This paper reports an investigation on the Bunsen reaction. An experimental campaign was conducted by means of a stirred reactor. Runs were carried out at a constant temperature in the 30-120 degrees C range, following a semi-batch procedure by feeding gaseous sulfur dioxide in an iodine/hydriodic acid/water solution. A specific analytical procedure to measure the hydriodic phase composition was implemented. It was observed that both the amount of absorbed SO(2) and its conversion lowered as the temperature increased. Secondary reactions were beyond the detection limit in the reactor, even at low temperature and low iodine content. The purification of the produced hydriodic phase was also investigated. It was possible to satisfactorily reduce the impurities content without the occurrence of secondary reactions only when high temperature and high iodine content were applied. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.