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排序方式: 共有209条查询结果,搜索用时 615 毫秒
1.
催化精馏合成N-异丙基苯胺 总被引:3,自引:2,他引:1
在Joback基团贡献法估算反应的G ibbs函数的基础上,得到了异丙醇与苯胺合成N-异丙基苯胺的平衡常数与反应温度的关系式。研究了回流比、异丙醇与苯胺的摩尔比、塔釜操作温度、苯胺进料口位置距塔顶的距离对异丙醇与苯胺催化精馏合成N-异丙基苯胺的影响,确定了适宜的工艺条件:回流比2.5~3.5、异丙醇与苯胺的摩尔比1.5、塔釜操作温度223℃、苯胺进料口位置距塔顶300~400mm。在优化条件下,苯胺的转化率可达到99%,N-异丙基苯胺的选择性可达到99.5%,N-异丙基苯胺的质量分数可稳定在98.8%以上。 相似文献
2.
Luciana M. Rodriguez María B. Fernández Ethel E. Pérez Guillermo H. Crapiste 《European Journal of Lipid Science and Technology》2021,123(1):2000132
The main goal of this work is to evaluate the extraction of sunflower oil from enzyme-treated collets using ethanol and isopropanol (IPA) as solvents. The sunflower collets are pretreated with the multienzyme complex Viscozyme L prior to solvent extraction by the Soxhlet method. The influence of the moisture content of the collets, pretreatment, processing time, and solvent type on the amount of total extracted material and the oil extraction efficiency is studied. Some quality parameters such as phospholipid content of the oil and chlorogenic acid content of the residual meal are also analyzed. At low moisture content (7%) the solvents exhibit similar oil extraction ability (98–99%), but with increasing moisture the extraction efficiency of ethanol decreases to about 85%, while no significant differences are observed for IPA. The enzymatic treatment increases the extraction efficiency for all times, especially for ethanol. It is observed that IPA is more efficient in the extraction compared to ethanol, and the amount of nonlipid material is reduced by ≈70%. In addition, the oil extracted with IPA have lower phospholipid content and the residual meal presents a higher chlorogenic acid content. Practical Applications:This work would contribute toward the use of green solvents in the extraction of sunflower oil from collets. Ethanol and isopropanol, used as solvents, present attractive advantages, including low toxicity, good operational security, as well as being obtained from a renewable source. The obtained data provide up-to-date information on the use of these alcohols in the extraction of sunflower oil from collets and the influence of operating conditions, such as moisture content, enzymatic pretreatment of the collets, and the extraction time. Information about oil and meal quality is also reported. 相似文献
3.
采用顶空—固相微萃取—气相色谱联用技术测定了氨苄西林钠中丙酮和异丙醇残留量。使用100μmPDMS萃取头,顶空平衡温度为60℃,萃取时间为40 min,2m×3 mm(i.d.)不锈钢色谱柱、内填充10%丁二酸乙二醇聚酯/202酸洗红色担体。外标法定量,丙酮测定结果的相对标准偏差(RSD)为0.43%,在0.1μg/g~20μg/g范围时,色谱峰面积与质量浓度之间呈良好线性关系,相关系数(R2)为0.979 9,回收率为97.8%~103%;异丙醇测定结果的相对标准偏差(RSD)为0.88%,在0.2μg/g~20μg/g范围时,色谱峰面积与质量浓度之间呈良好线性关系,相关系数(R2)为0.980 2,回收率为95.7%~101%。 相似文献
4.
5.
Ethanol vapor deactivation of gossypol in cottonseed meal 总被引:3,自引:0,他引:3
R. J. Hron Sr. P. J. Wan M. S. Kuk 《Journal of the American Oil Chemists' Society》1996,73(10):1337-1339
Most cottonseed cultivars contain gossypol, a polyphenolic antinutritional compound. “Free” gossypol is a physiologically
active form of gossypol, which is toxic to young- and nonruminant animals. To utilize solvent-extracted cottonseed meal as
a general feed, gossypol must be either removed or deactivated to a minimum level specified for each class of animal. Normally,
deactivation is carried out prior to oil extraction; however, the desired level of deactivation is not always attained. A
new supplemental method of deactivation has been found by using either ethanol or isopropanol vapors on solventextracted meal.
In a bench-top set-up, ethanol vapor reduced free gossypol from 0.115 to 0.053%, and a further reduction to 0.026% has been
observed with the addition of ferrous sulfate. The supplemental deactivation method can, in most cases, reduce free gossypol
to significantly safer levels for feeding, thus increasing utility, and possibly demand, for cottonseed meal as a general
animal feed protein source.
Presented in part at the AOCS Annual Meeting, Atlanta, GA, May 8–12, 1994. 相似文献
6.
Dennis J. O’Brien Gerard E. Senske 《Journal of the American Oil Chemists' Society》1994,71(9):947-950
Utilization of lipids containing eicosapentaenoic acid (EPA) produced by microorganisms requires processes for their efficient
recovery from microbial cells. Recovery of EPA from mycelia of the fungusPythium irregulare by solvent extraction with hexane-isopropanol (HIP) in a pilot-plant colloid mill was investigated. Extraction efficiencies
of 96% for lipid and EPA were achieved with a 3∶2 (vol/vol) HIP mixture by milling wet, filtered mycelia for 5 min at a solvent/dry
solids ratio of 100 L/kg. The process yielded a crude extract that contained up to 96% lipid and an EPA content as high as
24% (with no selectivity for EPA). 相似文献
7.
Thomas Onfroy Guillaume Clet Saeed B. Bukallah David M. Hercules Marwan Houalla 《Catalysis Letters》2003,89(1-2):15-19
A series of NbO
x
/ZrO2 catalysts containing up to 2.67wt Nb (ca. 80 nominal surface coverage) was prepared by incipient wetness impregnation from niobium oxalate and oxalic acid solution. The structure of the catalysts was monitored by X-ray diffraction and Raman spectroscopy. The results indicated the presence of a surface Nb phase. No evidence for the formation of crystalline Nb2O5 species was found. The development of the acidity as a function of Nb loading was monitored by adsorption of a basic probe molecule followed by infrared spectroscopy. The results indicated the appearance of Brnsted acid sites for a threshold of Nb loading. The abundance of Brnsted acid sites correlated well with the isopropanol dehydration activity. The overall behavior was very similar to that reported earlier for the WO
x
/ZrO2 system. 相似文献
8.
C. Adhikari A. Proctor G. D. Blyholder 《Journal of the American Oil Chemists' Society》1995,72(3):337-341
Diffuse reflectance Fourier transform infrared spectroscopy was used to study the mode of adsorption of phosphatidylcholine
(PC) in hexane onto silicic acid (SA). PC adsorption was mainly through the charged phosphate group with minimal binding through
the ester carbonyl. When the SA surface with adsorbed PC is washed with hexane, containing a small concentration of isopropanol,
the desorbed PC is recovered without structural change, i.e., there is no evidence of PC hydrolysis in the adsorption process.
Adsorbent misture probably promotes PC adsorption due to the increased availability of surface water hydroxyl groups for interaction
with the PC phosphate groups. Isopropanol promoted PC binding by destabilizing PC reverse miscelles in solution, thus promoting
its adsorption. 相似文献
9.
The series of compounds La2–xSrxNiO4±y (0.0 x 1.0) crystallising in tetragonal K2NiF4 structure were prepared and catalytic activity have been investigated using isopropanol decomposition as model reaction. All the catalyst compositions catalyse only the dehydrogenation of isopropanol reaction. The composition La1.5Sr0.5NiO4 showed high activity compared to other compositions in the series. The composition is unique not only in catalytic property but also in other physical properties like structural characteristics, electrical resistivity and metal to semiconductor transition. 相似文献
10.
异丙醇-异丙醚形成二元共沸物,一般精馏方法很难分离.利用化工过程软件Aspen Plus,在异丙醇和异丙醚产物的摩尔分数达到0.999的条件下,以乙二醇为溶剂的萃取精馏流程和热集成变压精馏流程对异丙醇-异丙醚混合物分离进行模拟.以全年总费用最低为目标,确定萃取精馏流程两塔的理论板数、进料位置和溶剂进料位置以及热集成变压精馏流程的高压塔操作压力,两塔的理论板数,进料位置,得到两种流程的最优操作条件.从模拟结果可知,对于异丙醇-异丙醚混合物的分离,热集成变压精馏所需的全年总费用更低,比萃取精馏的全年总费用降低了10.86%.对于该混合物,热集成变压精馏流程要优于萃取精馏流程. 相似文献