Solid basic catalysts

New aluminophosphate oxynitrides solid basic catalysts have been synthesised by activation under ammonia of an AIPO4 precursor. When the nitrogen content increases, XPS points out two types of nitrogen phosphorus bonding. The conversions in Knoevenagel condensation are related to the surface nitrogen content. Platinum supported on aluminophosphate oxynitride is an active catalyst for isobutane dehydrogenation. 

Fig. 3. Reactions catalyzed by solid basic catalysts. The number of the modified catalyst (see Table 3) and the best optical yield are given as (Nr/ee).

N. Villandier, I. Adam, F. Jerome, J. Barrault, R. Pierre, A. Bouchu, J. Fitremann, and Y. Queneau, Selective synthesis of amphiphilic hydroxyalkylethers of disaccharides over solid basic catalysts. Influence of the superficial hydrophilic-lipophilic balance of the catalyst, J. Mol. Catal. A Chem., 259 (2006) 67-77. 

Bancquart, S., Vanhove, C., Pouilloux, Y. and Barrault, J. Glycerol transesterification with methyl stearate over solid basic catalysts. I. Relationship between activity and basicity, Appl. Catal., A, 2001, 218, 1-11. 

Hydrotalcites (HT) belongs to the class of anionic clay minerals, also known as layered double hydroxides (LDHs). They are probably one of the best known and used solid basic catalyst [212[. Their properties in catalytic organic reactions have been discussed extensively by Jacobs et al. [256[. More recent aspects have been analyzed briefly also... 

Solid basic catalysts have been extensively studied during the last ten years and the scientific literature on the subject is becoming more and more abimdant. The main goal of these works is the replacement of the liquid basic catalysts used in industrial reactions such as alkylation, condensation, and isomerization [1]. At... 

Mg-Al mixed oxides obtained by thermal decomposition of anionic clays of hydrotalcite structure, present acidic or basic surface properties depending on their chemical composition [1]. These materials contain the metal components in close interaction thereby promoting bifunctional reactions that are catalyzed by Bronsted base-Lewis acid pairs. Among others, hydrotalcite-derived mixed oxides promote aldol condensations [2], alkylations [3] and alcohol eliminations reactions [1]. In particular, we have reported that Mg-Al mixed oxides efficiently catalyze the gas-phase self-condensation of acetone to a,P-unsaturated ketones such as mesityl oxides and isophorone [4]. Unfortunately, in coupling reactions like aldol condensations, basic catalysts are often deactivated either by the presence of byproducts such as water in the gas phase or by coke build up through secondary side reactions. Deactivation has traditionally limited the potential of solid basic catalysts to replace environmentally problematic and corrosive liquid bases. However, few works in the literature deal with the deactivation of solid bases under reaction conditions. Studies relating the concerted and sequential pathways required in the deactivation mechanism with the acid-base properties of the catalyst surface are specially lacking. 

The mechanism of the reactions in the presence of solid basic catalysts is based on the assumption that is dissociatively adsorbed on solid surfaces. In the same... 

Alumina can be impregnated with potassium fluoride, creating a solid, basic catalyst [145]. This solid has a wide range of catalytic applications involving elimination, condensation and addition reactions. Included in this group are the Michael additions of nitroalkanes to a, 3-unsaturated carbonyls (equation 4.35) [80]. 

General Mechanism for Base Catalysis. When a solid basic catalyst such a polar oxide is used, the reaction depicted in Scheme 1 occurs through... 

Meher, L. C., M. G. Kulkarni, A. K. Dalai, and S. N. Naik. 2006. Transesterification of Karanja (Pongamia Pinnata) Oil by Solid Basic Catalysts. European Journal of Lipid Science and Technology 108 (5) 389-397. 

Solid basic catalysts such as K-X zeolite and Cs-loaded K-X zeolite have been studied by CO2 adsorption microcalorimetry [138]. Carbon dioxide adsorbed on K-X with a Affads of about 70 kj mol up to a loading of about 80 xmolg The addition of cesium to K-X zeolite increased both the heat of adsorption (to more than 100 kJ mor ) and the maximum CO2 uptake. Nonetheless, the heats of carbon dioxide adsorption on Cs/K-X zeolites remained 50 kJ mol lower than on, for example, MgO or CS/AI2O3. The stronger basicity of Cs/K-X compared to K-X can be attributed to the occluded alkali metal oxide species, which may be either cesium or potassium oxide. The values of AHads on Cs/K-X samples were similar to those reported previously for Cs-loaded into Cs-X using analogous synthesis procedures [139]. 

Solid Basic Catalysts Oxides Containing Alkah,... 

Lingfeng, C., Guomin, X., Bo, X., and Guangyuan, T. Transesterification of cottonseed oil to biodiesel by using heterogeneous solid basic catalysts. Energy Fuels 21, 3740-3743 (2007). 

Manrfquez-Ramfrez, M., et al, 2013. Advances in the transesterification of triglycerides to biodiesel using MgO—NaOH, MgO—KOH and MgO—Ce02 as solid basic catalysts. Catalysis Today 212, 23—30. Available at http //www.sciencedirect.com/science/article/ pii/S0920586112007833 (accessed 27.04.15.). 

L.C. Meher, 2006, Transesteiification of karanja (Pongamia pinnata) oil by solid basic catalysts. Eur. J. Lipid Sci. Technol. 108, 389-397. 

---