Journal ArticleDOI
Mesoporous metal(IV) phosphates as high performance acid catalysts for the synthesis of photochromic bis-naphthopyran via Claisen rearrangement
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In this paper, a facile and efficient one-step method for the synthesis of highly active mesoporous zirconium and tin(IV) phosphate that exhibit excellent catalytic activity for photochromic bis-naphthopyran via the Claisen rearrangement has been established.Abstract:
In this work, a facile and efficient one-step method for the synthesis of highly active mesoporous zirconium and tin(IV) phosphate that exhibit excellent catalytic activity for the synthesis of photochromic bis-naphthopyran via the Claisen rearrangement has been established. The synthesized catalysts were characterized by different textural and spectroscopic techniques such as XRD, FTIR spectra, SEM, TEM and N2 adsorption–desorption at −196 °C. The surface acidity of the prepared catalysts were determined by nonaqueous potentiometric titration with n-butylamine and FTIR of chemisorbed pyridine. XRD and N2 adsorption–desorption measurements showed that, the samples have some mesoporous structure. The surface acidity measurement showed that the samples contain mixture of Lewis and Bronsted acid sites. The results showed that zirconium phosphate samples have higher surface acidities than tin phosphate samples, and the samples with Zr:P ratio 1:3 and Sn:P ratio 1:2 showed the highest surface and Bronsted acidities. The prepared catalysts showed excellent catalytic activity for the synthesis of photochromic bis-naphthopyran via the Claisen rearrangement. High yield (~99 %) with 100 % selectivity of photochromic bis-naphthopyran was obtained in shorter reaction time at room temperature. These acid catalysts may solve the problematic low yield and purification difficulties of the photochromic chromenes reported previously.read more
Citations
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Simple and green route for preparation of tin phosphate catalysts by solid-state grinding for dehydration of glucose to 5-hydroxymethylfurfural (HMF)
Kasanneni Tirumala Venkateswara Rao,Sadra Souzanchi,Zhongshun Yuan,Madhumita B. Ray,Chunbao (Charles) Xu +4 more
TL;DR: In this article, a simple and green method for the synthesis of tin phosphate (SnP) catalysts for glucose to HMF transformation was demonstrated, where the catalytic activity of the obtained SnP catalysts depended on the P/Sn ratio.
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Competent, selective and high yield of 7-hydroxy-4-methyl coumarin over sulfonated mesoporous silica as solid acid catalysts
Abd El Rahman S. Khder,Abd El Rahman S. Khder,Saleh A. Ahmed,Saleh A. Ahmed,Khalid S. Khairou,Hatem M. Altass +5 more
TL;DR: In this article, high-ordered mesoporous MCM-41 and SBA-15 have been synthesized and functionalized with different amounts of propyl sulfonic acid groups using 3-mercaptopropyltrimethoxysilane as sulfur source.
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Abd El Rahman S. Khder,Abd El Rahman S. Khder,Sheikha S. Ashour,Hatem M. Altass,Khalid S. Khairou +4 more
TL;DR: In this paper, Pd nanoparticles were precipitated over iron oxide that prepared through two basic approaches to look for better dispersion of nanoparticles and robust catalyst for carbon monoxide oxidation.
Journal ArticleDOI
Highly efficient, recyclable cerium-phosphate solid acid catalysts for the synthesis of tetrahydrocarbazole derivatives by Borsche–Drechsel cyclization
Hatem M. Altass,Abdelrahman S. Khder,Abdelrahman S. Khder,Saleh A. Ahmed,Saleh A. Ahmed,Moataz Morad,Abdullah A. Alsabei,Rabab S. Jassas,Khalid Althagafy,Awad I. Ahmed,Reda S. Salama +10 more
TL;DR: In this paper, a series of cerium phosphate catalysts with different cerium to phosphate molar ratios have been synthesized by means of FTIR, DTA, TGA, XRD, N2 adsorption-desorption and SEM.
References
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Nb2O5·nH2O as a heterogeneous catalyst with water-tolerant Lewis acid sites.
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