Optimization of biodiesel production from trap grease via acid catalysis

As a kind of waste collected from restaurants, trap grease is a chemically challenging feedstock for biodiesel production for its high free fatty acid (FFA) content. A central composite design was used to evaluate the effect of methanol quantity, acid concentration and reaction time on the synthesis of biodiesel from the trap grease with 50% free fatty acid, while the reaction temperature was selected at 95 degrees C. Using response surface methodology, a quadratic polynomial equation was obtained for ester content by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. To achieve the highest ester content of crude biodiesel (89.67%), the critical values of the three variables were 35.00 (methanol-to-oil molar ratio), 11.27 wt% (catalyst concentration based on trap grease) and 4.59 h (reaction time). The crude biodiesel could be purified by a second distillation to meet the requirement of biodiesel specification of Korea.

四川蜡瓣花、密花樫木、四川溲疏及云南豆腐柴的化学成分研究

本论文对四川蜡瓣花 (Corylopsis willmottiae Rehd. et Wils.)、密花樫木[Dysoxylum densiflorum (Blume) Miq.]、四川溲疏 (Deutzia setchuenensis Franch)及云南豆腐柴 (Premna yunnanensis W. W. Smith)的化学成分进行了研究。通过色谱分离得到44个化合物。主要基于波谱数据鉴定了它们的结构，其中1个为新化合物。 1．从四川蜡瓣花全株的95%乙醇提取物中共分离鉴定了13个化合物，它们是：1-O-(3-O-甲基没食子酸)-岩白菜素(1)、11-O-没食子酰基岩白菜素(2)、 11-O-紫丁香基岩白菜素(3) 、岩白菜素(4)、4-O-没食子酰基岩白菜素(5) 、4,11-O-二没食子酰基岩白菜素 (6)[14]、β-谷甾醇 (7)、acetyl aleuritolic acid (8)、(-)-表没食子儿茶素没食子酸酯(9)、对羟基苯甲酮 (10)、 11-香豆酸酰岩白菜素 (11)[19]、丁香酸 (12)和没食子酸 (13)。其中1为新化合物。 2．从密花樫木根的95%乙醇提取物中共分离纯化了13个化合物，它们是：β-白檀酮(14)、richenone (15)、β-谷甾醇 (7)、cabraleadiol (16)、β-香树脂醇 (17)、龙脑香醇酮 (18)、cabraleadiol monoacetate (19)、cabraleone (20)、3β-hydroxy-5 -pregnen-20-one (21)、3β-hydroxy-5α-pregnan-20-one (22)、cabraleahydroxylactone (23)、川楝子甾醇B (24)、表儿茶素 (25)。 3．从四川溲疏全株95%乙醇提取物中共分离11个化合物，鉴定了其中的9个化合物。它们是：β-谷甾醇 (7)、白桦酯醇(26)、齐墩果酸(27)、hydrangetin (28)、肉桂酸 (29)，齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸苷(30)、β-胡萝卜苷 (31)、齐墩果酸-3-O-（β-D-吡喃葡萄糖醛酸-6-正丁酯）(32)、齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸-28-O-β-D-吡喃葡萄糖苷 (33)。 4．从云南豆腐柴95%乙醇提取物中分离得到12个化合物，分别为白桦脂醇 (25)、7-羟基黄烷酮 (34)、松属素 (35)、2’,4’-羟基查儿酮 (36)、高良姜素-3-甲醚 (37) 、高良姜素-3,7-二甲醚 (38)、异甘草素-4-甲醚 (39)、豆蔻明 (40)、乔松酮 (41)、异甘草素 (42)、arjunolic acid (43)、槲皮素3-O-β-D-木糖苷(44)。 5．综述了1976年以来樫木属植物化学成分和活性研究的概况。 Phytochemical investigation on Corylopsis willmottiae, Dysoxylum densiflorum, Deutzia setchuenensis, and Premna yunnanensis, led to the isolation of 44 compounds, 1 of which was new one. 1. One new compound was isolated from 95% ehanolic extrat of the whole plants of C. willmottiae, identified as 11-O-(3-O-methylgalloyl)-bergenin (1). The twelve known compounds isolated were 11-O-galloylbergenin (2), 11-O-syringylbergenin (3), bergenin (4), 4-O-galloylbergenin (5), 4,11-di-O-galloylbergenin (6), β-sitosterol (7), acetyl aleuritolic acid (8), (-)-epigallocatechin 3-O-gallate (9), 1-(4-hydroxyphenyl) ethanone (10), 11-O-coumaroylbergenin (11), syringic acid (12), gallic acid (13). 2. Thirteen compounds were isolated from 95% ethanol extract from the roots of D. densiflorum and identified as β-amyrenone (14), richenone (15), β-sitosterol (7), cabraleadiol (16), β-amyrin (17), hydroxydammarenone-Ⅱ (18), cabraleadiol monoacetate (19), cabraleone (20), 3β-hydroxy-5-pregnen-20-one (21), 3β-hydroxy-5α-pregnan-20-one (22), cabraleahydroxylactone (23), toosendansterol B (24) and (-)-epicatechin (25). 3. Eleven compounds were isolated from ethanol extract of D. Setchuenensis. Nine were identified as β-sitosterol (7), betulin (26), oleanolic acid (27), hydrangetin (28), cinnamic acid (29), oleanolic acid 3-O-β-D-glucuronopyranoside (30), β-daucosterol (31), oleanolic acid 3-O-β-D-glucuronopyranoside-6-O-butyl ester）(32), oleanolic acid 3-O-β-D-glucuronopyranosyl-28-3-O-β-D-glucopyranoside (33). 4. Twelve compounds were isolated from ethanol extract of P. yunnanensis and identified as betulin (26), 7-hydroxyflavanone (34), pinocembrin (35), 2’,4’-dihydroxychalcone (36), galangin 3-methyl ether (37), galangin 3,7-dimethyl ether (38), isoliquiritigenin 4-methyl ether (39), cardamonin (40), pinostrobin (41), isoliquiritigenin (42), arjunolic acid (43), quercetin 3-O-β-D-lyxosopyranoside (44). 5. Chemical constituents and biological activities of the genus Dysoxylum (Meliaceae) were reviewed during 1976-2009.

手性有机小分子路易斯碱催化剂的设计、合成及其在亚胺不对称还原中的应用

手性胺是合成天然产物和手性药物的重要中间体，亚胺的不对称催化还原是制备光学活性手性胺的最直接有效的方法之一。但是，由于C＝N双键的反应活性较弱以及容易发生E/Z异构等问题，亚胺的不对称催化还原具有很大的挑战性，既具有高对映选择性又具有宽广底物普适性的催化剂很少。 本文分别由手性脯氨酸、哌啶酸、哌嗪酸以及氨基醇出发，设计和合成了一系列结构新颖、合成简便、性能优良的酰胺类有机小分子路易斯碱催化剂，以廉价的三氯氢硅为氢源，用这些催化剂催化亚胺不对称还原，得到了非常优良的收率、对映选择性和前所未有的底物普适性。 文献研究认为，除N-甲酰基外，分子内含有芳香酰胺是能催化亚胺还原的有机小分子路易斯碱催化剂具有较高对映选择性的必要条件，我们研究发现N-甲酰脯氨酸非芳香酰胺类催化剂（包括结构简单的C2-对称型脯氨酰胺类催化剂），对N-芳基酮亚胺的还原可获得达86%的对映选择性，远高于同类芳香酰胺催化剂，证明N-甲酰非芳香酰胺类路易斯碱催化剂在亚胺还原中也能得到高的对映选择性。 在进一步研究中，我们以手性六元哌啶酸为模板，分别设计合成了N-甲酰哌啶酸芳香酰胺和N-甲酰哌啶酸非芳香酰胺两类催化剂，其中芳香酰胺催化剂（S）-N-（甲酰基）哌啶-2-酸-1-萘基酰胺（28）和非芳香酰胺催化剂（2S,1'S,2'S）-N-（甲酰基）-哌啶-2-酸（1',2'-二苯基-2'-乙酰氧基-乙基）酰胺（30）显示出非常优良的催化活性和对映选择性，对于N-芳基芳香酮亚胺的还原，无论是缺电子体系还是富电子体系，绝大部分都能得到很高的收率（达98%）和对映选择性（达96% ee)。特别值得一提的是30对一些脂肪族亚胺和α,β-不饱和亚胺的还原，虽然底物为E/Z混合物，也能得到很高的收率（达93%）和对映选择性（达95% ee)，这样的底物普适性在过渡金属催化体系中也是前所未有的。 现有的催化亚胺还原的高对映选择性催化体系大多仅适用于甲基酮亚胺底物，对位阻较大的非甲基酮亚胺很难获得好的结果。我们以L-哌嗪酸为模板设计和合成出的（S）-N-（甲酰基）-哌嗪-2-酸-4-对叔丁基苯磺酰基-苯基酰胺不但对N-芳基甲基酮亚胺有很好的对映选择性（达90% ee)，而且对于大位阻的N-芳基非甲基酮亚胺有更好的对映选择性（达97% ee)。该催化剂与30在底物普适性方面具有很好的互补性。 我们还设计了基于1,2-二苯基氨基醇为模板的新型N-甲酰路易斯碱有机小分子催化剂，首次发现结构简单的N-甲酰（1S,2R）二苯基氨基醇能较好的催化N-芳基酮亚胺，最高可以得到82%的对映选择性。 针对我们设计合成的结构新颖、性能优良的催化剂，我们对催化机理进行了探讨和解释，提出了几个假想的机理模型。 Catalytic enantioselective reduction of imines represents one of the most straightforward and efficient methods for the preparation of chiral amines, an important intermediate for the synthesis of natural products and chiral drugs. However, asymmetric reduction of imines remains a big challenge and highly enantioselective catalysts with a satisfactorily broad substrate scope remain elusive. Factors contributing to the difficulty of this transformation include the weak reactivity of the C=N bond and the existence of inseparable mixtures of E/Z isomers. Starting from chiral proline, pipecolinic acid, piperazine-2-carboxylic acid and 1,2-diphenyl amino alcohol, a series of structurally simple and easily prepared amides were developed as highly effective Lewis basic organocatalysts for the asymmetric reduction of imines with trichlorosilane as the reducing agent, which promoted the reduction of N-aryl imines with high yields and excellent enantioselectivities with an unprecedented substrate spectrum. In the literature, it has been believed that besides the N-formyl group, the existence of an arylamido group in the structure of Lewis basic organocatalysts is a prerequisite for obtaining high enantioselectivity in the catalytic reduction of imines. However, we found that the N-formyl-L-prolinamides bearing non-arylamido groups, including structurally simple C2-symmetric tetraamides, could also work as effective Lewis basic catalysts to promote the asymmetric reduction of ketimines with high enantioselectivities (up to 86% ee), which are even more enantioselective than the analogues with arylamido groups. In further studies, we developed novel N-formamides with arylamido groups and non-arylmido groups as Lewis basic catalysts using the commercially available L-pipecolinic acid as the template. The catalysts (S)-1-formyl-piperidine-2-carboxylic acid naphthylamide 28 and (2S,1'S,2'S)-acetic acid 2-[(1-formyl-piperidine-2-carbonyl) -amino]-1,2-diphenyl-ethyl ester 30 were found to promote the reduction of a broad range of N-aryl imines in high yields (up to 98%) and excellent ee values (up to 96%) under mild conditions. Furthermore, catalyst 30 also exhibited high enantioselectivities (up to 95% ee) for the challenging aliphatic ketimines and α,β-unsaturated imines despite that these imines exist as E/Z isomeric mixtures. The broad substrate spectrum of this catalyst is unprecedented in catalytic asymmetric imine reduction, including transition-metal-catalyzed hydrogenation processes. Many of the currently available highly enantioselective catalytic systems only tolerate methyl ketimines, which gave poor results for bulkier non-methyl ketimines. Starting from L-piperazine-2-carboxylic acid, we developed (S)-4-(4-tert- butylbenzenesulfonyl)-1-formyl-N-phenyl-piperazine-2-carboxamide as highly enantioselective Lewis basic catalysts for the hydrosilylation of both methyl ketimines and steric bulky non-methyl ketimines. Moreover, higher enantioselectivities were obtained for non-methyl ketimines than methyl ketimines under the catalysis of this catalyst. Thus, this catalyst system complements with 30 in terms of the substrate scope. We also found that easily accessible (1R,2S)-N-formyl-1,2-diphenyl- 2-aminoethanol worked as an effective Lewis basic catalyst in the enantioselective hydrosilylation of ketimines, affording high enantioselectivities (up to 82% ee) for a broad range of ketimines. To rationalize the high efficiencies of the structurally novel catalysts we developed, several catalytic models have been proposed.

Selective Extraction of Mercury(II) by 1-Naphthylthiourea-Methyl Isobutyl Ketone System

Selective extraction of Mercury(II) using 1-naphthylthiourea-methyl isobutyl ketone (ANTU-MIBK) system from hydrochloric acid solutions (0.1-10 M) has been studied. Influence of foreign ions, acid and ligand concentrations has been investigated. Addition of ANTU in MIBK enhanced, extraction capacity of MIBK to several times. Low effect of foreign ions and high separation factors for a number of metal ions determined at 0.5 M hydrochloric acid concentration evaluated the proposed method efficient and selective. The experimental data obtained from application of the method for extraction of mercury from a synthetic aqueous solution reveal that more than 99% mercury can be separated from cadmium, zinc and selenium in a single step with five minutes equilibration

A strategy for synthesis of ion-bonded amphiphilic miktoarm star copolymers via supramolecular macro-RAFT agent

Amphiphilic supramolecular miktoarm star copolymers linked by ionic bonds with controlled molecular weight and low polydispersity have been successfully synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization using an ion-bonded macromolecular RAFT agent (macro-RAFT agent). Firstly, a new tetrafunctional initiator, dimethyl 4,6-bis(bromomethyl)-isophthalate, was synthesized and used as an initiator for atom transfer radical polymerization (ATRP) of styrene to form polystyrene (PSt) containing two ester groups at the middle of polymer chain. Then, the ester groups were converted into tertiary amino groups and the ion-bonded supramolecular macro-RAFT agent was obtained through the interaction between the tertiary amino group and 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid (DMP). Finally, ion-bonded amphiphilic miktoarm star copolymer, (PSt)(2)-poly(N-isopropyl-acrylamide)(2), was prepared by RAFT polymerization of N-isopropylacrylamide (NIPAM) in the presence of the supramolecular macro-RAFT agent. The polymerization kinetics was investigated and the molecular weight and the architecture of the resulting star polymers were characterized by means of H-1-NMR, FTIR, and GPC techniques. (c) 2008 Wiley Periodicals, Inc.

A Biodegradable Diblcok Copolymer Poly(ethylene glycol)-block-poly(L-lactide-co-2-methyl-2-carboxyl-propylene carbonate): Docetaxel and RGD Conjugation

A diblcok copolymer monomethoxy poly (ethylene glycol)-block-poly(L-lactide-co-2-methyl-2-carboxyl-propylene carbonate) (MPEG-b-P(LA-co-MCC)) was obtained by copolymerization of L-lactide (LA) and 2-methyl-2-benzoxycarbonyl-propylene carbonate (MBC) and subsequent catalytic hydrogenation. The pendant carboxyl groups of the copolymer MPEG-b-P(LA-co-MCC) were conjugated with antitumor drug docetaxel and tripeptide arginine-glycine-aspartic acid (RGD), respectively.

Synthesis and characterisation of novel functional polyolefin containing sulfonic acid groups

The strong polar group, sulfonic acid, has successfully been introduced into ethylene/allylbenzene copolymers without degradation or crosslinking via chlorosulfonation reaction with chlorosulfonic acid as a chlorosulforiating agent in 1, 1,2,2-tetrachloroethane followed by hydrolysis. The degree of sulforiation (DS) can be easily controlled by changing the ratio of chlorosulfonic acid to the pendant phenyls of the copolymer. The microstructure of sulfonated copolymers were unambiguously revealed by H-1 NMR and H-1-H-1 COSY spectral analyses, which indicates that all the sulforiation reactions exclusively took place at the para-position of the aromatic rings.

Core Crosslinking of Biodegradable Block Copolymer Micelles Based on Poly(ester carbonate)

A biodegradable amphiphilic block copolymer, PEG-b-P(LA-co-MAC), was used to prepare spherical micelles consisting of a hydrophobic P(LA-co-MAC) core and a hydrophilic PEG shell. To improve their stability, the micelles were crosslinked by radical polymerization of the double bonds in the hydrophobic blocks. The crosslinked micelles had similar sizes and a narrow size distribution compared to their uncrosslinked precursor. The improved stability of the crosslinked micelles was confirmed by measurements of the CMC and a thermodynamic investigation. These micelles can internalize into Hela cells in vitro as demonstrated by inverted fluorescence microscopy and CLSM. These stabilized nanoscale micelles have potential use in biomedical applications such as drug delivery and disease diagnosis.

Isothermal Crystallization Behavior of Poly(L-lactic acid)/Organo-Montmorillonite Nanocomposites

The isothermal crystallization behavior of poly(L-lactic acid)/organo-montmorillonite nanocomposites (PLLA/OMMT) with different content of OMMT, using a kind of twice-functionalized organoclay (TFC), prepared by melt intercalation process has been investigated by optical depolarizer. In isothermal crystallization from melt, the induction periods (t(i)) and half times for overall PLLA crystallization (100 degrees C <= T-c <= 120 degrees C) were affected by the temperature and the content of TFC in nanocomposites. The kinetic of isothermal crystallization of PLLA/TFC nanocomposites was studied by Avrami theory. Also, polarized optical photomicrographs supplied a direct way to know the role of TFC in PLLA isothermal crystallization process. Wide angle X-ray diffraction (WAXD) patterns showed the nanostructure of PLLA/TFC material, and the PLLA crystalline integrality was changed as the presence of TFC. Adding TFC led to the decrease of equilibrium melting point of nanocomposites, indicating that the layered structure of clay restricted the full formation of crystalline structure of polymer.

Hydrogen Bonding and Crystallization in Biodegradable Multiblock Poly(ester urethane) Copolymer

The hydrogen bonding and crystallization of a biodegradable poly(ester urethane) copolymer based on poly(L-lactide) (PLLA) as the soft segment were investigated by FTIR. On slow cooling from melt, the onset and the progress of the crystallization of the urethane hard segments were correlated to the position, width, and relative intensity of the hydrogen-bonded N-H stretching band. The interconversion between the "free" and hydrogen-bonded N-H and C=O groups in the urethane units in the process was also revealed by 2D correlation analysis of the FTIR data. The crystallization of the PLLA soft segments was monitored by the ester C=O stretching and the skeletal vibrations. It was revealed that the PLLA crystallization was restricted by the phase separation and the urethane crystallization, and at cooling rates of 10 degrees C/min or higher, the crystallization of the PLLA soft segments was prohibited.

SYNTHESIS AND CHARACTERIZATION OF HYPERBRANCHED VINYL POLYMERS FROM RAFT POLYMERIZATION OF AN ASYMMETRIC DIVINYL MONOMER

Hyperbranched vinyl polymers were prepared by reversible addition-fragmentation chain transfer ( RAFT) polymerization of a styrenic asymmetric divinyl monomer. This was achieved by using cumyl dithiobenzoate or S-dodecyl-S'-(alpha,alpha'-dimethyl-alpha ''-acetic acid) trithiocarbonate as the chain transfer agent, 1,1'-azobis(cyclohexanecarbonitrile) or thermal initiation as a source of radicals. Cross-linking was inhibited by a rapid RAFT-based equilibrium between active propagation chains and dormant species, and thus a hyperbranched polymer with a monomer conversion as high as 80% was obtained. The hyperbranched structure and properties of the resultant polymers were characterized by a combination of H-1-NMR spectroscopy and a triple detection size exclusion chromatography (TRI-SEC). The hyperbranched vinyl polymer has a broad molecular weight distributions and a low Mark-Houwink exponent alpha value compared with the linear counterpart.

Investigation of heptakis(2,6-di-O-methyl)-beta-cyclodextrin inclusion complexes with flavonoid glycosides by electrospray ionization mass spectrometry

The non-covalent complexes between three flavonoid glycosides (quercitrin, hyperoside and rutin) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CD) were investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). The 1:1 complexation of each flavonoid glycoside (guest) to the DM-beta-CD (host) was monitored in the negative ion mode by mixing each guest with an up to 30-fold molar excess of the host. The binding constants for all complexes were calculated by a linear equation in the order: DM-beta-CD:quercitrin > DM-beta-CD:rutin > DM-beta-CD:hyperoside. A binding model for the complexes has also been proposed based on the binding constants and tandem mass spectrometric data of these complexes.

Preparation of poly(acrylamide-co-acrylic acid) aqueous latex dispersions using anionic polyelectrolyte as stabilizer

High-solids, low-viscosity, stable poly(acrylamide-co-acrylic acid) aqueous latex dispersions were prepared by the dispersion polymerization of acrylamide (AM) and acrylic acid (AA) in an aqueous solution of ammonium sulfate (AS) medium using anionic polyelectrolytes as stabilizers. The anionic polyelectrolytes employed include poly(2-acrylamido-2-methylpropanesulfonic acid sodium) (PAMPSNa) homopolymer and random copolymers of 2-acrylamido-2-methylpropanesulfonic acid sodium (AMPSNa) with methacrylic acid sodium (MAANa), acrylic acid sodium (AANa) or acrylamide (AM). The influences of stabilizer's structure, composition, molecular weight and concentration, AA/AM molar feed ratio, total monomer, initiator and aqueous solution of AS concentration, and stirring speed on the monomer conversion, the particle size and distribution, the bulk viscosity and stability of the dispersions, and the intrinsic viscosity of the resulting copolymer were systematically investigated. Polydisperse spherical as well as ellipsoidal particles were formed in the system. The broad particle size distributions indicated that coalescence of the particles takes place to a greater extent.

Study of hydrogen-bonded blend of polylactide with biodegradable hyperbranched poly(ester amide)

Polylactide (PLA) was melt blended with a biodegradable hyperbranched poly(ester amide) (HBP) to enhance its flexibility and toughness without sacrificing comprehensive performance. The advantage of using HBP was due to its unique spherical shape, low melt viscosity, and abundant functional end groups together with its easy access. Rheological measurement showed that blending PLA with as little as 2.5% HBP resulted in a 40% reduction of melt viscosity. The glass transition temperature (T-g) of PLA in the blends decreased slightly with the increase of HBP content, indicating partial miscibility which resulted from intermolecular interactions via H-bonding. The H-bonding involving CO of PLA with OH and NH of HBP was evidenced by FTIR analysis for the first time. The HBP component, as a heterogeneous nucleating agent, accelerated the crystallization rate of PLA. Remarkably, with the increase of HBP content, the elongation at break of PLA blends dramatically increased without severe loss in tensile strength, even the tensile strength increased within 10% content of HBP. The stress-strain curves and the SEM photos of impact-fractured surface showed the material changed from brittle to ductile failure with the addition of HBP. Reasonable interfacial adhesion via H-bonding and finely dispersed particulate structure of HBP in PLA were proposed to be responsible for the improved mechanical properties.

Synthesis of novel functional polyolefin containing carboxylic acid via Friedel-Crafts acylation reaction

The strong polar group, carboxylic acid, has triumphantly been introduced into ethylene and allylbenzene copolymers without obvious degradation or crosslinking via Friedel-Crafts (F-C) acylation reaction with glutaric anhydride (GA), succinic anhydride (SA) and phthalic anhydride (PA) in the presence of anhydrous aluminum chloride in carbon disulfide. Some important reaction parameters were examined in order to optimize the acylation process. In the optimum reaction conditions, almost all of the phenyls can be acylated with any anhydride. The microstructure of acylated copolymer was characterized by Fr-IR, H-1 NMR and H-1-H-1 COSY. All the peaks of acylated copolymers can be accurately attributed, which indicates that all the acylation reactions occur only at the para-positions of the substituent of the aromatic rings. The thermal behavior was studied by differential scanning calorimetry (DSC), showing that the melting temperatures (T(m)s) of acylated copolymers with GA firstly decrease slowly and then increase significantly with the increase of the amount of carboxyl acid groups.