نتایج جستجو برای: green synthesis
تعداد نتایج: 539822 فیلتر نتایج به سال:
decatungstodivanadogermanic acid (h6gew10v2o40.22h2o) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1h)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. this method provides an efficient and much improved modification of the original biginelli reaction...
an efficient one-pot condensation for the synthesis of 1,8-dioxo-octahydroxanthene is achieved through a condensation of aryl aldehydes and 5,5-dimethyl-1,3-cyclohexandione in the presence of nbs. this method enjoys several advantages such as low cost, simple work up procedure and safe reaction condition. in addition, water was chosen as a green solvent.
cuo-ceo2 nanocomposite is reported as a green and highly efficient recyclable catalyst for the multicomponent synthesis of 3,4-dihydropyrimidin-2(1h)-ones/thiones under solvent-free conditions. the catalyst was synthesized by co-precipitation method and characterized by xrd, bet specific surface area, fesem and eds analysis.
in this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1h)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using al-mcm-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. the advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions.
4-dodecylbenzenesulfonic acid (dbsa) has been shown to be an efficient, mild, green, stable and chemoselective brønsted acid catalyst for the synthesis of 1, 1-diacetates (acylals) of aldehydes under solvent-free conditions. the mild condition, eco-friendly, excellent yields, short reaction times and using an easily available, inexpensive and reusable catalyst are important features of this met...
Nano sulfated titania was tested as solid acid heterogeneous catalyst for the synthesis of 4-(Trifluoromethyl) coumarin and coumarin derivatives under solvent-free condition. Factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents. This nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. The prepared sulfated titania s...
The development of the concepts for “Green Chemistry” and main principles this field are reviewed. Examples application these in different areas chemistry included. frequently used alternative solvents (green – water, PEG, perfluorinated solvents, supercritical liquids) preparative organic described. present future developments green education chemical technology considered.
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