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化妆品行业需要的植物提取液种类和数量正处于持续上升中。虽然传统的萃取方法能够满足这些需求,但同时它们也有局限性,并且很多时候会带来一些副作用。有机控制的植物微波萃取,再加上经过挑选的、纯净温和的溶剂,得到高质量的植物提取液产品,与传统萃取方法相比,它们含有更高的活性物质、更少的颜色成分和更少的沉淀。微波和植物细胞/结缔组织的接触时间非常短,因此在传统萃取方法中,可以避免发生由于缓慢浸泡而导致经常发生的氧化和活性成分降解等现象。微波萃取全程由HPTLC(高效薄层色谱)控制和分析,它是一个半连续的过程,由计算机控制。提取液不含任何防腐剂。 相似文献
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Leitner W 《Accounts of chemical research》2002,35(9):746-756
Carbon dioxide in its liquid or supercritical state (scCO(2)) has a prodigious potential as an environmentally benign reaction medium for sustainable chemical synthesis. Since the mid-1990s, rapidly increasing research efforts have shown that scCO(2) can replace conventional and potentially hazardous solvents in a wide range of processes. There is also increasing evidence that the application of scCO(2) can broaden the scope of catalytic synthetic methodologies. On the basis of the experience in our laboratories, this report analyzes the impact of scCO(2) on green organometallic catalysis. 相似文献
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<正>绿色科技已成为目前中国轮胎工业发展的主题和方向,低碳环保、节能降耗应引起全行业的高度关注。7月7~8日,中国橡胶工业协会轮胎分会在上海召开"2010中国轮胎技术论坛",旨在介绍适用于绿色轮胎的新型原辅材料、国际市场环保轮胎的 相似文献
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橘皮精油的主要成分D-柠檬烯具有较强的去污能力、天然的芳香味及抑菌功效。本论文以去污力为考察指标,通过单因素实验研究了橘皮精油,十二烷基磺酸钠及三乙醇胺的配比,制备出一种去污力较强的“绿色”环保型洗涤膏。其最佳配比为:D-柠檬烯:5.0%,十二烷基磺酸钠:13.6%,乙醇:4.4%,三乙醇胺:29.0%,氯化钠:2.2%,蒸馏水:45.8%。并对含橘皮精油的洗涤膏、市售洗涤剂的洗涤去污效粜进行了比较研究。测试结果表明,所制备的含橘皮精油洗涤膏与市售洗涤剂沈涤效果相当(去污比值约为1),且在洗涤树脂类污垢优于市售洗涤剂(去污比值为1.2)。 相似文献
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In view of global concerns regarding the environment and sustainable energy resources, there is a strong need for the discovery of new, green catalytic reactions. For this purpose, fresh approaches to catalytic design are desirable. In recent years, complexes based on "cooperating" ligands have exhibited remarkable catalytic activity. These ligands cooperate with the metal center by undergoing reversible structural changes in the processes of substrate activation and product formation. We have discovered a new mode of metal-ligand cooperation, involving aromatization-dearomatization of ligands. Pincer-type ligands based on pyridine or acridine exhibit such cooperation, leading to unusual bond activation processes and to novel, environmentally benign catalysis. Bond activation takes place with no formal change in the metal oxidation state, and so far the activation of H-H, C-H (sp(2) and sp(3)), O-H, and N-H bonds has been demonstrated. Using this approach, we have demonstrated a unique water splitting process, which involves consecutive thermal liberation of H(2) and light-induced liberation of O(2), using no sacrificial reagents, promoted by a pyridine-based pincer ruthenium complex. An acridine pincer complex displays unique "long-range" metal-ligand cooperation in the activation of H(2) and in reaction with ammonia. In this Account, we begin by providing an overview of the metal-ligand cooperation based on aromatization-dearomatization processes. We then describe a range of novel catalytic reactions that we developed guided by these new modes of metal-ligand cooperation. These reactions include the following: (1) acceptorless dehydrogenation of secondary alcohols to ketones, (2) acceptorless dehydrogenative coupling of alcohols to esters, (3) acylation of secondary alcohols by esters with dihydrogen liberation, (4) direct coupling of alcohols and amines to form amides and polyamides with liberation of dihydrogen, (5) coupling of esters and amines to form amides with H(2) liberation, (6) selective synthesis of imines from alcohols and amines, (6) facile catalytic hydrogenolysis of esters to alcohols, (7) hydrogenolysis of amides to alcohols and amines, (8) hydrogenation of ketones to secondary alcohols under mild hydrogen pressures, (9) direct conversion of alcohols to acetals and dihydrogen, and (10) selective synthesis of primary amines directly from alcohols and ammonia. These reactions are efficient, proceed under neutral conditions, and produce no waste, the only byproduct being molecular hydrogen and/or water, providing a foundation for new, highly atom economical, green synthetic processes. 相似文献
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Mohammad Shirmardi Amir Hossein Mahvi Bayram Hashemzadeh Abolfazl Naeimabadi Ghasem Hassani Mehdi Vosoughi Niri 《Korean Journal of Chemical Engineering》2013,30(8):1603-1608
Synthetic dyes are widely used by several industries to color their products. The discharge of colored wastewater into the hydrosphere causes serious environmental problems. We used functionalized multi wall carbon nanotubes as an adsorbent for the adsorption of cationic dye, malachite green, from aqueous solution. Based on information provided by the Iranian Research Institute of Petroleum Industry, carbon nanotubes are produced using a chemical vapor deposition (CVD) technique. These as-received MWCNTs were functionalized by acid treatment. The remaining dye concentration was read by UV-visible absorption spectroscopy at maximum adsorption wavelength. The effect of different operational parameters such as contact time, pH of solution, adsorbent dose and initial dye concentration were studied. The results showed that by increasing of contact time, pH and adsorbent dose the removal of dye increased, but by increasing initial dye concentration, the removal efficiency decreased. Adsorption isotherms and kinetics behavior of f-MWCNTs for removal of malachite green was analyzed, and fitted to various existing models. The experimental data were well correlated with the Langmuir isotherm with a maximum adsorption capacity (q m ) and regression coefficient (R2) of 142.85 mg/g and 0.997, respectively. The results of this study indicate that functionalized multi wall carbon nanotubes can be used as an effective adsorbent for the removal of dyes. 相似文献
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Sushmita Banerjee Yogesh C. Sharma 《Journal of Industrial and Engineering Chemistry》2013,19(4):1099-1105
A low cost activated carbon was synthesized from coconut coir and was applied for the removal of malachite green (MG) from its aqueous solutions. Characterization of the adsorbent was carried out and BET surface area of the adsorbent was found to be 205.27 m2/g. The process of removal of MG was better governed by second order kinetics with a rate constant of 0.21 g mg?1 min?1 at 323 K. The coefficient of mass transfer was found to be 3.70 × 10?5 cm s?1. The value of ΔG° was found to be negative indicating feasibility and spontaneity of the adsorption process. 相似文献
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A continuous cotton-like carbon nanotube fiber yarn, consisting of multiple threads of high purity double walled carbon nanotubes, was fabricated in a horizontal CVD gas flow reactor with water vapor densification by the direct chemical vapor deposition spinning process. The water vapor interaction leads to homogeneous shrinking of the CNT sock-like assembly in the gas flow. This allows well controlled continuous winding of the dense thread inside the reactor. The CNT yarn is quite thick (1-3 mm), has a highly porous structure (99%) while being mechanically strong and electrically conductive. The water vapor interaction leads to homogeneous oxidation of the CNTs, offering the yarn oxygen-functionalized surfaces. The unique structure and surface of the CNT yarn provide it multiple processing advantages and properties. It can be mechanically engineered into a dense yarn, infiltrated with polymers to form a composite and mixed with other yarns to form a blend, as demonstrated in this research. Therefore, this CNT yarn can be used as a "basic yarn" for various CNT based structural and functional applications. 相似文献
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Masamichi Akimoto Hidenao Yamada Kazuhisa Ohtaguchi Kozo Koide 《Journal of the American Oil Chemists' Society》1997,74(2):181-183
Focusing on CO2 fixation and α-linolenic acid (ALA) production, photoautotrophic cultivation of the green alga Chlamydomonas reinhardtii was investigated by using a culture medium of pH 6.8 under a 5 vol% CO2-enriched atmosphere. The optimum cultivation temperature and light intensity for growth were 25°C and 12 klux, respectively.
The cellular ALA content nearly doubled to 11.9 mg/g of dry cells when the concentration of culture medium was doubled. Simulation
of chemostat cultivation showed that the rate of CO2 fixation and ALA productivity per unit volume of culture medium could reach 1.01 kg CO2/(m3 · d) and 7.46 g ALA/(m3 · d), respectively, at a cell concentration of 0.57 kg cells/m3. 相似文献