Production of biodiesel from palm fatty acid distillate using sulfonated-glucose solid acid catalyst:Characterization and optimization

A palm fatty acid distillate (PFAD) has been used for biodiesel production. An efficient sulfonated-glucose acid catalyst (SGAC) was prepared by sulfonation to catalyze the esterification reaction. The effect of three variables i.e. methanol-to-PFAD molar ratio, catalyst amount and reaction time, on the yield of PFAD esters was studied by the response surface methodology (RSM). The optimum reaction conditions were:12.2:1 methanol-to-PFAD molar ratio, 2.9%catalyst concentration and 134 min of time as predicted by the RSM. The reaction under the optimum conditions resulted in 94.5%of the free fatty acid (FFA) conversion with 92.4%of the FAME yield. The properties of the PFAD esters were determined according to biodiesel standards.     

非均相羰基氧化一步合成碳酸二苯酯的研究(Ⅴ)筛选催化剂及优化合成条件

Pd/LaxPbyMnOz, Pd/C, Pd/molecular sieve and Pd-heteropoly acid catalysts for direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction were compared and the results of DPC synthesis indicated that the catalyst Pd/LaxPbyMnOz had higher activity. The Pd/LaxPbyMnOz catalyst and the support was characterized by XRD, SEM and TEM, the main phase was Lao.szPbo.asMnOa and the average diameter could be about 25.4nm. The optimuna conditions for synthesis of DPC with Pd/LasPbyMnOz were determined by orthogonal experiments and the experimental results showed that reaction temperature was the first factor of effect on the selectivity and yield of DPC, and the concentration of O2 in gas phase also had significant effect on selectivity of DPC. The optimum reaction conditions were catalyst/phenol mass ratio l to 50, pressure 4.5MPa, volume concentration of O2 25%, reaction temperature 60℃ and reaction time 4 h. The maximum yield and average selectivity could reach 13% and 97% respectively in the     

Synthesis and characterization of poppy seed oil methyl esters

Response surface methodology(RSM) was used to determine the optimum conditions of the methanolysis of crude poppy seed oil using Na OCH3 as catalyst. The experiments were run according to five levels, four variable central composite rotatable design(CCRD) using RSM. The reaction variables, i.e., molar ratio of methanol/oil(3:1–9:1), catalyst concentration(0.5 wt%–1.25 wt% Na OCH3), reaction temperature(25–65 °C), and reaction time(20–90 min) were studied. We demonstrated that the molar ratio of methanol/oil, catalyst concentration,and reaction temperature were the significant parameters affecting the yield of poppy seed oil methyl esters(PSOMEs). The optimum transesterification reaction conditions, established using the RSM, which offered a89.35% PSOME yield, were found to be 7.5:1 molar ratio of methanol/oil, 0.75% catalyst concentration, 45 °C reaction temperature, and 90 min reaction time. The proposed process provided an average biodiesel yield of more than 85%. A linear correlation was constructed between the observed and predicted values of the yield.The gas chromatography(GC) analyses have shown that PSOMEs contain linoleic-, oleic-, palmitic-, and stearic-acids as main fatty acids. The FTIR spectrum of the PSOMEs was also analyzed to confirm the completion of the transesterification reaction. The fuel properties of the PSOMEs were discussed in light of biodiesel standards(ASTM D 6751 and EN 14214).     

磁性聚合物微球在Cr(VI)吸附分离中的应用(英文)

The magnetic poly-(methacrylate-divinyl benzene) microspheres with micron size were synthesized by modified suspension polymerization method.Adsorption of Cr(VI) from aqueous solution by magnetic poly-(MA-DVB) microspheres with surface amination was investigated.The adsorption processes were carried out under diversified conditions of pH value,adsorption time and temperature to evaluate the performance of the mag-netic microspheres.The optimum pH value for Cr(VI) adsorption was found as 3.The adsorption capacity increased with adsorption time and attained an optimum at 60 min.The adsorption processes for magnetic microspheres was endothermic reaction,and the adsorption capacity increased with increasing temperature.     

Preparation of an amphoteric flocculant having both high polymer content and low viscosity and its polymerization kinetics

It is not easy for liquid cationic flocculant diallyldimethyl-ammonium chloride(DM) homopolymer to simultaneously exhibit both low viscosity and high polymer content, which limited its application in offshore oilfield.In this paper, sodium allylsulfonate(XS) and sodium formate were used in the aqueous solution polymerization of DM.An amphoteric flocculant(PDMXS) with the properties of high polymer content(about 55 wt%) and low viscosity(efflux time measured by an Apply 4 viscometer was less than 100 s) was prepared.The optimum reaction conditions were identified as follows: the mass ratio of XS/DM was 10 wt%, the concentration of sodium formate was 2000 mg·L~(-1), reaction temperature was 55 ℃, the concentration of KPS was 0.5 wt% and the reaction time was 4 h.The polymerization kinetics was discussed.The results showed that R_p∝ [M]~(1.97)[I]~(0.68)[CTA]~(0.71) and the apparent activation energy was 72.55 kJ·mol~(-1).     

Oxidation of benzyl alcohols to ketones and aldehydes by O3 process enhanced using high-gravity technology

In this study, a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O_3) reactor has been developed. Using 1-phenylethanol as a model reactant, the performance of RPB-O_3 process in different solvents has been compared with the commonly used stirred tank reactor(STR-O_3). Ethyl acetate was the optimum solvent for the conversion of 1-phenylenthanol to acetophenone in RPB-O_3 process, with 78% yield after 30 min. In a parallel STR-O_3 experiment, the yield of acetophenone was50%. Other experimental variables, i.e. O_3 concentration, reaction time, high-gravity factor and liquid flow rate were also optimized. The highest yield of acetophenone was obtained using O_3 concentration of 80 mg·L~(-1),reaction time of 30 min, high gravity factor of 40 and liquid flow rate of 120 L·h~(-1). Under the optimized reaction conditions, a series of structurally diverse primary and secondary alcohols was oxidized with(19%–92%) yield.The ozonization mechanism was studied by Electron Paramagnetic Resonance(EPR) spectroscopy, monitoring the radical species formed upon self-decomposition of O_3. The characteristic quadruple peak with the 1:2:2:1 intensity ratio that corresponds to hydroxyl radicals(·OH) was observed in the electron paramagnetic resonance(EPR) spectrum, indicating an indirect oxidation mechanism of alcohols via ·OH radical.     

神经二肽N-乙酰天门冬氨酰谷氨酸的合成

The synthesis process of N-acetyl-aspartyl-glutamate (NAAG) was studied, in which L-aspartic acid was used as the raw material, and the dipeptide was first prepared by esterification,acylation and the reaction with L-glutamic acid, and then the product NAAG was finally obtained by hydrolyzation and purification.The product and the intermediate were analyzed and identified by melting point measuring, elemental analysis, polarimeter and IR analysis.The effects of mixture ratio of raw materials, reaction temperature and reaction time were investigated.The results showed that the total yield was 50.02% when the esterification temperature was controlled at 20℃, esterification time 10 h, acylation temperature 70℃, acylation time 2 h, and DCC was used as the addition reagent to synthesize dipeptide.The hydrolization temperature was 60℃, the hydrolization time was 4 h.The product was purified by ion-exchange resin.The purity detected by HPLC was 97.5%.     

超重力场中重氮盐水解制备对羟基苯甲醛

A new type of reactor,featured with impinging stream-rotating packed bed(IS-RPB)and coil pipes,was designed and used to prepare p-hydroxybenzaldehyde(PHB)by hydrolysis from diazonium salts.The influence of operating parameters,such as reaction temperature,reaction time and high gravity factor,on the yield of PHB was investigated.Compared with the traditional kettle-type reactor,the yield of PHB with the new reactor is increased significantly and the reaction time is much shorter.Under the optimum conditions,the yield of PHB is increased from 51%to 84.1%.The reactor offers an opportunity for replacing the traditional batch mode operation with a continuous process.     

硅烷处理N2O氧化苯生产苯酚催化剂抑制结碳失活研究

The main cause to the deactivation of ZSM-5 catalyst, used for oxidation of benzene to phenol (BTOP) by nitrous oxide, is that the carbon deposition on the catalyst surface blocks the mouth of pores of the catalyst.In the experiments, ZSM-5 catalyst was modified by chemical surface deposition of silicon, and then the effect of modification condition on the catalyst activation was studied. The catalyst samples were characterized by XRF,EPS, XRD, TEM, N2 adsorption at low temperature, pyridine adsorption-infrared technique and etc. All the above results show that the uniform SiO2 membrane can be formed on ZSM-5 crystal surface. The SiO2 membrane covers the acid centers on ZSM-5 surface to inhibit surface coking, to avoid or decrease the possibility of ZSM-5 pore blockage so that the catalyst activity and stability can be improved efficiently. The optimum siliconiting conditions determined by the experiments are as follows: 4% load of silanizing agent, volume (ml)/mass (g) ratio of hexane/ZSM-5=15/1, and 16 h of modification time. Compared with the samples without siliconiting treatment,the samples treated under the above optimum condition can increase the productivity of phenol by 14% for 3 h reaction time and by 41% for 6 h reaction time respectively.     

A safe and efficient process for the preparation of difluoromethane in continuous flow

Difluoromethane is typically produced vialiquid-phase fluorination as performed in a batch reactor. However,this process suffers from some problems, e.g., severe corrosion of the reactor, high safety risk, and the regeneration of the catalyst. In this paper, a flow process as performed in the tubular reactor was designed. The optimum conditions for continuous synthesis of difluoromethane were obtained as follows: the reaction temperature was 100℃, the molar ratio of dichloromethane to hydrogen fluoride was 1.6:1 and the reaction time was 300 s. The operation of the cyclic process was stable for 24 h with the conversion per pass of hydrogen fluoride up to 16.2%.The unreacted raw materials were easily reused. The deactivation of the common catalyst, antimony pentachloride, was investigated by catalyst concentration curve and XPS analysis. The approach proposed in this work is proven to be safe, efficient and low amount of catalyst.     

A pH‐sensitive porous chitosan membrane prepared via surface grafting copolymerization in supercritical carbon dioxide

We report the successful grafting copolymerization of acrylic acid (AA) on a crosslinked porous chitosan membrane in supercritical carbon dioxide at pressures ranging from 13 to 25 MPa with the use of benzyl peroxide (BPO) as the reduction–oxidation free radical initiator. The effects of reaction pressure, initiator concentration, monomer concentration, reaction temperature and reaction time on grafting yield (GY) were investigated. GY initially increases and then decreases with increasing polymerization temperature and AA and BPO concentrations. The optimum grafting conditions to obtain maximum GY are as follows: 8 h reaction time, 80 °C reaction temperature, 3.05 × 10^?2 g mL^?1 AA concentration, 3 × 10^?3 g mL^?1 BPO concentration and 16 MPa reaction pressure. The water flux of the grafted chitosan membranes decreases with pH from 2 to 7, even at considerably low GY (0.95 wt%). A novel and green modification method has been developed for the preparation of biopolymer‐based membranes. © 2014 Society of Chemical Industry     

PE塑料胶黏剂的研制

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,通过自由基聚合,采用丙烯酸(AA)接枝改性氯化聚丙烯(CPP),得到一种PE胶黏剂。研究了反应温度、反应时间、AA和BPO的质量对CPP胶黏剂改性的黏附性能的影响;得出较佳的工艺条件为:反应温度T=90℃,反应时间t=3h,反应物料的质量比m(CPP):m(AA):m(BPO)=100:3.0:0.5时,改性的CPP胶黏剂有较高的黏接强度。     

丙烯酸与异形聚酯共混纤维接枝共聚研究

以过氧化苯甲酰为引发剂,丙烯酸为单体与碱处理后的异形聚酯共混纤维接枝共聚,井对接枝后的异形聚酯共混纤维进行了结构和性能研究。结果表明:BPO浓度在0．01 moL／L,丙烯酸浓度1．50 mol/L,聚合温度85℃,时间90 min,所获得的接枝率为12％。随着接枝率的上升,热稳定性下降,回潮率增加,抗静电性能增加。     

Modification of polypropylene fiber by radiation-induced graft copolymerization of acrylonitrile monomer

Modification of polypropylene fiber was carried out by graft copolymerization of acrylonitrile monomer using the preirradiation method. The influence of synthesis conditions (preirradiation dose, monomer concentration, temperature, draw ratio, and storage) on the degree of grafting was investigated. For all preirradiation doses, the degree of grafting was found to increase with the reaction time. The higher the preirradiation dose, the higher the degree of grafting was. The dilution of monomer with DMF showed peak maxima for the degree of grafting at 80% monomer concentration. Both the initial rate of grafting and the final degree of grafting were found to increase with an increase in the reaction temperature. An activation energy of 31.2 kJ/mol was found for the grafting reaction. The degree of grafting in the drawn fiber showed different behavior as compared to the undrawn fiber. The storage of the irradiated fiber at −4°C prior to the grafting showed a decrease in the degree of grafting initially for a period of 8 days, beyond which the degree of grafting remained constant. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1343–1348, 1998     

Optimized conditions for the grafting reaction of poly(methyl acrylate) onto rubberwood fiber

Graft copolymerization of poly(methyl acrylate) (PMA) onto rubberwood fiber (RWF) was carried out by free radical initiation. Hydrogen peroxide and ferrous ions were used as an initiator system. Effects of various parameters (reaction temperature and reaction time, as well as hydrogen peroxide, ferrous ammonium sulfate and monomer concentrations) on the grafting percentage were investigated. A high percentage of grafting was achieved when optimum reaction conditions were used. The optimum temperature of the reaction was determined to be about 55 °C and the reaction time was 120 min. The optimum concentration of H₂O₂ was 0.03 M and the amounts of Fe²⁺ and MA were 0.4 mmol and 0.05 mol, respectively. The PMA homopolymer was removed from the graft copolymer by Soxhlet extraction using acetone. The presence of PMA on the fiber was confirmed by FT-IR spectroscopy and gravimetry. The surface morphology of the poly(methyl acrylate)-graft-(rubberwood fiber) was studied by means of scanning electron microscopy. Copyright © 2004 Society of Chemical Industry     

马来酸酐固相接枝聚丙烯纤维

了提高非极性聚丙烯纤维(PP)的相容性,采用固相法以马来酸酐(MAH)对聚丙烯纤维进行接枝改性,研究了反应条件对接枝率的影响。结果表明,马来酸酐成功接枝到聚丙烯上,当反应温度为80℃,PP用量为0.5 g,MAH用量为0.2 g,BPO用量为0.05 g,回流时间为2.5 h时,最大接枝率可达到7.51%;BPO的用量、MAH单体的用量以及反应温度对PP纤维的接枝率影响较大。而测定PP纤维接枝率时回流时间对其接枝率的影响不大;接枝聚丙烯纤维的分解温度明显高于纯聚丙烯纤维。     

粘胶纤维接枝共聚研究

用高锰酸钾为引发剂 ,将粘胶纤维与丙烯酸接枝共聚 ,研究了接枝共聚反应工艺条件对接枝率的影响。结果表明 :高锰酸钾浓度 ,预处理温度、时间 ,硫酸浓度 ,丙烯酸浓度 ,反应温度、时间均与接枝率有关 ,反应中选择高锰酸钾浓度 0 .0 7mol/ L ,预处理温度 5 0℃、时间 2 0 min,硫酸浓度 0 .0 8mol/ L ,丙烯酸浓度 1.2 m ol/ L ,反应温度 90℃ ,粘胶纤维接枝率可高达 72 %。     

高锰酸钾引发聚酯纤维接枝共聚改性研究

研究了用KMnO_4/H_2SO_4作为引发剂,聚酯(PET)纤维与丙烯酸接枝共聚的改性方法,探讨了间甲酚浸泡时间和温度、KMnO_4浓度、H_2SO_4浓度、丙烯酸(AA)浓度等对接枝率的影响。结果表明:间甲酚浸泡时间2h、浸泡温度60℃、KMnO_4浓度3.0×10~(-3)mol/L、H_2SO_4浓度0.02mol/L、AA浓度2.66mol/L、反应时间2h时,PET纤维的接枝率较高;同时,用红外光谱证明了聚丙烯酸接枝支链的存在。     

聚丙烯纤维接枝苯乙烯的研究

采用化学接枝法以苯乙烯(St)为接枝单体、过氧化苯甲酰(BPO)为引发剂,1,2-二乙烯苯(DVB)为交联剂、甲醇和正辛醇为溶剂,对聚丙烯(PP)纤维进行接枝改性。研究了原料配比和反应条件对其接枝的影响。结果表明,PP纤维上接枝St,适宜的原料配比和操作条件为:St质量与PP体积比(St/PP)为4,BPO质量与St体积比(BPO/St)为0.025,DVB与St体积比(DVB/St)为0.025,溶剂与St体积比为5,浸渍24～30h,在85℃恒温水浴中反应6～8h。在较佳条件下可得到导入率为110%-160%的接枝纤维。     

聚酯纤维光化学接枝共聚改性的研究

研究了聚酯纤维与丙烯酸光化学引发接枝共聚的改性方法,探讨了溶胀时间与温度、二苯甲酮(BP)浸泡时间与浓度、辐照时间、单体浓度等因素对接枝率的影响。实验结果表明:当间甲酚的溶胀时间为2h、溶胀温度为60℃、BP的丙酮浓度为0.2 mol/L、BP的丙酮浸泡时间为1h、光照时间为2h、丙烯酸浓度为0.9mol/L时,聚酯纤维的接枝率较高;同时,用红外光谱证明了聚丙烯酸接枝链的存在。