Appeal No. 96-2803
Application No. 08/255,542
The subject matter on appeal is directed to a process for
reducing the mutagenicity of materials derived from coal tar
which include polynuclear aromatic compounds having three to
seven fused rings (such as benzopyrene) by alkylating the coal
tar in the presence of an acid catalyst with an alkylating
agent to introduce a branched chain alkyl group of three to
five carbon atoms into the polynuclear aromatic compounds.
Representative claim 21 is reproduced below:
21. A process for reducing the mutagenicity of a coal
tar containing polynuclear aromatic compounds having three to
seven fused aromatic rings, comprising the step of contacting
the polynuclear aromatic containing coal tar having an initial
mutagenicity index value greater than zero with an alkylating
agent in the presence of an acid catalyst under alkylation
conditions to introduce an branched chain alkyl group of three
to five carbon atoms into the polynuclear aromatic compounds
to reduce the mutagenicity of the polynuclear aromatic
containing
coal tar to a level less than the initial mutagenicity index
value.
The references of record relied upon by the examiner are:
Rehner et al. (Rehner) 2,833,834 May 6, 1958
Longwell et al. (Longwell) 4,409,094 October 11,
1983
Wise 3,251,897 May 17,
1966
Wadlinger et al. (Wadlinger) 3,308,069 March 7,
1967
Rubin et al. (Rubin) 4,954,325 September 4,
1990
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