Iodine monoxide, chemistry

Case Study V - Iodine monoxide chemistry in the coastal margins -Figure 23 shows the measured concentration of iodine monoxide (lO)... 

The halogen family, fluorine, chlorine, bromine, and iodine has only recently been introduced into atmospheric chemistry.9 The catalytic cycle, with an atom such as Cl in the presence of its monoxide CIO, can... 

The concept of co-carbonylation of methanol/methyl acetate mixtures was first introduced by BASF in the early 1950s, but the reaction chemistry was not fully developed to commercial realization [75]. Not until the mid-1980s, after the development of carbonylation processes to produce acetic acid and acetic anhydride, were co-carbonylation processes patented using homogeneous rhodium/iodine catalyst systems (Table 2) [2, 56]. The basic process concept is to manufacture acetic acid and acetic anhydride from methanol and carbon monoxide as the only raw materials and to generate methyl acetate within the process. Similiarly, the suitability of dimethyl ether as a raw material for the generation of the anhydride equivalent in addition to or as a substitute for methyl acetate was revealed by Hoechst [76]. To produce a small fraction of acetic acid besides acetic anhydride as the main product, the carbonylation of methyl acetate could be conducted with small amounts of water or methanol. This variant, first demonstrated by Hoechst [56], is practiced by Eastman Kodak [2]. 

Up until the end of the 1980s, radical carbonylation chemistry was rarely considered to be a viable synthetic method for the preparation of carbonyl compounds. In recent years, however, a dramatic change has occurred in this picture [3]. Nowadays, carbon monoxide has gained widespread acceptance in free radical chemistry as a valuable Cl synthon [4]. Indeed, many radical methods can allow for the incorporation of carbon monoxide directly into the carbonyl portion of aldehydes, ketones, esters, amides, etc. Radical carboxylation chemistry which relies on iodine atom transfer carbonylation is an even more recent development. In terms of indirect methods, the recent emergence of a series of sulfonyl oxime ethers has provided a new and powerful radical acylation methodology and clearly demonstrates the ongoing vitality of modem free radical methods for the synthesis of carbonyl compounds. 

Chemistry of Acetic Acid by Carbonylation. Two processes have been commercialized for the carbonylation of methanol to acetic acid. BASF understood the possibility of a methanol and carbon monoxide process for acetic acid, using a cobalt- and iodine-based catalyst, since the early 1920s. But development was held back by the lack of suitable construction materials for the severe operating conditions and corrosive environment necessary. The operating temperature is 250°C (482 F) and the required pressure is 680 bars (10,000 psig). In the late 1950s, development of molyb-... 

Iodine pentoxide, I2O5, is the most stable oxide of the halogens [8]. It has found some practical application as a mild oxidant, especially useful in analytical chemistry. Iodine pentoxide is one of the few chemicals that can oxidize carbon monoxide rapidly and completely at room temperature. The reaction forms the basis of a useful analytical method for determining the concentration of CO in the atmosphere or in other gaseous mixtures [8]. 

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