Glycerol catalytic conversion

An interesting comparison can be made with chemical techniques for glycerol treatment and dihydrogen production. Table 8.5 compares the performance of the above strain K4 with that of a catalytic conversion of aqueous glycerol [37]. 

Zhou C-H, Beltramini JN, Fan Y-X, Lu GQ (2008) Chemoselective catalytic conversion of glycerol as a biorenewable source to valuable ctunmodity chemicals. Chem Soc Rev 37 527-549... 

Another interesting field involving membrane reactors is the partial oxidation of methane to methanol, which is a process for the catalytic conversion of methane from natural gas and air oxygen to methanol by the partial oxidation as well as the steam reforming of methane, ethanol or glycerol for hydrogen production (Basile et a/., 2011 lulianelli et al, 2010,2011). 

A first-order kinetics with respect to glycerol was adopted to describe the catalytic conversion of glycerol to hydrogen by aqueous-phase reforming on Pt/y-alumina catalyst [148]. Extra information about two-bed membrane reactor model is given in Iliuta et al. [148]. 

The catalytic conversion of ethanol and glycerol produces short aldehydes or ketones, which can be converted to more suitable molecular weight products. Aldol condensation reactions of these molecules lead also to the formation of G-C bonds. These reactions are generally catalyzed by bases. These types of condensation over solid bases lead mainly to aldol, ketol, or a,p-unsaturated carbonyl compounds. 

Another example of a DMC-catalyzed esterification reaction is the esterification of free fatty acids with glycerol [32]. This reaction again used Zn-Fe(II)-DMC as a catalyst yet the activity of the material could be tuned by varying the synthesis temperature. As such, DMCs with different acidities (as evidenced by NHj-TPD), crystallite sizes (calculated from the Debye-Scherrer equation), particle sizes (studied with scanning electron microscopy (SEM)), and BET (Brunauer, Emmett and Teller) specific surface areas were obtained. The highest catalytic conversions were observed for the catalysts synthesized at elevated temperatures these materials featured both the highest specific surface area and the largest number of acid sites. 

Conna A, Huber GW, Sauvanaud L, O Connor P. Biomass to chemicals catalytic conversion of glycerol/ water mixtures into acrolein, reaction network. J Catal 2008 257 163-71. 

High-yield catalytic conversion of glycerol into 1,2-propanediol without using an external H2 supply is possible on Pt impregnated NaY zeolites, characterized by extra-zeolitic metal clusters combined with traces of Bronsted acidity. A comparison is made with NaY zeolite supported Pt catalysts prepared by a conventional ion-exchange procedure. Both materials were characterized using SEM, XRD and CO chemisorption. 

Here, the reaction proceeds quickly enough simply by heating the mixture of urea and glycerol, although the addition of a catalytic system will improve the conversion yield of glycerol. The role of the metal center is to facilitate the interaction between the urea carbonyl and the glycerol alcoholic group, with the consequent release of ammonia. 

---