration (for anhydride copolymers), FTIR and ¹H NMR spectroscopy using 1495 and 630 cm^-1 (for VP-MI), 1289 and 1225 cm^-1 (for VP-EMI) and 1050 and 3067 cm^-1 (for VP-PhMI) analytical bands and integral areas of CH₂ (pyrrolidone ring) and CH (MI), CH₃ (EMI) and CH= (benzene ring in PhMI) groups, respectively. Electron-donor VP monomer was found to have substantially different reactivities in the radical copolymerization with MA, CA and N-substituted (H, C₂H₅ and phenyl) malemides as electron-acceptor comonomers. Effects of H-bonding and N→O=C coordination on the monomer reactivity ratios were evaluated. Tendency to alternation of the monomer pairs increases in the order of VP–MA > VP–CA > VP-MI > VP-PhMI > VP-EMI. Structure-thermal property-relationship for the synthesized copolymers was also studied.