Methyl large-scale oxidation

The oxidative cleavage by the procedure of Lemieux (9) was not convenient on a large scale due to the dilute reaction conditions, (7.5 L of 2 1 water 2-methyl-2-propanol) and the need for nine equivalents of relatively expensive sodium metaperiodate... 

Chlorinated derivatives of methane include methyl chloride, methylene chloride, chloroform, carbon tetrachloride, and several chlorofluorohydrocarbons (CFCs). We discuss carbon tetrachloride (CT) as a representative example of this group. CT was originally prepared in 1839 and was one of the first organic chemicals to be produced on a large scale by the end of the nineteenth century and beginning of the twentieth century. CT is the most toxic of the chloromethanes and the most unstable on thermal oxidation (Holbrook 2000). 

Abstract This chapter covers oxidation of C-H and C-C bonds in alkanes. Section 4.1 concerns oxidation of C-H bonds aldehydes and other CH species (4.1.1), methylene (-CH groups) (4.1.2) and methyl (-CH ) groups (4.1.3). This is followed by the oxidation of cyclic alkanes (4.1.4) and large-scale alkane oxidations (4.1.5). Alkane oxidations not considered here but covered in Chapter 1 are hsted in Section 4.1.6. The final section (4.2) concerns oxidative cleavage of C-C bonds. 

Galactose oxidase (EC 1.1.3.9), which catalyzes the oxidation of D-galac-tose (and derivatives) to D-gu/ucm-hexodialdose (and derivatives), is useful for analytical determinations,388 but is not an efficient method for large-scale preparation of methyl D-ga/ucm-hexodialdo-l,5-pyranosides. The fi anomer of the latter was characterized as a dimeric hexaacetate.389... 

We describe in detail the syntheses of digermoxane and its methyl analogues from the reaction of lead(II) oxide with bromogermanes. The procedures are convenient and well suited to large-scale preparations in a relatively short time (about 1 hr), using a minimum of special apparatus. The yields are in the range 87-98%. 

The conversion of alkenes to oxiranes using ketone catalysts in the presence of a terminal oxidant such as Oxone has proved to be an important advance in the past decade, especially for the formation of chiral oxiranes (see Section 1.03.4.3.3(ii)). The conversion of alkenes to oxiranes has been comprehensively reviewed <20020R219>. The formation of the dioxirane species usually proceeds in situ, whether it be the formation of methyl(trifluoromethyl)-dioxirane in an academic setting <1995JOC3887>, or under conditions amenable to large-scale conversion of aromatic alkenes to oxiranes (oxone, acetone, ethyl acetate, no phase-transfer catalysis) <20020PD405>. 

The importance of isobutylene in the petrochemical industry is well recognized. Isobutylene is used on a large scale for the production of (i) methacrolein by direct oxidation, (ii) polyisobutylene by polymerization, (iii) synthetic rubber (a copolymer of isobutylene and isoprene), and (iv) methyl tert-butyl ether (MTBE, a gasoline octane-number enhancer) by reaction with methanol. 

Such reactions take place with p-xylene [28], ethylbenzene [28], and especially readily with isopropylbenzene (cumene) [29], where the intermediate free radical is stabilized not only by the aromatic ring but also by the two adjacent methyl groups. The oxidation of cumene to cumyl hydroperoxide (equation 162) followed by acid treatment is a basis for the large-scale production of phenol. 

---