Ba(OH)2 as the catalyst in organic reactions. Part XIV. Mechanism of Claisen–Schmidt condensation in solid–liquid conditions

1987 ◽  
Vol 65 (6) ◽  
pp. 1165-1171 ◽  
Author(s):  
A. Aguilera ◽  
A. R. Alcantara ◽  
J. M. Marinas ◽  
J. V. Sinisterra
Keyword(s):  
Infrared Spectroscopy ◽  
Textural Properties ◽  
Organic Reactions ◽  
Barium Hydroxide ◽  
Liquid Reaction ◽  
Solid Liquid

The mechanism of the Claisen–Schmidt condensation, catalyzed by a series of activated barium hydroxide catalysts, is discussed. Two kinds of ketones are studied: R—CO—CH3 (R = Me, Et, Pri, But) and acetophenone (R = Ph). The influence of the chemical and textural properties of the catalysts, as well as the nature of the solvent, are studied. The process is an interfacial solid–liquid reaction between the adsorbed carbanion and the benzaldehyde. The different structures of the adsorbed carbanion produced from Ph—CO—CH3 and R—CO—CH3 are analyzed by infrared spectroscopy, and could explain the different reactivities observed in the process. The kinetic runs are discussed.

Barium Hydroxide as Catalyst in Organic Reactions; V. Application in the Horner Reaction under Solid-Liquid Phase-Transfer Conditions

Synthesis ◽  
1985 ◽  
Vol 1985 (12) ◽  
pp. 1097-1100 ◽  
Author(s):  
J. V. Sinisterra ◽  
Z. Mouloungui ◽  
M. Delmas ◽  
A. Gaset
Keyword(s):  
Liquid Phase ◽  
Phase Transfer ◽  
Organic Reactions ◽  
Barium Hydroxide ◽  
Solid Liquid

Characterization and catalytic properties of a saponite clay modified by acid activation

Clay Minerals ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 633-643 ◽  
Author(s):  
F. Kooli ◽  
W. Jones
Keyword(s):  
Infrared Spectroscopy ◽  
Room Temperature ◽  
Textural Properties ◽  
Acid Sites ◽  
Single Type ◽  
Activation Process ◽  
Acid Activation ◽  
Strongly Correlated ◽  
Lewis Site ◽  
Adsorbed Pyridine

AbstractA natural saponite was acid activated at room temperature or 90°C with different acid/clay ratios and the products were characterized by powder X-ray diffraction, infrared spectroscopy and thermogravimetry. The leaching of Mg from the octahedral sheets is enhanced by an increase in the acid/clay ratio and by an increase in temperature of activation. Textural properties are reported, and it appears that they are strongly correlated to the presence of a noncrystalline silica phase which is formed during the acid activation process. The desorption of cyclohexylamine indicates that for samples activated at 90°C the number of acid sites in the acidactivated saponites decreases following severe acid treatment. Infrared spectroscopy of adsorbed pyridine on samples after calcination at 500°C suggests that acid activation at 90°C produces a single type of Bronsted site but two types of Lewis sites whereas activation at room temperature results in only one type of Lewis site in addition to a Brønsted site. The two Lewis sites are suggested to originate from residual Al in the clay structure and to AI exsolved from the layers during activation. The dehydration of pentan-1-ol has been used as a further probe to measure acidity by monitoring the degree of conversion and selectivity for the different samples.

scholarly journals Improved Understanding of the Sulfidization Mechanism in Amine Flotation of Smithsonite: An XPS, AFM and UV–Vis DRS Study

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 370 ◽  
Author(s):  
Ruizeng Liu ◽  
Bin Pei ◽  
Zhicheng Liu ◽  
Yunwei Wang ◽  
Jialei Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
High Reactivity ◽  
Phase Imaging ◽  
Solid Product ◽  
Force Microscopy ◽  
Atomic Force ◽  
Liquid Reaction ◽  
Solid Liquid ◽  
Heterogeneous Solid

Sulfidization is required in the amine flotation of smithsonite; however, the sulfidization mechanism of smithsonite is still not fully understood. In this work, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS) were used to characterize sulfidized and unsulfidized smithsonite. The XPS and UV–vis DRS analyses showed that smithsonite sulfidization is a transformation of ZnCO3 to ZnS on the smithsonite surfaces. However, this transformation is localized, resulting in the coexistence of ZnCO3 and ZnS or in the formation of ZnS island structures on the sulfidized smithsonite surfaces. AFM height imaging showed that sulfidization can substantially change the surface morphology of smithsonite; in addition, AFM phase imaging demonstrated that sulfidization occurs locally on the smithsonite surfaces. Based on our findings, it can be concluded that smithsonite sulfidization is clearly a heterogeneous solid–liquid reaction in which the solid product attaches at the surfaces of unreacted smithsonite. Smithsonite sulfidization involves heterogeneous nucleation and growth of ZnS nuclei. Moreover, the ZnS might nucleate and grow preferentially in the regions with high reactivity, which might account for the formation of ZnS island structures. In addition, sphalerite-structured ZnS is more likely to be the sulfidization product of smithsonite under flotation-relevantconditions, as also demonstrated by the results of our UV–vis DRS analyses. The results of this study can provide deeper insights into the sulfidization mechanism of smithsonite.

Solid-Liquid Reaction Synthesis and Characterization of Bioinorganic Complexes of Nicotinic Acid with Antimony(III) and Bismuth(III) Ion

2011 ◽  
Vol 282-283 ◽  
pp. 267-270 ◽  
Author(s):  
Guo Qing Zhong ◽  
Mei Gu ◽  
Yan Zhang
Keyword(s):  
Crystal Structure ◽  
Nicotinic Acid ◽  
Room Temperature ◽  
Synthesis And Characterization ◽  
Reaction Synthesis ◽  
Monoclinic System ◽  
Triclinic System ◽  
Liquid Reaction ◽  
Solid Liquid

Bioinorganic complexes of nicotinic acid with trivalent antimony and bismuth are synthesized by solid-liquid reaction at room temperature. The formula of the complexes is Sb(C5H4NCOOH)2Cl3•H2O and Bi(C5H4NCOOH)2Cl3•H2O respectively. The crystal structure of the complex of nicotinic acid and Sb(III) belongs to triclinic system and that of nicotinic acid and Bi(III) belongs to monoclinic system. Thermal analysis can indicate the complex formation between antimony or bismuth ion and nicotinic acid.

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