نتایج جستجو برای: catalyst free
تعداد نتایج: 553796 فیلتر نتایج به سال:
a mild and green method has been developed for the preparation of coumarins derivatives through the one-pot reactions. in our study,various phenols and ethyl acetoacetate compound in which we used silica-supported boron sulfonic acid [sio2/b(so4h)3] as a new, highly efficient and tri-functional inorganic brønsted acid catalyst were processed under solvent-free condition and thermal. the catalys...
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...
Platinum group metal-free (PGM-free) catalyst with different loadings was investigated in air breathing electrodes microbial fuel cells (MFCs). Firstly, the electrocatalytic activity towards oxygen reduction reaction (ORR) of the catalyst was investigated by rotating ring disk electrode (RRDE) setup with different catalyst loadings. The results showed that higher loading led to an increased in ...
BINAM-prolinamides are very efficient catalyst for the synthesis of non-protected and N-benzyl isatin derivatives by using an aldol reaction between ketones and isatins under solvent-free conditions. The results in terms of diastereo- and enantioselectivities are good, up to 99% de and 97% ee, and higher to those previously reported in the literature under similar reaction conditions. A high va...
a highly efficient and simple method for the preparation of α,α´-bis(arylidene)cycloalkanones under solvent-free conditions has been developed. the crossed-aldol condensation of cycloalkanones (1 eq.) with arylaldehydes (2 eq.) in the presence of 2.5 mol% of ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate {[dsim]hso4} afforded the title compounds in high yields and short reaction ...
An experimental approach for the production of catalyst-free hyperpolarised ethanol solution in water via heterogeneous hydrogenation of vinyl acetate with parahydrogen and the subsequent hydrolysis of ethyl acetate was demonstrated. For an efficient hydrogenation, liquid vinyl acetate was transferred to the gas phase by parahydrogen bubbling and almost completely converted to ethyl acetate wit...
This article describe the applicability of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2].2Cl) as a green, versatile and Brönsted acidic ionic catalyst in the promotion of the synthesis of phthalazine derivatives via one-pot three component reaction between aromatic aldehydes, 1,3-diketone derivatives and phthalhydrazide under solvent-free reaction cond...
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