| abstract |
Disclosed are a glycosidation catalyst comprising at least one of heteropoly acids represented by the formula n n H.sub.a X.sub.p M.sub.q O.sub.r ·bH.sub.2 O n n wherein X is P, As, Si or Ge, M is at least one species selected from the group consisting of Mo, W and V, a is 3 4 or 6, b is an integer of 0 to 30, p is 1 or 2, q is 12 or 18, and r is 40 or 62, with the proviso that when X is P or As, a is 3 or 6; when X is Si or Ge, a is 4; and further (1) when X is P or As and a is 3, or when X is Si or Ge and a is 4, M is at least one species selected from the group consisting of Mo, W and V, p is 1, q is 12 and r is 40; and (2) when X is P or As and a is 6, M is Mo or W, p is 2, q is 18 and r is 62, and a process for preparing a glycoside derivative by using said catalyst. |