共查询到20条相似文献,搜索用时 93 毫秒
1.
The hydrolysis technology and reaction kinetics for amino acids production from fish proteins in subcritical water reactor without catalysts were investigated in a reactor with volume of 400 ml under the conditions of reaction temperature from 180-320℃, pressure from 5-26 MPa, and time from 5-60 rain. The quality and quantity of amino acids in hydrolysate were determined by bioLiquid chromatography, and 17 kinds of amino acids were obtained. For the important 8 amino acids, the experiments were conducted to examine the effects of reaction temperature, pressure and time on amino acids yield. The optimum conditions for high yield are obtained from the experimental results. It is found that the nitrogen and carbon dioxide atmosphere should be used for leucine, isoleucine and histidine production while the air atmosphere might be used for other amino acids. The reaction time of 30 rain and the experimental temperature of 220℃, 240℃ and 260℃ were adopted for reaction kinetic research. The total yield of amino acids versus reaction time have been examined experimentally. According to these experimental data and under the condition of water excess, the macroscopic reaction kinetic equation of fish proteins hydrolysis was obtained with the hydrolysis reaction order of 1.615 and the rate constants being 0.0017, 0.0045 and 0.0097 at 220℃, 240℃ and 260℃ respectively. The activation energy is 145.1 kJ·mol^- 1. 相似文献
2.
有机硅改性水性环氧固化剂的合成及表征 总被引:6,自引:0,他引:6
A novel waterborne epoxy curing agent was prepared using 3-glycidoxypropyl trimethoxysilane (GPTMS) as a termination agent of adduct, which was synthesized by triethylene tetramine (TETA) and liquid epoxy resin (E-51). The effects of the reaction temperature and time on the synthesis process were investigated experimentally. The particle size and the distribution of water dispersion of the curing agent were measured by dynamic light scattering(DLS). The structure of the products was characterized by Fourier transform infrared spec-trometer (FTIR) and ^1H-nuclear magnetic resonance (^1H NMR). The properties of the synthesized curing agent and the epoxy resin film cured by it were also measured. The results showed that the appropriate temperature for the synthesis of adduct was at 65-75℃ and the reaction time was 4-5h, and that the suitable reaction temperature of curing agent synthesis was 75-85℃ and the reaction time was 3-4h. When the mass ratios of GPTMS and acetic acid were 3%-5% and 5%-10% respectively, the hardness, water resistance and adhesion of the cured film were improved significantly. 相似文献
3.
The catalytic effects of single and mixed catalysts, i.e. single 3%Ca and 5%Na-BL(black liquor) catalysts and mixed 3%Ca+5%Na-BL catalyst, on carbon conversion, gasification reaction rate constant and activation energy, relative amount of harmful pollutant like sulphur containing gases have been investigated by thermogravimetry in steam gasification under temperature 750℃ to 950℃ at ambient pressure for three high-metarnorphous anthracites (Longyan, Fenghai and Youxia coals in Fujian Province). The mixed catalyst of 3%Ca+5%Na-BL increases greatly the carbon conversion and gasification rate constant by accelerating the gasification reaction C+H2O→CO+H2 due to presence of alkali surfacecompounds [COM], [CO2M] and exchanged calcium phenolate and calcium carboxylate (-COO)2. By adding CaCO3 into BL catalyst in gasification, in addition to improving the catalyst function and enhancing the carbon conversion, the effective desulphurization is also achieved, but the better operating temperature should be below 900℃. The homogenous and shrinking core models can be successfully employed to correlate the relations between the conversion and the gasification .time .and to estimate the reaction rate constant, The reaction acUvaUon energy and pre-exponential factor are estimated and the activation energy for mixed catalyst is in a range of 98.72-166.92 kJ·mol^-1, much less than 177.50-196.46 kJ·mol^-1 for non-catalytic steam gasification for three experimental coals. 相似文献
4.
聚丙烯纤维接枝丙烯酸反应条件优化 总被引:7,自引:0,他引:7
The optimum conditions of grafting copolymerization reaction of acrylic acid (AA) onto polypropylene (PP) fiber was studied by using benzoyl peroxide (BPO) as initiator. The primary and secondary sequences of the grafting copolymerization reaction conditions was analysed. The results showed that grafting copolymerization reaction was greatly influenced by the temperature, reaction time, concentration of BPO and that of AA in the primary and secondary role as the above sequence. The optimum reaction conditions of gaining higher exchange capacity for the weak acidic cation-exchange fiber are as follows: the grafting temperature 80℃, the reaction time 7h, the concentration of BPO 2% and AA 80%. 相似文献
5.
Asymmetric synthesis of (-)-1-trimethylsilyl-ethanol with immobilized Saccharomyces cerevisiae cells in water/organic solvent biphasic system was studied,The effects of shake speed,hydrophobictiy of organic solvent ,volume ratio of water phase to organic phase,pH value of aqueous phase and reaction temperature on the initial reaction rate,maximum yield and enantiomeric excess(ee) of the product were systematically explored,All the above-mentioned factors had significant infuence on the reaction.n-Hexane was found to be the best organic solvent for the reaction.The optimum shake speed,volume ratio of water phase to organic phase,pH value and reaction temperature were 150 r.min^-1,1/2,8 and 30℃ respectively,under which the maximum yield and enantiomeric excess of the product were as high as 96.8% and 95.7%,which are 15% and 16% higher than those of the corresponding reaction performed in aqueous phase ,To our best knowledge,this is the most satisfactory result obtained. 相似文献
6.
MA Beiyue YU JingkunSchool of Materials Metallurgy Northeastern University Shenyang China 《中国耐火材料》2007,16(4):17-20
Zircon (mesh size ≤ 44μm ) and carbon black (mesh size ≤30μm ) were used as the starting materials, weighed with re(zircon) : re(carbon black) of 100 : 20 and mixed fully. The specimens with the diameter of 20ram and length of 5ram were prepared by pressing at 100 MPa, then dried at 120℃ for 12h, put into a furnace with 1. 5L ·min^-1 argon gas and fired at 1450℃, 1500℃, 1550℃, 1600℃ and 1650℃ for 4h, respectively. The chemical composition, phase composition and microstructure of the specimens were studied by chemical analysis, X-ray diffraction and scanning electronic microscope, and the carbothermal reduction reaction process was discussed by thermodynamic analysis. The results showed that the ZrO2-SiC composite could be synthesized by carbothermal reduction reaction using zircon and carbon black as the starting materials in argon atmosphere. The composite with different composition was obtained by controlling the firing temperature and partial pressure of CO gas. The proper temperature to synthesize ZrO2-SiC composite was 1600℃ in this experiment. 相似文献
7.
Autoxidation of cycloalkanes(C5–C8) with molecular oxygen under catalyst-free and solvent-free conditions was conducted systematically for the first time, focusing on the autoxidation temperature and product distribution. The autoxidation of cyclopentane, cyclohexane, cycloheptane and cyclooctane occurs at 120 ℃,130 ℃, 120 ℃, and 105 ℃ respectively, with obvious oxidized products formation. At 140 ℃, 145 ℃, 130 ℃ and 125 ℃, acceptable yields of the oxidized products could be obtained for them, and the oxidized product distributions were investigated in detail. The autoxidation of cycloalkanes follows the pseudo-first-order kinetic model and the apparent activation energies(E_a) for the autoxidation of cyclopentane and cyclohexane are 159.76 kJ·mol~(-1) and 86.75 kJ·mol~(-1) respectively. This study can act as an important reference in screen of suitable reaction temperature and comparison of the performance of various catalysts in the catalytic oxidation of cycloalkanes in the attempt to enhance the oxidized product selectivity. 相似文献
8.
姚善泾 《中国化学工程学报》1999,7(1):47-55
In the established apparatus, the converaion ratios of cellaloee sulfation (X) under dif-ferent salfation conditlons were measured. The range of temperature was from -5℃ to 5℃, and the H2SO4 concentration was from 3.1 mol.L^-1 to 4.5 mol.L^-1. The experimental results were used for the establishment of the kinetic model for cellulose sulfation. With the model, X values and the yield of NaCS (Y) can be calculated, thus the reaction with respect to H2SO4 concentration is determined to be third order. 相似文献
9.
Asymmetric Synthesis of (-)-1-Trimethylsilyl-ethanol with Immobilized Saccharomyces Cerevisiae Cells in Water/Organic Solvent Diphasic System 下载免费PDF全文
Asymmetric synthesis of (-)-1-trimethylsilyl-ethanol with immobilized Saccharomyces cerevisiae cells in water/organic solvent biphasic system was studied. The effects of shake speed, hydrophobicity of organic solvent, volume ratio of water phase to organic phase, pH value of aqueous phase and reaction temperature on the initial reaction rate, maximum yield and enantiomeric excess (ee) of the product were systematically explored. All the above-mentioned factors had significant influence on the reaction. n-Hexane was found to be the best organic solvent for the reaction. The optimum shake speed, volume ratio of water phase to organic phase, pH value and reaction temperature were 150 r.min-1, 1/2, 8 and 30 ℃ respectively, under which the maximum yield and enantiomeric excess of the product were as high as 96.8% and 95.7%, which are 15% and 16% higher than those of the corresponding reaction performed in aqueous phase. To our best knowledge, this is the most satisfactory result obtained. 相似文献
10.
《中国耐火材料》2017,(3)
Carbon microspheres were firstly prepared using glucose(C_6H_(12)O_6) as the starting materials by hydrothermal carbonization. Then hollow ZrB_2 spheres were successfully synthesized using zirconium oxychloride( ZrClO_2·8H_2O),boric acid(H_3BO_3) by a combined sol-gel and boro/carbothermal reduction method,and the prepared carbon microspheres as the template. The effects of the reaction temperatures( 1200,1 300,1 400 and 1 500 ℃,respectively) and contents of carbon microspheres( n(C) n(ZrO_2+ B_2O_3) is 5. 0,5. 5,6. 0 and 6. 5,respectively) on the synthesis of hollow ZrB_2 spheres were studied. The prepared carbon microspheres have smooth surface and good hollow structure by hydrothermal nitridation. Increase of reaction temperature and excessive carbon microspheres can greatly promote the formation of hollow ZrB_2 spheres. The optimized reaction temperature and molar ratio of n( C)/n(ZrO_2+B_2O_3) were 1 500 ℃ and 6. 5,respectively. 相似文献
11.
12.
以特戊酸氯甲酯为原料,经过叠氮取代、环加成和威廉森合成反应,制得一种新型可传导质子的单体4-{[3-(三甲氧基硅烷基)丙氧基]甲基}-1H-1,2,3-三氮唑(Ⅲ)。采用正交实验设计和单因素实验考察了反应温度、反应时间、反应物料摩尔比和催化剂用量等因素对收率的影响,合成特戊酸叠氮甲酯(Ⅰ)的最佳工艺条件:n(叠氮钠)∶n(特戊酸氯甲酯)=1.5∶1,反应时间20 h,反应温度78℃;合成[4-(羟甲基)-1H-1,2,3-三唑-1-基]-特戊酸甲酯(Ⅱ)的最佳工艺条件:n(丙炔醇)∶n(Ⅰ)=1.3∶1,反应温度50℃,反应时间24 h,n(CuSO4.5H2O)∶n(抗坏血酸)∶n(Ⅰ)=0.02∶0.1∶1,在该条件下目标产物收率为63.9%。用FTIR、1HNMR和13CNMR对产物的结构进行了表征。 相似文献
13.
Zhen Lu Jie He Bogeng Guo Yulai Zhao Jingyu Cai Longqiang Xiao Linxi Hou 《中国化学工程学报》2022,43(3):110-115
The cycloaddition between CO2 and epoxides to produce cyclic carbonate is an attractive and efficiency pathway for the utilization of CO2 as C1 source. The development of catalyst to mediate cycloaddition between CO2 and epoxides at low temperature and pressure is still a challenge. Herein, a series of polypyrazoles with glass transition temperature (Tg) in the range of 42.3–52.5 ℃ were synthesized and served as catalyst to mediate the cycloaddition of CO2 and epoxides by the assistant of tetrabutylammonium bromide. The catalytic behaviors of polypyrazole on the model cycloaddition of CO2 to epichlorohydrin, including the reaction parameters optimization and versatility were investigated in detail, and excellent yield (99.9%) and selectivity (99%) were obtained under the optimized reaction conditions of 70 ℃ and 1.0 MPa for 6.0 h. Noteworthily, the polypyrazole acts as homogeneous catalyst during reaction (higher than Tg). And under room temperature, polypyrazoles can be easily separated and recovered, which is a promising feature of a heterogeneous catalyst. Furthermore, the reaction mechanism was proposed. The DFT calculation suggested that the formation of hydrogen bond between pyrazole and epoxide greatly reduced the energy barrier, which play an important role in promoting CO2 cycloaddition. 相似文献
14.
以硝基苯为起始原料,经还原生成苯基羟胺、再与4-吡啶甲醛反应生成硝酮、与4-乙烯基吡啶发生1,3-偶极环加成反应等3个步骤合成得到未见文献报道的新型四氢异噁唑啉化合物2-苯基-3,5-二(4-吡啶基)异噁唑啉。通过IR、1 HNMR、13 CNMR、HRMS等对该化合物的结构进行了表征。确定优化的1,3-偶极环加成反应条件为:反应温度75℃、溶剂为DMF。并对合成的新型四氢异噁唑啉化合物进行了生物活性测试,发现该化合物对10种病菌均有不同程度的抑制作用,尤其是对苹果轮纹的防效最高,达到了72.9%。表明,2-苯基-3,5-二(4-吡啶基)异啉啉具有一定的生物活性。 相似文献
15.
16.
(1S,5R,6R,7R)-6-羟甲基-7-羟基-2-氧杂双环[3.3.0]辛-3-酮(Ⅵ)是制备前列腺素的关键中间体。为了简化工艺条件,降低生产成本,以环戊二烯和二氯乙酰氯为原料,经环加成、还原和Baeyer-Villiger氧化3步反应制得2-氧杂双环[3.3.0]辛-6-烯-3-酮(Ⅳ),收率83.9%;经光学拆分后,与多聚甲醛经区域选择性Prins反应、粗产品不经分离,直接水解合成了Ⅵ,总收率22.0%。讨论了拆分剂、结晶溶剂对拆分Ⅳ的作用,确定了以R-(+)-苯乙胺为拆分剂,乙酸乙酯为结晶溶剂来拆分Ⅳ,拆分收率34.3%,[α]D20=-104.0°(c=1.0,MeOH),熔点:42~46℃。对Prins反应后水解产物的后处理工艺进行了优化,用氯仿重结晶代替柱分离来精制产品,收率76.5%,[α]D20=-45.0°(c=1.0,MeOH),熔点:117~119℃。目标产物用IR、MS、1HNMR进行了表征。 相似文献
17.
以1-苄基-2-氧代吲哚-3-亚氨基甲酸叔丁脂和4-取代(Z)-N-苯基苯甲酰氯为底物通过1,3-偶极环加成反应合成了9种目标产物。通过比较目标产物的产率,对反应溶剂、碱及其用量、温度等因素进行了优化,确定了最佳反应条件,即在25℃下以二氯甲烷为溶剂、三乙胺为碱,且n(Et3N)∶n(1-苄基-2-氧代吲哚-3-亚氨基甲酸叔丁脂)=2.0∶1.0时,目标化合物最高产率可达94.4%。将具有生物活性的三氮唑骨架引入到螺环氧化吲哚骨架中,为更好地发现具有生物活性的该类新化合物提供借鉴。 相似文献
18.
研究了手性双噁唑啉配体2,2-(2,2’-4(S)-苯基-4,5-二氢噁唑啉基)丙烷(5)与铜或锌的配合物对二苯基硝酮(8)与3-((E)-2-丁烯酰基)-1,3-噁唑烷-2-酮(6)和2,3-二氢呋喃(7)两种烯烃的环加成反应的催化效果。研究结果表明,双噁唑啉金属络合物对硝酮的环加成反应有较好的催化作用,表现在反应速度的提高和立体选择性的改变。比较而言,(5)与铜的配合物具有更好的催化作用。使用二氯亚砜作为氯化试剂对双噁唑啉(5)的合成方法进行了合理的改进,使产率由69.7%提高到89%。 相似文献
19.