نتایج جستجو برای: heterogenous solid acid
تعداد نتایج: 926676 فیلتر نتایج به سال:
Phosphosulfonic acid as a multi solid site was easilyprepared from the reaction of ammonium dihydrogen phosphatewith chlorosulfonic acid in CCl4and for improved its catalyticactivity was supported nano Silica was extracted from husk ricecontains about 95% of Silica the size of extracted nano silica wasdetermined by SEM efficiency of this solid acid in four componentcondensation reaction of arom...
in this work, so3h-functionalizedphthalimide (sfp) as a so3h-containing solid acid is prepared by the reaction of phthalimide with chlorosulfonic acid, and characterized by ft-ir, 1h and 13c nmr, mass, tg, dtg, xrd and sem. then, it is utilized as a highly efficient, heterogeneous and green catalyst for the one-pot multi-component condensation of dimedone with arylaldehydes, β-ketoesters and am...
Phosphosulfonic acid as a multi solid site was easily prepared from the reaction of ammonium dihydrogen phosphate with chlorosulfonic acid in CCl4and for improved its catalytic activity was supported nano Silica was extracted from husk rice contains about 95% of Silica the size of extracted nano silica was determined by SEM efficiency of this solid acid in four comp...
Two highly efficient protocols for the production of bis-coumarins under solvent-free conditions have been introduced. The reaction of 4-hydroxycoumarin (2 eq.) with arylaldehydes (1 eq.) using phthalimide-N-sulfonic acid (PhtSA) or isatin-N-sulfonic acid (IsSA), as solid-acid catalysts, afforded the mentioned compounds with good to excellent yields in short times.Briefly, we have introduced tw...
The development of heterogenous catalysts using renewable materials has received wide attention. A catalyst been a preferred choice as it evades the disadvantages homogeneous catalysts, nevertheless, limited activity and longer separation process. current study emphasises preparation new magnetic oil palm empty fruit bunch (EFB) fibre carbon-based support material. effect different alkaline pre...
Further noncontrast CT scan was performed, which revealed well-defined, well-circumscribed smooth marginated solid cystic lesion in superficial and deep lobes of left parotid gland, predominantly in posteroinferior part of gland, medially the lesion extends into stylomandibular tunnel (Figure 1). On postcontrast CT, irregular nodular enhancement of solid part was noted and in close relation to ...
gastrointestinal stromal tumors (gists) are rare and these tumors are mesenchymal tumors that develop in the wall of the gi tract. the aim of this study was to report a case with gist in pregnancy in western iran. a 39-year-old pregnant female (g5 p4) was admitted with a chief complaint of abdominal pain and epigastric fullness on 12 th april 2016. sonography showed gestational age of 15w+1d an...
[b(oh)3]0.78[b(oh)2(oso3h)]0.22 or (bsa) was simply prepared by addition of chlorosulfonic acid to commercial boric acid at room temperature. this cheap and green solid acid was used as an efficient catalyst for synthesis of acylals from aldehydes under solvent-free conditions at room temperature.
To reduce the noise and vibration perturbations, it is beneficial to use the dissipative properties of poroelastic materials. These materials are generally not used alone, but rather inserted in composite mechanical assemblies made of elastic structures, poroelastic materials and air insertions. If these structures are assemblies of layers of materials, they are called multilayer complexes. If ...
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