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中位-四l-(对十六酰氧基)苯基卟啉的合成与表征 总被引:7,自引:2,他引:5
本文以四-(对羟基苯基)卟啉与十六酰氯为原料,通过酯化反应合成了中位-四-(对十六酰氧基苯基)卟啉,采用红外光谱监测了反应进程,以硅胶为固定相,氯仿为洗脱剂采用柱层析方法对反应产物进行了分离与提纯。最后用元素分析,紫外可见光谱,红外光声光谱,核磁共振氢谱,摩尔电导等手段对合成产物进行了结构表征,对主要的紫外光谱,红外光谱及核磁共振氢谱吸收带进行了经验归属,初步确定了合成产物的结构。 相似文献
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黄芩素的分离纯化与结构表征 总被引:2,自引:0,他引:2
以聚酰胺为柱层析吸附剂,以乙醇-氯仿混合溶剂梯度洗脱,从中药黄芩的甲醇提取液中分离出有效成分黄芩素的粗品。 通过对有效成分进行重结晶等纯化处理,得到了一种黄色短棱柱晶状产物。 利用红外光谱(FTIR)、紫外-可见光谱(UV-Vis)、质谱(MS)、氢谱(1H-NMR)及碳谱(13C-NMR)等分析测试手段,对产物的组成和结构进行了表征。 红外光谱测定结果表明,产物的结构中含有共轭芳香体系和单取代苯;紫外-可见光谱和质谱表明,产物为黄酮而非黄酮苷化合物,A环上含有三个酚羟基, B环无羟基和其他基团取代;核磁共振氢谱及碳谱表明,产物的结构中含15个碳原子, 三组羟基质子。 同时,文章还对所有1H-NMR和13C-NMR信号进行了归属,对FTIR光谱特征吸收峰所对应的官能团及其振动形式进行了指认,给出了化合物及碎片离子在质谱中的裂解方式,最终将黄色短棱柱晶状产物鉴定为5,6,7-三羟基黄酮,即黄芩素,分子式为C15H10O5。 相似文献
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以L-色氨酸甲酯盐酸盐为起始原料,经过Pictet-Spengler反应,再通过结晶诱导不对称转化(CIAT)过程,最后用饱和碳酸钠溶液脱除盐酸后高效选择性的得到1-取代-1,2,3,4-四氢-9H-吡啶并[3,4-b]吲哚-3-羧酸甲酯,目标产物通过重结晶或者柱层析方法纯化,所有化合物的结构均经元素分析,IR,1H NMR,13C NMR确证. 相似文献
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巢湖蓝藻藻蓝蛋白纯化过程中紫外-可见吸收光谱特征分析 总被引:2,自引:0,他引:2
以巢湖新鲜蓝藻为处理对象,采用冻融破壁方法获得藻蓝蛋白粗提液,采用两步盐析结合两步柱层析的方法纯化藻蓝蛋白粗提液,以最终获得试剂级藻蓝蛋白。分别将纯化过程中各阶段得到的藻蓝蛋白溶液和杂质液进行紫外-可见光谱扫描。经光谱扫描发现:藻蓝蛋白溶液经一步盐析、二步盐析、一步柱层析和二步柱层析的四步纯化实验过程中,在250~300 nm吸收谱带中,吸收峰从260 nm红移至280 nm;在500~700 nm吸收谱带中,吸收峰从617 nm红移至620 nm,并表现为最大特征吸收峰。对四步纯化工艺过程中分别得到的不同杂质液同样进行250~700 nm全波段光谱扫描,分析判断得出:一步盐析杂质液成分主要含有杂蛋白和部分藻蓝蛋白;二步盐析的杂质液中主要成分为核酸和维生素类物质;一步柱层析分离的先出组分主要成分为藻红蛋白;二步柱层析分离的后出组分主要成分为别藻蓝蛋白。经四步纯化工艺后,最终得到了纯度大于4以上的试剂级藻蓝蛋白。由此可见,两步盐析的工艺主要作用在于去除杂蛋白、核酸和维生素类物质;两步柱层析工艺主要作用在于分离出和藻蓝蛋白性质接近的藻红蛋白和别藻蓝蛋白。 相似文献
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柱层析色谱分离性能优良的新型塑料脱模剂,纯化后得一主要未知组分。用元素分析、红外光谱、核磁共振氢谱研究其结构特征,对其盐酸酸化前后红外光谱吸收峰及核磁带进行了归属分析并确定结构。结果表明,该组分为一表面活性剂N,N-二羟乙基十二烷基胺。这为新型脱模剂的产品开发提供了依据。 相似文献
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为了明确原油降粘剂的主要组分,采取蒸馏、溶解一沉淀法及柱色谱法对原油降粘剂进行分离与纯化,用红外光谱法对其主要组分官能团的结构进行了鉴定,推断其主要组分是丙烯酸乙酯/甲基丙烯酸甲酯/丙烯酸三元共聚物,用核磁共振氢谱及质谱进行了结构确认及定量分析,共聚物中3种单体:丙烯酸乙酯、甲基丙烯酸甲酯、丙烯酸的摩尔数比为37.1:25.8:37.1;重量百分比为41.1:28.8:29.8.用红外光谱对甲醇溶液部分进行了结构分析,结果表明,非离子表面活性剂为聚氧乙烯醚,分子量范围是800~1 600,阴离子表面活性剂为烷基苯磺酸钠,其余为助剂和水. 相似文献
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Yamila Garro Linck M. H. M. Killner E. Danieli B. Blümich 《Applied magnetic resonance》2013,44(1-2):41-53
Biodiesel produced mainly by the base-catalyzed transesterification of vegetable oils or animal fats with a short chain alcohol, has become an attractive alternative to petroleum-based diesel fuel. Even though high-field 1H nuclear magnetic resonance (NMR) is a reliable method for biodiesel quality control, it is restricted by its poor mobility and expensive superconducting coils. As an alternative, this study presents a mobile low-field 1H NMR spectrometer for the analysis of biodiesel samples derived from different feedstock oils. The low-field 1H NMR spectra of all the compounds coexisting in a typical transesterification reaction such as rapeseed oil, rapeseed biodiesel, methanol, and glycerol, could be clearly differentiated. Field-dependent characteristic parameters such as relaxation times are provided. The degree of saturation of the different biofuels samples could be reliably estimated via integration of the resolved signals of the spectra. The obtained results agreed well with those measured at high-field 1H NMR. Since this compositional information is directly related to the biodiesel properties, the presented mobile low-field 1H NMR device built from permanent magnets arrayed in a Halbach geometry, constitutes an excellent alternative tool for biodiesel quality control. 相似文献
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Triglyceride transesterification for biodiesel production is a model reaction which is used to compare the conversion efficiency, yield, reaction time, energy consumption, scalability and cost estimation of different reactor technology and energy source. This work describes an efficient, fast and cost-effective procedure for biodiesel preparation using a rotating generator of hydrodynamic cavitation (HC). The base-catalyzed transesterification (methanol/sodium hydroxide) has been carried out using refined and bleached palm oil and waste vegetable cooking oil. The novel HC unit is a continuous rotor-stator type reactor in which reagents are directly fed into the controlled cavitation chamber. The high-speed rotation of the reactor creates micron-sized droplets of the immiscible reacting mixture leading to outstanding mass and heat transfer and enhancing the kinetics of the transesterification reaction which completes much more quickly than traditional methods. All the biodiesel samples obtained respect the ASTM standard and present fatty acid methyl ester contents of >99% m/m in both feedstocks. The electrical energy consumption of the HC reactor is 0.030 kW h per L of produced crude biodiesel, making this innovative technology really quite competitive. The reactor can be easily scaled-up, from producing a few hundred to thousands of liters of biodiesel per hour while avoiding the risk of orifices clogging with oil impurities, which may occur in conventional HC reactors. Furthermore it requires minimal installation space due to its compact design, which enhances overall security. 相似文献
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Ultrasonication used for the production of fatty acid methyl ester from non-edible vegetable oil using immobilized lipase (Chromobacterium viscosum) as a catalyst from Enterobacter aerogenes to make the process fully ecologically and environmental friendly. The optimal conditions for biodiesel production is the molar ratio oil to methanol 1:4, catalyst concentration 5 wt.% of oil, reaction time 30 min, ultrasonic amplitude 50% (100 W/m(3)) and cycle 0.7s. ultrasonication reduce the reaction time comparing to the conventional batch process. The purity and conversion of the biodiesel was 84.5±0.5 analyzed by reversed phase HPLC. 相似文献
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Two-stage continuous production process for fatty acid methyl ester (FAME) from crude palm oil was performed using the rotor–stator hydrocavitation reactor. The novel ABS filament printed rotor having spherical holes on the surface of the rotor which is an efficient, fast and cost-effective procedure, was installed in the stainless steel stator of hydrosonic reactor. The 3D printed hydrosonic reactor was used to treat the FFA-rich in MCPO by esterification and followed by transesterification to produce the methyl ester. The optimum conditions of both esterification and transesterification processes were determined using the response surface methodology (RSM). For the 1st step esterification, the conditions of methanol 17.7 vol%, sulfuric acid 2.9 vol%, 3000 rpm rotor speed, hole’s diameter and depth 4 and 6 mm, and 25 L/h MCPO, were used for decreasing the FFA from 11.456 to 1.028 wt%. For the 2nd step, transesterification was employed with the optimal condition of 28.6 vol% methanol, 6.2 g/L of potassium hydroxide, 3000 rpm rotor speed, the dimension of the spherical holes on the rotor’s surface having diameter of 6.4 mm and 6.2 mm in depth, and esterified oil flow rate 25 L/h, for producing the methyl ester to over 99.163 wt%. Moreover, the purified biodiesel yields and the average energy consumption for the entire two-stage continuous process between hydrosonic and ultrasonic clamp reactors were compared. The results of purified methyl ester clearly indicate that the methyl esters of 99.163 wt% and 97.814 wt% were achieved from hydrosonic and ultrasonic clamp reactors, respectively, under the same optimized conditions. The maximum yields of purified biodiesel were 97.51 vol% and 88.69 vol% using hydrosonic and ultrasonic clamp reactors, respectively. The average energy consumption for the entire continuous two-stage process for both hydrosonic and ultrasonic clamp reactors were 0.049 and 0.056 kW h/L, respectively. For practical industrial processes, stainless steel rotors inside the stator was manufactured by CNC machine, which was also verified under the optimum conditions. The results showed that 1.07 wt% FFA and 99.221 wt% methyl ester of were obtained from first step and second step, respectively. 相似文献
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本文以硝酸银和磷钨酸为原料制备了系列银改性磷钨酸催化剂AgxH3-xPW12O40(x=1、2、3,x表示AgNO3与磷钨酸的物质的量之比),并利用傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、热重量分析-导数热重量分析(TGA-DTG)和固体核磁共振结合探针分子(31P-TMPO MAS-NMR)技术对它们的结构、稳定性及酸性进行了表征;同时考察了甲醇/大豆油的物质的量之比、催化剂用量、反应温度和反应时间等因素对磷钨酸银催化酯交换反应的影响.研究结果表明,Ag2HPW12O40催化剂具有最好的催化酯交换反应活性和重复使用性能,其结构中的Brønsted酸中心与Lewis酸中心之间的协同效应是使其具有高催化性能的原因.以Ag2HPW12O40为催化剂,在甲醇/大豆油的物质的量之比为32/1、催化剂用量为6 wt.%、反应温度为150℃、反应时间为20 h条件下,生物柴油产率可达96.4%. 相似文献
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V. A. Yakovlev S. G. Zavarukhin V. T. Kuzavov S. V. Stebnovskii N. V. Malykh L. I. Mal’tsev V. N. Parmon 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(2):227-234
The action of ultrasonic and hydrodynamic cavitation on the cracking of organic compounds of various natures (linear alkanes
(octane, undecane, and hexadecane), carboxylic acids (decanoic and oleic acids), alcohols (decanol), and esters (ethyl caprate))
and transesterification of rapeseed oil and methanol and ethanol was studied. An analysis of hydrocarbon transformation products
by gas chromatography, high-performance liquid chromatography, NMR, and chromato-mass spectrometry showed that cavitation
treatment of any class of organic compounds of those mentioned above resulted in transformations no more than 1.1% deep. In
experiments with transesterification of rapeseed oil and methanol and ethanol without a catalyst under the action of cavitation,
the yield of fatty acid esters did not exceed 2.1 mol %. The energy efficiency of the cavitation apparatus was estimated at
0.002% for endothermic cracking of alkanes. The data obtained led us to conclude that the use of cavitation directly for performing
cracking of various organic compounds and noncatalytic transesterification of vegetable oils was ineffective. 相似文献
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Biodiesel was obtained by transesterification of Jatropha curcus oil with anhydrous methanol, ethanol, and various mixtures of methanol/ethanol system. The present research work ultrasonic assisted transesterification of J. curcus oil was carried out in the presence of various mixtures of methanol/ethanol system and potassium hydroxide (KOH) as a catalyst, keeping the molar ratio of oil to alcohol 1:6. The methodology allows for the reaction to be run under atmospheric conditions. The ethanomethanolysis and ultrasonic mixing promote the rate of transesterification reaction due to the better solubility of oil with ethanol in reaction mixture and obtained methyl esters as well as ethyl esters. 相似文献