Chlorinated 4-methylphthalic anhydrides

Details Chlorinated 4-methylphthalic anhydrides Chlorinated 4-methylphthalic anhydrides

1978-04-24

1981-11-24

Evans, Joseph E.

Chemistry of carbon compounds

Miscellaneous organic carbon compounds

C-metal

562480, 260365, 260326C, C07C 6316, C07D30789

Patent

active

043023967

ABSTRACT:
Novel chlorinated 4-methylphthalic acids or anhydrides of the general formula ##STR1## wherein n is an integer of 1, 2 or 3, with the proviso that when n is 1, the chlorine atom is positioned at 3- or 5-position and when n is 2, the chlorine atoms are positioned at 3- and 5-positions. The new compounds are produced by dissolving 4-methylphthalic anhydride in concentrated sulfuric acid or fuming sulfuric acid to form a solution, and reacting the solution with chlorine at room temperature preferably in the presence of a catalytic amount of iodine, thereby to yield a crude product containing a mixture of chlorinated 4-methylphthalic acids. By subjecting the mixture to a thermal dehydration treatment in an inactive organic solvent, each of the chlorinated compounds may be isolated as its corresponding anhydride in the form of crystals.
These chlorinated 4-methylphthalic anhydrides are valuable as intermediates for the preparation of dyestuffs or pigments.

REFERENCES:
patent: 3098095 (1963-07-01), Knobloch et al.
patent: 3232737 (1966-02-01), Willard et al.
patent: 3940419 (1976-02-01), Diehl et al.
Venkataraman, The Chemistry of Synthetic Dyes, vol. 1, pp. 140, 142, 160-163 (1952), Academic Press, Inc., New York. _
Chemical Abstracts vol. 44, column 2,561(g) (1950).
Chemical Abstracts vol. 45, column 2,442(e) (1951).
Chemical Abstracts. vol. 73, column 136,771(s) (1970).
Chemical Abstracts vol. 28, column 1,339.sup.4 (1934).
Chemical Abstracts vol. 26, column 135.sup.8 (1932).
Chemical Abstracts vol. 68, column 104,957(n) (1968).
Chemical Abstracts vol. 47, column 543(i), 544(a).

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