Patent ID: 8450518

Claim:
A method for preparing a carbamate, comprising (1) reacting (a) an aliphatic substituted urea and/or a derivative thereof having the general formula (I): R 1 R 2 N—CO—NR 3 R 4 (I) wherein: R 1 , R 2 , R 3 and R 4 are each independently selected from the group consisting of a hydrogen atom, an aliphatic group or a derivative thereof, a cycloaliphatic group or a derivative thereof, and an araliphatic group or a derivative thereof; with (b) a hydroxyl group containing compound having the general formula (II): R 5 (OH) n (II) wherein: R 5 is independently selected from the group consisiting of an aliphatic group or a derivative thereof, a cycloaliphatic group or a derivative thereof, an araliphatic group or a derivative thereof, and an aromatic group or a derivative thereof, and n represents 1, 2, 3 or 4; in the presence of (c) a catalyst comprising a catalytically active component and a catalyst support with said catalytically acid component being carried by said catalyst support, wherein said catalytically active component comprises a transition metal oxide and/or a composite of a transition metal oxide, wherein: (i) said transition metal oxide corresponds to the general formula: AO x , wherein: A is a transition metal element, and x represents a number within the range of 0.5 to 40; (ii) said cormposite of a transition metal oxide corresponds to one of the general formulas: AO x —BO y or AO x —BO y —CO z , wherein in each formula: A, B and C each independently represent a transition metal element, and x, y and z each independently represent a number within the range of 0.5-4; wherein said transition metal element is selected from the group consisting of vanadium, chromium, molybdenum, tungsten, manganese, iron, nickel palladium, patinum, copper, cadmium, mercury, titanium, lanthanum, cerium, neodynium, ytterbium, praseodymium, promethium, samarium, gadolinium, terbium, holmium, erbium, thulium and lutetium; and wherein said catalyst support: (i) comprises a material which is selected from the group consisting of silica gel, Al 2 O 3 , SnO 2 , TiO 2 , MgO, ZnO, ZrO 2 and SiO 2 , (ii) the average diameter of said catalyst support ranges from 0.01-10 mm, (iii) the pore volume of said catalyst support ranges from 0.01-2 ml/g, and (iv) the specific surface area of said catalyst support ranges from 1 to 2000 m 2 /g; thereby forming a carbamate having the general formula (III): (R 1 R 2 N—CO—O) n R 5 (III) wherein: R 1 and R 2 are each independently selected from the group consisting of a hydrogen atom, an aliphatic group or a derivative thereof, a cycloaliphatic group or a derivative thereof, and an araliphatic group or a derivative thereof, R 5 is independently selected from the group consisiting of aliphatic group or its derivatives, cycloaliphatic group or its derivatives, araliphatic group or its derivatives, and aromatic group or its derivatives, and n represents 1, 2, 3 or 4.