Kinetics and mechanism of iodination of 1-methylpyrazole

A spectrophotometric method was used to determine the rate law in buffered aqueous iodine-iodide solutions. Three iodinating agents other than iodine were considered: direct attack by hypoiodous acid, acid catalyzed attack by hypoiodous acid, and the iodinium ion. The first two were discarded because of the observed dependence of the rate on the buffer concentration and the observed independence of the rate on the hydrogen ion concentration. The postulated mechanism is in agreement with the mechanisms for aniline and pyrazole. The rate determining step is the removal of the proton from the intermediate by the buffer. However, it was found that iodine was the major iodinating species and that the iodinium ion had a much smaller effect. A qualitative discussion of the reactivities of pyrazole, J-methylpyrazole., and l-methylpyrazole was made. An attempt was made to show possible reasons for the observed results.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Polytechnic Institute

Year dc:date.issued

1962

Author dc:creator

• Jewett, Gary Lew

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/104500

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/104500