Mixed oxide composite comprising calcium oxide and tricalcium aluminate
AssigneeUniversity Court of the University of St Andrews
InventorsJohn Thomas Sirr Irvine, Alfredo Bonaccorso, Despoina Papargyriou
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Abstract
The invention relates to a composite oxide comprising CaO stabilised by Ca3AI2O6 (C3A), wherein the composite is in the form of particles. The mixed oxide composite is useful as a catalyst in the transesterification of triglycerides, e.g. in the production of biodiesel. Calcium leaching is more hindered in CaO—Ca3AI2O6 (2Ca/AI) than in CaO-AI2O3.
Claims31
A mixed oxide composite comprising CaO and Ca3Al2O6, wherein the composite is in the form of particles, wherein the particles are supported on a porous support.
A method for preparing a mixed oxide composite, said method comprising:
- (a) heating an aqueous solution comprising (i) aluminium nitrate or aluminium nitrate hydrate, (ii) calcium nitrate or calcium nitrate hydrate, and (iii) an organic fuel until the solution combusts to form a powder;
- and
- (b) calcining the powder at a temperature of from 1000° C. or higher.
A method of activating a mixed oxide composite comprising CaO and Ca3Al2O6, comprising heating a C1 to C4 alcohol with glycerol in the presence of the mixed oxide composite so as to form calcium diglyceroxide.
A method for the transesterification of monoglycerides, diglycerides or triglycerides comprising the steps of:
- heating a mixture of C1-C4 alcohol, glycerol and a mixed oxide catalyst comprising CaO and Ca3Al2O6, so as to form at least calcium diglyceroxide;
- contacting the calcium diglyceroxide with monoglycerides, diglycerides or triglycerides;
- and
- transesterifying the monoglycerides, diglycerides or triglycerides.
A mixed oxide composite comprising CaO and Ca3Al2O6, wherein the amount of CaO and Ca3Al2O6 in the composite is 100 wt % of the total weight of the composite.
A mixed oxide composite comprising CaO and Ca3Al2O6, wherein the composite is a uniformly dispersed mixture of CaO and Ca3Al2O6.
Dependencies are inferred from the claim text.