Hydroxyapatite as a new solid support for the Knoevenagel reaction in heterogeneous media without solvent

Sebti, Saı̈d M.; Tahir, Rachid; Nazih, Rachid; Saber, Ahmed F.; Boulaajaj, Saïd

doi:10.1016/s0926-860x(01)00961-9

Cited by 115 publications

(60 citation statements)

References 36 publications

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“…Opre et al [22,23] also studied the selective oxidation of alcohols with oxygen on cobalt promoted ruthenium-hydroxyapatite. Earlier, hydroxyapatites were used as supports in a many studies [24][25][26][27][28]. Recently, our group has also successfully used cobalt, iridium and platinum hydroxyapatites as catalysts for solvent-free Knoevenagel condensation reactions of aldehydes with esters, resulting in good yields [29,30].…”

Section: +mentioning

confidence: 99%

Synthesis of thermally stable metal substituted hydroxy apatites for the selective oxidation of light paraffins

Singh¹,

Jonnalagadda²

2012

Bull. Chem. Soc. Eth.

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ABSTRACT. Hydroxyapatite and a series of hydroxyapatite-type compounds containing Co, Fe or Sr were synthesized by co-precipitation and characterized by ICP-OES, BET, IR, Raman spectroscopy, powder and in-situ XRD, SEM, TEM, TPR, TPD and TGA. In-situ XRD and TGA studies indicate that the materials are able to maintain their structure at temperatures reaching 900 °C. The TPD data indicated that acidic sites of varying strengths were present in all the three hydroxyapatites. From SEM, the surface of the materials consisted of an agglomeration of irregular plate-like particles. The catalytic activity of the compounds was investigated in the oxidation of n-pentane and n-hexane. The conversion of the feed and composition of the products were largely influenced by changes in the temperature and flow rates. For n-pentane, the products consisted of lower hydrocarbons and oxygenated compounds, carbon oxides and very small amounts 1,3-pentadiene, furan and furfural. Low conversions of n-hexane were obtained for all the tested catalysts and selective products were the hexene isomers and some aromatics.

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Section: +mentioning

confidence: 99%

Synthesis of thermally stable metal substituted hydroxy apatites for the selective oxidation of light paraffins

Singh¹,

Jonnalagadda²

2012

Bull. Chem. Soc. Eth.

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“…Hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 (denoted as HA), is a form of bioceramics material [1]. It is chemically similar to bones and hard tissues found in humans.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, HA has also been used as an acidic catalyst for Friedel-Crafts alkylation and Knoevenagel reactions [6].…”

Section: Introductionmentioning

confidence: 99%

Template-Based Synthesis of Nanoporous Hydroxyapatite

2012

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Hydroxyapatite (HAp) particles, a potential starting material for bone substitutes, with nanopores were synthesized in the presence of cetyltrimethylammonium bromide (CTAB) and P123 as cationic and nonionic surfactants as the structuring units. Effect of nonionic surfactant concentration on surface areas is also investigated. Based on N 2 adsorption-desorption isotherms investigation, surface area increased up to 50 m 2 /g by using P123 and 147 m 2 /g by using CTAB as porosity agent. Pore structure remained even after the removal of surfactant and calcinations at 400 • C.

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“…Ethyl cyanoacetate showed a slightly slower reaction due to the lower activity it has (entry 2). Other aldehydes behaved in a similar manner and produced high yields of their respective products (entries [3][4][5][6][7][8][9][10][11][12][13][14]. In all reactions with 2b, only geometric E isomers were obtained in high yields within 1-2 min.…”

Section: Resultsmentioning

confidence: 95%

“…9−11 Many alternative methods to the original Knoevenagel process have been developed in recent years so that the reaction proceeds under smoother conditions. In this regard, the use of ionic liquids, 12 nanocatalysts, 13 heterogeneous conditions, 14 and microwave irradiation 15 can be highlighted. Nevertheless, several of these methods still involve the use of expensive reagents, require relatively harsh conditions, or need extra additives to proceed.…”

Section: Introductionmentioning

confidence: 99%

Aqueous DABCO, an efficient medium for rapid organocatalyzed Knoevenagel condensation and the Gewald reaction

Abaee¹,

Cheraghi²

2014

Turk J Chem

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Abstract:In the presence of water and 1,4-diazabicyclo[2.2.2]octane, several aldehydes and cyclic ketones underwent efficient Knoevenagel condensation with malononitrile and ethyl cyanoacetate to produce the respective α . β -unsaturated systems within fairly short time periods. As a result, high yields of conjugated products were easily obtained. Products could be engaged in a Gewald reaction, either stepwise or in situ, to produce efficiently their respective 2-aminothiophenes within 4-7 h.

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Hydroxyapatite as a new solid support for the Knoevenagel reaction in heterogeneous media without solvent

Cited by 115 publications

References 36 publications

Synthesis of thermally stable metal substituted hydroxy apatites for the selective oxidation of light paraffins

Synthesis of thermally stable metal substituted hydroxy apatites for the selective oxidation of light paraffins

Template-Based Synthesis of Nanoporous Hydroxyapatite

Aqueous DABCO, an efficient medium for rapid organocatalyzed Knoevenagel condensation and the Gewald reaction

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