A facile synthesis of amides by selective hydration of nitriles using modified natural phosphate and hydroxyapatite as new catalysts

Natural phosphate as an efficient and green catalyst for synthesis of tetraketone and xanthene derivatives

“…SEM images of NP show that there are porosity and a heterogeneous microstructure. The results are in good agreement with the earlier studies [3,9]. The average particle diameters were measured at around 10-14 and 20-22 lm.…”

“…The phosphate particles were refluxed and washed with water, calcined at 900°C for 2.5 h, then was washed again and recalcined at 900°C for 0.5 h prior to use as catalyst [3,29]. The chemical composition was determined as: pH measurement of the catalyst A suspension of NP in deionized water was stirred at room temperature for 2 h and kept in closed vessel for 24 h without stirring.…”

“…Natural phosphate (NP) is readily available, cheap, nontoxic and a non-pollutant [2]. NP and synthetic phosphates such as fluorapatite (FAP, Ca 10 (PO 4 ) 6 F 2 ) or hydroxyapatite (HAP, Ca 10 (PO 4 ) 6 (OH) 2 ) [3] were used as efficient catalysts for various organic transformations, e.g. Knoevenagel condensation [4], transesterification reaction [5], Michael addition of mercaptans to a,b-unsaturated carbonyl compounds [6], synthesis of 5-arylhydantoins [7], a-hydroxyphosphonates [8], and Suzuki coupling reactions [9].…”

Nanoparticle‐Supported and Magnetically Recoverable Ruthenium Hydroxide Catalyst: Efficient Hydration of Nitriles to Amides in Aqueous Medium

“…[5] These methods suffer various drawbacks, especially the difficulty in separation of product and catalyst from the reaction mixture, as well as the use of inert atmosphere for handling air-sensitive metal catalysts. Heterogeneous systems have also been reported, such as alumina, [6] potassium fluoride doped Al 2 O 3 [7] and phosphates, [8] silica supported manganese oxides, [9] modified hydroxyapatite, [10] and ruthenium hydroxide coated on alumina and ferrites.…”

Effect of layers composition on leachate property from functional layer embedded landfill

“…TP in LR1 decreased from 1.45 to 0.56 mg/L in the first 9 weeks, and then increased to 2.36 mg/L in the end of 26 weeks. The materials in Layer 2, such as the cement, the lime, were effective in P removal in leachate through the physical adsorption and chemical sedimentation, and the ortho-phosphate in leachate could be also removed greatly by the Layer 2 in LR1 as the formation of Ca 3 (PO 4 ) 3 , hydroxyapatite (Bazi et al, 2006). Waste iron sand contributed to the removal of PO 4 3À as the precipitation, and lime and Ca 2+ will be helpful for the precipitation of P in leachate under a high pH of 10 as the following formula (Zhang et al, 2002).…”