Abstract
In order to assess, and possibly find a method of reducing, the explosion huard in the manufacture of acetic acid from acetalde‐hyde, a knowledge was required of the range of acctaldehyde‐oxygen‐nitrogen mixtures capable of propapating flame under wrious conditions. The limits of inflammability in such mixtures were therefore determined for upward, horizontal and downward !lame‐propagation in glass tubes of I‐, 2‐ and 3‐in. diameter at room temperature and at so^o^ C. The effect of contamination with carbon dioxide, acetylene and acetic acid was also examined, as well as that of using aluminium tubes in place of glass. The range of inflammability in the acetaldehydroxygen‐nitrogen system is exceptionally wide and offers little hope of eliminating explosion risks in the manufacture of acetic acid, the best safeguard being to minimize free space and place suitable guards at vulnerable points.
The results show that in acetaldehydc∼∼gen‐nitrogen mixmres, the lower limit is mainly a function of the acetaldehyde content, whereas the upper limit is mainly determined by the oxygen content; this suggests that the calorific value Of the gas is an important factor in limit propagation. Another important factor in the case of acetaldehyde is the apearancc of the ‘cool’ flame. This causes a marked extension of t!e upper limit, from which it is inferred that the products of ‘cool’ flame combustion are incompletly oxidized, the main constituent being possibly acetic acid.