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麦芽糖加氢制麦芽糖醇的实验研究 总被引:1,自引:0,他引:1
采用三元Raney Ni合金催化剂进行麦芽糖加氢,考察了温度、压力、pH值、剂糖比和反应时间等因素对反应的影响。结果表明:使用三元Raney Ni催化剂RTH-311进行麦芽糖加氢,当反应温度为120~130℃、压力为9~10MPa、pH值为8·0、剂糖质量比为5%、反应时间为120~150min时,转化率可达98·8%以上。 相似文献
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新型合金催化剂用于木糖加氢制木糖醇的研究 总被引:1,自引:0,他引:1
采用三元Raney Ni合金催化剂进行木糖加氢,考察了温度、压力、pH值、剂糖比和反应时间等因素对加氢反应的影响,并与其它Raney Ni类催化剂进行了对比。结果表明,使用Raney Ni催化剂RTH-311进行木糖加氢,当反应温度为130-140℃、压力为8-10MPa、pH值为6-7、剂糖质量比为2%、反应时间为90~120min时,转化率可达100%,产品色度好。RTH-311催化剂的木糖加氢活性好于其它类催化剂,重复使用时,也可保持较高活性。 相似文献
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采用大连通用化工有限公司研制的三元Raney Ni合金催化剂进行木糖加氢,考察了温度、压力、pH值、剂糖比和反应时间等因素对加氢反应的影响,并与其它Raney Ni类催化剂进行了对比.结果表明,使用大连三元Raney Ni催化剂RTH-311进行木糖加氢,当反应温度为130~140℃、压力为8~10MPa、pH值为6~7、剂糖质量比为2%、反应时间为90~120min时,转化率可达100%,产品色度好.RTH-311催化剂的木糖加氢活性好于其它类催化剂,重复使用时,也可保持较高活性. 相似文献
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以Ni/硅藻土为催化剂,研究了2,4-二硝基甲苯(2,4-DNT)在2,4-二氨基甲苯(2,4-TDA)和乙醇混合溶剂中加氢生成2,4-TDA的反应历程,考察了反应温度、反应时间和氢气压力等条件对2,4-DNT加氢的影响。结果表明,反应温度和反应时间是影响2,4-DNT加氢的主要因素,最佳反应条件为:反应温度120~130℃、氢气压力2.5~3.0MPa,反应时间140min。 相似文献
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SRNA-4非晶态合金催化双环戊二烯液相加氢反应研究 总被引:3,自引:0,他引:3
采用SRNA-4非晶态合金催化剂对双环戊二烯(DCPD)进行了加氢反应考察,研究了搅拌速度、温度、压力和催化剂浓度各条件对双环戊二烯加氢反应的影响.结果表明DCPD加氢反应为连串反应,中间产物主要为9,10-二氢双环戊二烯(9,10-DHDCPD)和少量1,2-二氢双环戊二烯(1,2-DHDCPD);DCPD易于加氢生成中间产物9,10-DHDCPD,其继续加氢为四氢双环戊二烯(endo-THDCPD)需要较为剧烈的条件.DCPD加氢过程选用两段法,第一段为温度110℃,第二段为130℃,压力均为1.5MPa,催化剂浓度1.18%.非晶态合金(催化剂)对DCPD的加氢反应活性明显高于Raney Ni,可进行1、2位加氢反应生成1,2-DHDCPD,并且催化剂用量少,反应温度和反应压力低,反应时间短,生成副产物少. 相似文献
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非晶态CoNiB能催化糠醛液相加氢制糠醇 总被引:1,自引:0,他引:1
采用化学还原法制备了CoNiB非晶态合金催化剂,并用于糠醛液相加氢制糠醇反应。考察了Ni/Co摩尔比,NaBH4滴加速率等催化剂制备条件对催化性能的影响,以及反应压力、反应时间、反应温度等反应条件对糠醛转化率和糠醇选择性的影响。结果表明:最佳的催化剂制备条件是Ni/Co摩尔比为5/5,NaBH;滴加速率为2.6mL·min2;最佳的反应条件为反应压力2MPa,反应时间3h,反应温度80℃。在此条件下糠醛的转化率为46.2%,糠醇的选择性为90.4%。 相似文献
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The drying of barley malt was studied in a batch spouted-bed dryer using three inlet air temperatures (60, 80 and 90°C) and three initial masses of malt (25, 30 and 35 kg). One of the conclusions was that the drying can be conducted at higher temperatures than in the classical equipment. A general correlation was obtained through the use of reduced moisture and reduced time. A mathematical model which assumes only an external resistance of diffusion or heat transfer does not apply. Also, the model based on internal water diffusion does not predict the results. A new semi-empirical model based on semi-permeable membranes has been proposed. A method of using batch laboratory drying data to predict the performance of continuous spouted-bed driers has been outlined. 相似文献
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Claver IP Zhang H Li Q Zhu K Zhou H 《International journal of molecular sciences》2010,11(8):3002-3015
Starches were isolated from soaked and malted sorghum and studied to understand their physicochemical and functional properties. The swelling power (SP) and the water solubility index (WSI) of both starches were nearly similar at temperatures below 50 °C, but at more than 50 °C, the starch isolated from malted sorghum showed lower SP and high WSI than those isolated from raw and soaked sorghum. The pasting properties of starches determined by rapid visco-analyzer (RVA) showed that malted sorghum starch had a lower viscosity peak value (86 BU/RVU) than raw sorghum starch (454 BU/RVU). For both sorghum, X-ray diffractograms exhibited an A-type diffraction pattern, typical of cereal starches and the relative degrees of crystallinity ranged from 9.62 to 15.50%. Differential scanning calorimetry (DSC) revealed that raw sorghum starch showed an endotherm with a peak temperature (Tp) at 78.06 °C and gelatinization enthalpies of 2.83 J/g whereas five-day malted sorghum starch had a Tp at 47.22 °C and gelatinization enthalpies of 2.06 J/g. Storage modulus (G') and loss modulus (G″) of all starch suspensions increased steeply to a maximum at 70 °C and then decreased with continuous heating. The structural analysis of malted sorghum starch showed porosity on the granule's surface susceptible to the amylolysis. The results showed that physicochemical and functional properties of sorghum starches are influenced by soaking and malting methods. 相似文献
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Chemical biology of the sugar code 总被引:10,自引:0,他引:10
Gabius HJ Siebert HC André S Jiménez-Barbero J Rüdiger H 《Chembiochem : a European journal of chemical biology》2004,5(6):740-764
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利用糖醇生产低级多元醇可以减少对石油资源的依赖,是可再生资源利用的一个重要研究方向。本文综述了利用糖醇为原料催化氢解制备低级多元醇的研究成果,氢解糖醇可以高选择性得到乙二醇、丙三醇和1,2-丙二醇的混合物。重点介绍了糖醇催化氢解的Retro-aldol、 Retro-Michael反应机理和铜系、镍系、贵金属催化剂,并对糖醇催化氢解的发展前景做了展望,提出开发更为高效稳定的催化体系、降低催化剂制备成本和优化工艺条件将是未来研究工作的重点。 相似文献
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采用紫外分光光度法,以邻苯二胺作显色剂,波长334 nm,测定富硒麦芽中微量元素硒的含量。结果表明,线性方程为A=0.207 78c+0.003 69,相关系数r=0.999 86;平均加标回收率为98.04%,RSD=4.4%;方法的精密度(RSD=2.7%)、重现性(RSD=1.4%)和稳定性(RSD=0.80%)均较好;富硒麦芽中硒的含量为0.6~42.1μg/g。该方法具有操作简单,测定快速,灵敏度高,毒性较小等优点,适用于测定麦芽中微量硒的含量。 相似文献