Process for producing isoprene

A process for producing isoprene comprising reacting formaldehydewith trimethylcarbinol in a liquid phase upon heating to a temperature of about 200.degree. C in the presence of a catalyst selected from the group consisting of sulphamic acid, an aromatic ammonium compound containing a sulpho group in ortho-, meta or para-position and having the formula:

• ##STR7## where R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, and aralkyl;
• hydrogen atoms in the benzene ring may be substituted by radicals of the group consisting of a methyl, halide, and a sulpho group;
• and a catalyst selected from the group consisting of ammonium condensed compound of the naphthalene series containing a sulpho group and having the formula:
• ##STR8## wherein R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, and aralkyl;
• and a reaction product of said ammonium compounds with formaldehyde, followed by isolation of the desired product.

A process for producing isoprene comprising reacting formaldehyde with isobutylene in a liquid phase upon heating to a tempterature of about 200.degree. C in the presence of a catalyst selected from the group consisting of sulphamic acid, an aromatic ammonium compound containing a sulpho group in ortho-, meta- or para-position and having the formula:

• ##STR9## wherein R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, and aralkyl;
• hydrogen atoms in the benzene ring may be substituted by radicals of the group consisting of a methyl, halide, and sulpho group;
• a catalyst selected from the group consisting of ammonium condensed compound of the naphthalene series containing sulpho group and having the formula:
• ##STR10## wherein R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, alkyl, aryl, alkylaryl, and aralkyl;
• and a reaction product of said ammonium compounds with formaldehyde, followed by isolation of the desired product.

A process for producing isoprene comprising reacting formaldehyde with a compound selected from the group consisting of isobutylene, trimethylcarbinol and mixtures thereof in a liquid phase upon heating to a temperature of about 200.degree. C in the presence of a catalyst selected from the group consisting of sulphamic acid, an aromatic ammonium compound containing a sulpho group in ortho-, meta- or para-position and having the formula:

• ##STR11## wherein R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, an alkyl, aryl, alkylaryl, aralkyl;
• hydrogen atoms in the benzene ring may be substituted by radicals of the group consisting of methyl alkyl, halide, and sulpho group;
• as well as a catalyst selected from the group of ammonium condensed compounds of the naphthalene series containing a sulpho group and having the formula:
• ##STR12## wherein R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, an alkyl, aryl, alkylaryl, aralkyl, and a reaction product of said ammonium compounds with formaldehyde, followed by isolation of the desired product.