Patent ID: 8309486

Claim:
A composite solid acid catalyst consisting of from 50% to 80% by weight of a porous inorganic support, from 15% to 48% by weight of a heteropoly compound loaded thereon, and from 2% to 6% by weight of an inorganic acid, said heteropoly compound having a general formula of M x H 8-n-x [AB 12 O 40 ], wherein A is a heteroatom P or Si, B is polyatom W or Mo, M is selected from the group consisting of alkali metals of Li, Na, K, Rb and Cs, alkali earth metals of Be, Mg, Ca, Sr and Ba, and NH 4 , n is the valence state of A, which is 4 or 5, x is any number from 0 to 4, and said inorganic acid is selected from HF or HCl, and said porous inorganic support is one or more selected from silicon oxide, alumina, active carbon, magnesium oxide, titanium oxide, natural or artificially synthetic aluminosilicate zeolite, molecular sieve, carbon fiber and natural clay, or mixtures thereof; wherein the composite solid acid catalyst has the acid sites type of Brönsted acid and has an acid sites density of not less than 1.4×10 −3 mol H + /g.