Process for skeletal isomerization of n-alkenes

A method for skeletal isomerization of n-alkenes into isoalkenes and enrichment of isoalkenes in alkene-containing hydrocarbon mixtures which comprises isomerizing n-alkenes at temperatures of 593 to 823K and pressures of 98 to 2100 kPa in the presence of an isomerization catalyst, the isomerization catalyst comprising a microporous alumophosphate with a molecular sieve structure and with pore inlet openings of 0.4 to 0.6 nm diameter admixed with a binder, shaped, and then activated at temperatures of 623 to 873K;

• said alumophosphate containing silicon and at least one metal in a lattice structure having an X-ray diffractogram (Cu-K-alpha radiation) characterized by interferences in at least the following lattice plane ranges:
• d(A) :
• 2.8 to 3.0;
• 3.8 to 4.1;
• 4.0 to 4.5;
• 10 to 12;
• and the silicon contained in the alumophosphate comprising silicon of activated silicon dioxide which exhibits an IR spectrum according to FIG. 1 thereby producing isoalkenes.