A method of forming dialkyl carbonate is provided, which includes introducing carbon dioxide into a catalyst to form dialkyl carbonate, wherein the catalyst is formed by activating a catalyst precursor using alcohol, wherein alcohol is R.sup.3—OH, and R.sup.3 is C.sub.1-12 alkyl group or C.sub.5-12 aryl or heteroaryl group. The catalyst precursor is formed by reacting Sn(R.sub.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4, and Sn(R.sup.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4 have a molar ratio of 1:2 to 2:1. R.sup.1 is C.sub.1-10 alkyl group, R.sup.2 is H or C.sub.1-12 alkyl group, and L is O—(C═O)—R.sup.5, and R.sup.5 is C.sub.1-12 alkyl group. The dialkyl carbonate is ##STR00001##

A method of forming dialkyl carbonate is provided, which includes introducing carbon dioxide into a catalyst to form dialkyl carbonate, wherein the catalyst is formed by activating a catalyst precursor using alcohol, wherein alcohol is R.sup.3—OH, and R.sup.3 is C.sub.1-12 alkyl group or C.sub.5-12 aryl or heteroaryl group. The catalyst precursor is formed by reacting Sn(R.sub.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4, and Sn(R.sup.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4 have a molar ratio of 1:2 to 2:1. R.sup.1 is C.sub.1-10 alkyl group, R.sup.2 is H or C.sub.1-12 alkyl group, and L is O—(C═O)—R.sup.5, and R.sup.5 is C.sub.1-12 alkyl group. The dialkyl carbonate is

##STR00001##

The invention relates to a catalyst comprising a support, at least one noble metal M, tin, phosphorus and ytterbium, the content of phosphorus element being greater than or equal to 0.2% by weight and less than 0.4% by weight, and the content of ytterbium being less than or equal to 1% by weight relative to the mass of the catalyst. The invention also relates to the process for preparing the catalyst and to the use thereof in reforming.

The invention relates to a catalyst comprising a support, at least one noble metal M, tin, phosphorus and ytterbium, the content of phosphorus element being greater than or equal to 0.2% by weight and less than 0.4% by weight, and the content of ytterbium being less than or equal to 1% by weight relative to the mass of the catalyst. The invention also relates to the process for preparing the catalyst and to the use thereof in reforming.

A method of forming dialkyl carbonate is provided, which includes introducing carbon dioxide into a catalyst to form dialkyl carbonate, wherein the catalyst is formed by activating a catalyst precursor using alcohol, wherein alcohol is R.sup.3—OH, and R.sup.3 is C.sub.1-12 alkyl group or C.sub.5-12 aryl or heteroaryl group. The catalyst precursor is formed by reacting Sn(R.sub.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4, and Sn(R.sup.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4 have a molar ratio of 1:2 to 2:1. R.sup.1 is C.sub.1-10 alkyl group, R.sup.2 is H or C.sub.1-12 alkyl group, and L is O—(C═O)—R.sup.5, and R.sup.5 is C.sub.1-12 alkyl group. The dialkyl carbonate is ##STR00001##

This invention relates to a catalyst system comprising (a) at least one layer of a first catalyst comprising a dehydrogenation active metal on a solid support; (b) at least one layer of a second catalyst comprising a metal oxide; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst; and a process comprising contacting a hydrocarbon feed with the catalyst system.

This invention relates to a catalyst system comprising (a) at least one layer of a first catalyst comprising a dehydrogenation active metal on a solid support; (b) at least one layer of a second catalyst comprising a metal oxide; and (c) at least one layer of a third catalyst comprising a transition metal on an inorganic support; wherein the at least one layer of a second catalyst is sandwiched between the at least one layer of a first catalyst and the at least one layer of a third catalyst; and a process comprising contacting a hydrocarbon feed with the catalyst system.

The invention relates to a catalyst comprising a support, at least one noble metal M, tin, phosphorus and yttrium, the content of phosphorus element being less than or equal to 1% by weight, and the content of yttrium being less than or equal to 1% by weight relative to the mass of the catalyst. The invention also relates to the process for preparing the catalyst and to the use thereof in reforming.

The invention relates to a catalyst comprising a support, at least one noble metal M, tin, phosphorus and yttrium, the content of phosphorus element being less than or equal to 1% by weight, and the content of yttrium being less than or equal to 1% by weight relative to the mass of the catalyst. The invention also relates to the process for preparing the catalyst and to the use thereof in reforming.

Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.