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1.
Diisopropylidenated α-D-glucofuranose (1) was oxidated with CrO3-pyridine complex.Oxidated product and its hydrate were separated and were reduced together to synthesize diisopropylidenated α-D-allofuranose (3). The yield of 3 increased by 8% than that with only oxidated product as reduction substrate. Benzoylated derivative of 3 was selectively hydrolyzed and dimesylated to synthesize 3-O-benzoyl-1,2- O- isopropylidene-α-D-allofuranose (5) and its dimesylated deriva tive respectively. The overall yield of 5 from 1 was 36%. Each step and final products were anal yzed by 1H-NMR spectra and other methods. The experiments showed that the influence of acetic acid concentration on selective hydrolysis was obvious. The hydrolysis yield was 81.8%. Oxidation, reduction and other procedures were practical and had application potential. 相似文献
2.
使用碱性蛋白酶处理,考察摇床转速、酶解时间和加酶量对纳米级珍珠粉得率的影响．试验结果表明：10g珍珠粉加入50mL去离子水,在摇床转速为180r／rain、酶解时间为8h、酶用量为0．5g时,纳米级珍珠粉得率为95．2％．凯式定氮实验表明：酶解前后珍珠粉蛋白质的含量分别为24．132％和22．010％,酶解后仅相对减少了0．088． 相似文献
3.
The hydrolysate of waste sludge was used as the feedstock of biodiesel production, and its technological feasibility was investigated. Waste sludge, collected from No.3 Municipal Wastewater Treatment Plant of Xi＇an, was hydrolyzed in two parallel reactors firstly. Yeast was added into one reactor for bioaugmentation, and the other reactor without yeast was used as a control. Then an acid-catalyzed in situ esterification process was carried out to convert the hydrolysate to biodiesel. The results of hydrolysis showed that the reactor bioaugmented with yeast could promote hydrolysis compared with the control one because of an obvious variance in total suspended solid （TSS）, volatile suspended solid （VSS） and soluble chemical oxygen demand （SCOD）. Furthermore, gas chromatography （GC） analysis exhibited that the total volatile fatty acid （VFA） was low in the hydrolysate of bioaugmentation reactor; however, its yield of the fatty acid methyl esters （FAMEs） by in situ esterification was obviously higher when compared with the control one. Therefore, it may be inferred that the hydrolysate of bioaugmentation was mainly inclined to longer-chain fatty acid rather than to VFA. Anyway, an FAMEs yield of 9.24% （wt%） from dried sludge was attained after the 12-d bioaugmentation hydrolysis and succedent esterification. This value was not only higher than that of the control one but also higher than that reported in previous literature. The above results illuminated that it was feasible to produce biodiesel from the bioaugmented hydrolysate of waste sludge. 相似文献
4.
以对硝基苯胺为原料,经重氮化、成腙、环合、水解等四个步骤得到抗艾滋病药物地拉韦啶的关键中间体5-硝基-1H-吲哚-2-羧酸,产物结构经1HNMR以及元素分析得到确证,总收率为59.0%. 相似文献
5.
酶法水解植物蛋白 总被引：14，自引：0，他引：14
范恒君 《南宁职业技术学院学报》2000,5(3):57-61
以豆粕为原料 ,对蛋白酶水解植物蛋白的条件进行了研究。在酶解反应中 ,各因素对酶解作用的影响大小顺序是 :酶解时间 >p H值 >酶用量 >酶解温度。酶解反应的最适作用条件为 :温度 4 5℃、p H5.0和酶用量 30 0 0 u/ g。豆粕的水解度随时间的延长而增大 ,在4 5℃、p H5.0和 30 0 0 u/ g的条件下 ,水解豆粕 8h,水解产物的氮收率和水解度分别 55.4 6%和4 3.0 4 %。在同样条件下 ,水解油菜饼 ,水解产物氮收率和水解度分别为 57.59%和 4 4 .65%。 相似文献
6.
研究了以异硫氰酸苯酯、叠氮化钠、对二氯苄为主要原料,在微波辐射条件下合成1,4-二(1-苯基-1,2,3,4-四氮唑-5-硫代甲基)苯,并对影响反应因素进行了研究。结果表明:n(对二氯苄):n(1-苯基-5-巯基四氮唑)物质的量比为1:3,微波辐射时间为8 min,微波辐射功率为500 W,水用量50 mL时,反应条件最优化,产率可达90.5%。 相似文献
7.
以紫外线为诱变剂,用庆大霉素产生菌JY1-12为出发菌株,选育出性能优良的菌株JY3-5.经正交试验确定其最佳发酵培养基,研究了最佳发酵温度和初始pH值,使其摇瓶效价提高35.1%;30m3灌放大试验,比出发菌株效价提高19.2%. 相似文献
8.
以一次性竹筷为原料,采用预水解与硫酸盐蒸煮工艺相结合的方法制备浆粕,考察预水解条件并结合正交试验法对蒸煮条件进行筛选,同时利用光学显微镜观察纤维微观形貌。结果表明,较佳的制备条件为预水解时间30min,酸的质量分数1％,蒸煮时间110min,硫化度23％,绿氧用量0．3％,用碱量15％。在此实验条件下可制得得浆率45．68％,卡伯值74．8,聚合度307．03的浆粕。光学显微镜的观察结果表明,所制得的浆粕纤维表面结构受到破坏,纤维表面出现不均匀的裂纹与凹槽。 相似文献
9.
To optimize the hydrolysis conditions to prepare hydrolysates of jellyfish umbrella collagen with the highest hydroxyl radical scavenging activity, collagen extracted from jellyfish umbrella was hydrolyzed with trypsin, and response surface methodology (RSM) was applied. The optimum conditions obtained from experiments were pH 7.75, temperature (7) 48.77 ℃, and enzyme-to-substrate ratio ([E]/[S]) 3.50%. The analysis of variance in RSM showed that pH and [E]/[S] were important factors that significantly affected the process (P<0.05 and P<0.01, respectively). The hydrolysates of jellyfish umbrella collagen were fractionated by high performance liquid chromatography (HPLC), and three fractions (HF-1>3000 Da, 1000 Da相似文献
10.
以水解度为优化指标,利用单因素试验考察酶解温度、pH值、时间等因素对鱼蛋白水解的影响,利用中心组合试验方法优化酶的添加量和蛋白质浓度．结果表明,复合蛋白酶水解蓝圆够的最佳工艺条件为：加酶量2700U·g^-1蛋白、蛋白质浓度1．56％、水解温度60℃、反应体系pH7．5、反应时间8h．在此条件下,水解体系的氨基酸态氮含量达1．27mg·mL^-1,水解度为50．98％,挥发性盐基氮含量为0．032mg·mL^-1。 相似文献
11.
The effect of pressure on the hydrolysis rates and the degradation kinetics of environmentally persistent omethoate pesticide was studied. The results showed that the values of kobs increased and the values of activation volume (AV) decreased with increasing pressure. Among pH conditions (3.58, 6.01 and 8.5), pH 8.5 was found to be the unstable condition and its half-life was reduced from 263 min at 1 atm to 19.37 min at 10 atm. These results describe that high-pressure hydrolysis is a useful technique for the conversion of toxic organic phosphorus into inorganic phosphorus. 相似文献
12.
13.
任银 《鞍山师范学院学报》2013,(4):31-37
膳食纤维对人体尤其是儿童有重要的意义.利用酶碱法在西瓜籽仁及糯豆渣中提取水不溶性膳食纤维.西瓜籽仁最佳工艺条件:碱解温度为60℃,碱解pH为10,酶浓度为12 mg/mL,酶作用时间为50 min.在此基础上所得的水不溶性膳食纤维的产率为23.96%;糯豆渣最佳工艺条件:碱解时间10 h.碱解温度55℃,碱液浓度1.5%,料液比1∶7,在此基础上所得的水不溶性膳食纤维的产率为28.86%.得到的膳食纤维可用于乳制品、饮料及儿童食品. 相似文献
14.
以8个杂交籼稻品种(组合)为材料,在防雨棚内进行盆栽试验,研究了孕穗期干旱胁迫对水稻部分性状及产量的影响。结果表明:孕穗期干旱胁迫使水稻株高、穗长、一次分枝数、有效穗数、穗实粒数、生物产量、经济产量下降,生育期延长;其中新两优6号、新两优香4号、新两优6380、两优0293经济产量分别位于第一至第四位,产量分别为83.11、82.88、79.08、78.02g/盆,且较正常水分灌溉减产幅度仅为4.3%、5.0%、5.2%、10.3%。因此,新两优6号、新两优香4号、新两优6380、两优0293四个品种适宜在沿淮缺水地区推广种植。 相似文献
15.
将SO4^2-/TiO2-HZSM-5负载镧制备了新型催化剂SO4^2-/La2O3-TiO2-HZSM-5,以对羟基苯甲酸和丙醇的酯化反应为探针,考察了不同制备条件对催化剂性能的影响。结果表明：la^3＋浸渍浓度为0.07 mol/L,经110℃烘干后于500℃焙烧3h所得催化剂活性最好。对影响酯化反应的因素进行考察,最佳实验条件为n（醇）∶n（酸）=5∶1,反应时间4h,催化剂用量3.0%（总物料）,酯化率可达96.0%。且该催化剂具有良好的重复使用和再生能力,适宜合成对羟基苯甲酸酯。 相似文献
16.
以花生壳为原料,以SO42-/TiO2-Al2O3固体酸为水解催化剂制备乙酰丙酸,探讨了固体酸用量,水解时间,水解温度,液固比对乙酰丙酸得率的影响。研究结果表明,当固体酸用量3.5%、水解时间150 min、水解温度250℃、液固比21:1(L/mg)时为较优的制备工艺。在该工艺条件下,乙酰丙酸得率为12.35%。 相似文献
17.
以 2 ,6 二氯苯胺为原料 ,通过重氮化反应、取代反应、缩合反应与脱羧反应得到 3 氯 2 硝基甲苯的合成路线 ,确定了最佳反应条件 ,以 2 ,6 二氯苯胺为原料制取 2 ,6 二氯硝基苯 ,收率为 78.9% ;在N ,N 二甲基甲酰胺中以碳酸钾为催化剂 ,2 ,6 二氯硝基苯与氰基乙酸甲酯反应制取 2 氰基 2 (3′ 氯 2′ 硝基苯基 )乙酸甲酯 ,收率为 80 .2 % ;第三步通过水解反应获得 3 氯 2 硝基苯基乙酸 ,收率为 82 .6 % ;3 氯 2 硝基苯基乙酸通过脱羧反应得到最终产品 3 氯 2 硝基甲苯 ,产率为 72 .9% .采用红外光谱和核磁共振谱对产品进行了定性分析 相似文献
18.
HNCO hydrolysis performance in urea-water solution thermohydrolysis process with and without catalysts 总被引：1，自引：0，他引：1
Zhen-chao Chen Wei-juan Yang Jun-hu Zhou Hong-kun Lv Jian-zhong Liu Ke-fa Cen 《浙江大学学报(A卷英文版)》2010,11(11):849-856
The thermolysis of urea-water solution and its product, HNCO hydrolysis is investigated in a dual-reactor system. For the thermal decomposition below about 1073 K, the main products are ammonia (NH3) and isocyanic acid (HNCO) whereas at higher temperatures the oxidation processes take effect and the products include a low concentration of nitric oxide (NO) and nitrous oxide (N2O). The gas HNCO is quite stable and a high yield of HNCO is observed. The ratio of NH3 to HNCO increases from approximately 1.2 to 1.7 with the temperature. The chemical analysis shows that H radical is in favor of HNCO hydrolysis by instigating the reaction HNCO+H·→·NH2+CO and high temperature has positive effect on H radical. The hydrolysis of HNCO over an alumina catalyst made using a sol-gel process (designated as γ-Al2O3) is investigated. The conversion of HNCO is high even at the high space velocities (6×105 h-1) and low temperatures (393–673 K) in the tests with catalysts, which enhances HNCO hydrolysis and raises the ratio of NH3 to HNCO to approximately 100. The pure γ-Al2O3 shows a better catalytic performance than CuO/γ-Al2O3. The addition of CuO not only reduces the surface area but also decreases the Lewis acid sites which are recognized to have a positive effect on the catalytic activity. The apparent activation energy of the hydrolysis reaction amounts to about 25 kJ/mol in 393–473 K while 13 kJ/mol over 473 K. The overall hydrolysis reaction rate on catalysts is mainly determined by external and internal mass-transfer limitations. 相似文献
19.
Yong-liang Zhuang Xue Zhao Ba-fang Li 《Journal of Zhejiang University. Science. B》2009,10(8):572-579
To optimize the hydrolysis conditions to prepare hydrolysates of jellyfish umbrella collagen with the highest hydroxyl radical
scavenging activity, collagen extracted from jellyfish umbrella was hydrolyzed with trypsin, and response surface methodology
(RSM) was applied. The optimum conditions obtained from experiments were pH 7.75, temperature (T) 48.77 °C, and enzyme-to-substrate ratio ([E]/[S]) 3.50%. The analysis of variance in RSM showed that pH and [E]/[S] were
important factors that significantly affected the process (P<0.05 and P<0.01, respectively). The hydrolysates of jellyfish umbrella collagen were fractionated by high performance liquid chromatography
(HPLC), and three fractions (HF-1>3000 Da, 1000 Da<HF-2<3000 Da, and HF-3<1000 Da) were collected. The HF-2 fraction had the
highest hydroxyl radical scavenging activity with the highest yield compared with the other two fractions. Furthermore, HF-2
also showed the strongest Cu2+-chelating ability and the best tyrosinase-inhibitory activity.
Project (No. 2008BAD94B07) supported by the Hi-Tech Research and Development Program (863) of China 相似文献
20.
The urea nitrogen adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose （CDAC） and immobilized urease in gelatin membrane （IE）, was prepared. The cellulose, the dialdehyde cellulose （DAC） and the CDAC were characterized by scanning electronic microscope. The results indicate that the cellulose C2-C3 bond was broken under the oxidation of periodate and it was oxidated to DAC. The DAC was coated with chitosan and the CDAC was obtained. The adsorption of urea nitrogen onto the adsorbent in Na2HPO4-NaH2PO4 buffer solution was studied in batch system. The effects of the experiment parameters, including degree of oxidation of CDAC, initial urea nitrogen concentration, pH and temperature, on the adsorption capacity of urea nitrogen onto the adsorbent at CDAC/IE weight ratio 10：1 were investigated. The results indicate that these parameters affected significantly the adsorption capacity. The adsorption capacity of urea nitrogen onto the adsorbent was 36.7 mg/g at the degree of oxidation of CDAC 88%, initial urea nitrogen concentration 600 mg/L, pH 7.4 and temperature 37℃. 相似文献