Methyl ethyl ketone hydroperoxide

METHYL-4 -ETHYLIDENE-THIOSEMICARBAZIDO)ACRIDINE see MKr 300 METHYL ETHYL KETONE see MKA400 METHYL ETHYL KETONE HYDROPEROXIDE see MKA500... 

MEKP or MEK PEROXIDE or MEKP-HA 1 or MEKP-LA 1 (1338-23-4) see methyl ethyl ketone hydroperoxide. MELINITE (88-89-1) see picric acid. MELIPAX (8001-35-2) see toxaphene. MENDRIN (72-20-8) see endrin. MENIPHOS or MENITE (7786-34-7) see MEVINPHOS . 

THERMACURE (1338-23-4) see methyl ethyl ketone hydroperoxide. THERMALOX (1304-56-9) see beryllium oxide. 

Synonyms/Trade Names 2-Butanone peroxide, Ethyl methyl ketone peroxide, MEKP, MEK peroxide. Methyl ethyl ketone hydroperoxide ... 

The most commonly used initiator for anaerobic adhesives is cumene hydroperoxide. Many other hydroperoxides have been disclosed, such as t-butylhydroperoxide (XL), p-menthane hydroperoxide (XLI), diisopropylbenzene hydroperoxide (XLII), pinene hydroperoxide (XLIII), and methyl ethyl ketone hydroperoxide (XLIV) [40]. Some diperoxides, such as di-/-butylperoxide (XLV) and dicumylperoxide (XLVI), have been claimed, but these may function only because of hydroperoxide contamination [41]. 

The allergens in UP resin are often the auxiliary chemicals in the resin, such as cobalt naphthenate (Key et al. 1961 Bourne and Milner 1963 Malten and Ziehlhuis 1964 Kadlec et al. 1974), dibutyl phthalate, dimethyl phthalate, dioctyl phthalate (Malten and Ziehlhuis 1964), tricresyl phosphate (Key et al. 1961) or a cross-linking monomer, such as styrene (Key et al. 1961 Bourne and Milner 1963 Meneghini et al. 1963 Sjoborg et al. 1982 Conde-Salazar et al. 1989) or a hardening catalyst such as benzoyl peroxide (Bourne and Milner 1963 Malten and Ziehlhuis 1964 Vincenzi et al. 1991), cyclohexanone hydroperoxide (Malten 1964) or methyl ethyl ketone hydroperoxide (Bourne and Milner 1963 Malten and Ziehlhuis 1964). The... 

The most commonly used initiator for anaerobic adhesives is cumene hydroperoxide (CHP). Many other hydroperoxides have been disclosed such as /erf-butyl hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, pinene hydroperoxide and methyl ethyl ketone hydroperoxide [160]. 

Derivative Formation. Hydrogen peroxide is an important reagent in the manufacture of organic peroxides, including tert-huty hydroperoxide, benzoyl peroxide, peroxyacetic acid, esters such as tert-huty peroxyacetate, and ketone derivatives such as methyl ethyl ketone peroxide. These are used as polymerization catalysts, cross-linking agents, and oxidants (see Peroxides and peroxide compounds). 

The gas approximates plug flow except in wide columns, but the liqiiid undergoes considerable oa mixiug. The latter effect can be reduced with packing or perforated plates. The effect on selectivity may become important. In the oxidation of hquid /i-butane, for instance, the ratio of methyl ethyl ketone to acetic acid is much higher in plug flow than in mixed. Similarly, in the air oxidation of isobutane to tei t-huty hydroperoxide, where te/ t-butanol also is obtained, plug flow is more desirable. 

For a number of applications curing at room temperature is desirable. This so-called cold cure is brought about by using a peroxy initiator in conjunction with some kind of activator substance. The peroxy compounds in these cases are substances such as methyl ethyl ketone peroxide and cyclohexanone peroxide, which as used in commercial systems tend not to be particularly pure, but instead are usually mixtures of peroxides and hydroperoxides corresponding in composition approximately to that of the respective nominal compounds. Activators are generally salts of metals capable of undergoing oxidation/reduction reactions very readily. A typical salt for this purpose is cobalt naphthenate, which undergoes the kind of reactions illustrated in Reactions 4.6 and 4.7. 

Dimethyl peroxide Diethyl peroxide Di-t-butyl-di-peroxyphthalate Difuroyl peroxide Dibenzoyl peroxide Dimeric ethylidene peroxide Dimeric acetone peroxide Dimeric cyclohexanone peroxide Diozonide of phorone Dimethyl ketone peroxide Ethyl hydroperoxide Ethylene ozonide Hydroxymethyl methyl peroxide Hydroxymethyl hydroperoxide 1-Hydroxyethyl ethyl peroxide 1 -Hydroperoxy-1 -acetoxycyclodecan-6-one Isopropyl percarbonate Isopropyl hydroperoxide Methyl ethyl ketone peroxide Methyl hydroperoxide Methyl ethyl peroxide Monoperoxy succinic acid Nonanoyl peroxide (75% hydrocarbon solution) 1-Naphthoyl peroxide Oxalic acid ester of t-butyl hydroperoxide Ozonide of maleic anhydride Phenylhydrazone hydroperoxide Polymeric butadiene peroxide Polymeric isoprene peroxide Polymeric dimethylbutadiene peroxide Polymeric peroxides of methacrylic acid esters and styrene... 

When C4H80 is diluted by water to 80 volume %, the only product of C4H80 oxidation is acetic acid (99% per methyl ethyl ketone reacted) formed by ketone hydroperoxide conversion. The reason for this increase in the reaction selectivity is that the rate of decomposition of the radical complex R02. . . HOH is lower than that of free R02, while the decrease in the rate of reaction of R02. . . HOH with methyl ethyl ketone is somewhat offset by the higher dielectric constant of the medium. 

The slow combustion reactions of acetone, methyl ethyl ketone, and diethyl ketone possess most of the features of hydrocarbon oxidation, but their mechanisms are simpler since the confusing effects of olefin formation are unimportant. Specifically, the low temperature combustion of acetone is simpler than that of propane, and the intermediate responsible for degenerate chain branching is methyl hydroperoxide. The Arrhenius parameters for its unimolecular decomposition can be derived by the theory previously developed by Knox. Analytical studies of the slow combustion of methyl ethyl ketone and diethyl ketone show many similarities to that of acetone. The reactions of methyl radicals with oxygen are considered in relation to their thermochemistry. Competition between them provides a simple explanation of the negative temperature coefficient and of cool flames. 

Low Temperature Reaction. Reaction in the low temperature regime below 320°C. is of a different character. The products include carbon dioxide and significant quantities of peroxy compounds, as well as carbon monoxide, water, formaldehyde, and methanol, but methane and ethylene are formed only in traces. The peroxy compounds comprise hydrogen peroxide from all three ketones, methyl hydroperoxide from acetone (8) and methyl ethyl ketone (I), and ethyl hydroperoxide from diethyl ketone (1). Methyl ethyl ketone also gives large amounts of peracetic acid (1). 

Figure 6 shows the variation of peroxide concentration in methyl ethyl ketone slow combustion, and similar results, but with no peracid formed, have been found for acetone and diethyl ketone. The concentrations of the organic peroxy compounds run parallel to the rate of reaction, but the hydrogen peroxide concentration increases to a steady value. There thus seems little doubt that the degenerate branching intermediates at low temperatures are the alkyl hydroperoxides, and with methyl ethyl ketone, peracetic acid also. The tvfo types of cool flames given by methyl ethyl ketone may arise from the twin branching intermediates (1) observed in its combustion. 

Ketone Peroxides. These materials are mixtures of compounds with hydroperoxy groups and are composed primarily of the two structures shown in Table 2. Ketone peroxides are marketed as solutions in inert solvents such as dimethyl phthalate. They are primarily employed in room-temperature-initiated curing of unsaturated polyester resin compositions (usually containing styrene monomer) using transition-metal promoters such as cobalt naphthenate. Ketone peroxides contain the hydroperoxy (—OOH) group and thus are susceptible to the same hazards as hydroperoxides. By far the most popular commercial ketone peroxide is methyl ethyl ketone peroxide [1338-23-4]. Smaller quantities of ketone peroxides such as methyl isobutyl ketone peroxide [28056-59-9], cyclohexanone peroxide [12262-58-7], and 2,4-pentanedione peroxide [37187-22-7] are used commercially (47). 

Other peroxides—2,6-dichlorobenzoyl peroxide lauroyl peroxide, tert-butyl hydroperoxide, and methyl ethyl ketone peroxide—are also highly effective for the free radical reaction at low temperatures. On the other hand, azobisisobutyronitrile (AIBN) is ineffective. Hence, the mechanism cannot be simple, free radical formation which then initiates polymerization. 

Concurrently, the hydroperoxide may be converted to methyl ethyl ketone (MEK). If the initial radical attack is at the primary rather than the secondary carbon, the process makes propionic and formic acids. Reaction conditions can be changed to produce more MEK at the expense of some acetic acid. The maximum acetic acid/MEK ratio is 6.5-7 on a weight basis. If ethyl acetate is also formed, the ratio can go down to acetic acid/(ethyl acetate + MEK) of 3.6-4, with MEK being about 55 percent of the byproduct. 

Splitting of 2-phenyl butane hydroperoxide into phenol and methyl ethyl ketone, this intermediate being itself obtained by the alkylation of benzene by means of n-butenes... 

Oxidation of methyl ethyl ketone at 100—145° C under pressure has been studied in detail [123], The intermediate products of this reaction are hydroperoxide and diacetyl, and the main oxidation products are acetic acid and ethyl acetate. The sequence of processes is... 

Many peroxides affect pol mierization, but those used are available in quantity and the choice is based both on economics and performance. It has been shown that the activity of the organic peroxides in any polymerization is related to their decomposition rates at various temperatures. If elevated cure temperatures, 200- 250°F (93-121°C), are used, benzoyl peroxide is preferred. The amount required is about 1.0 per cent. It is preferred because a long catalyzed tank life results at room temperature. If lower temperatures in the 120 180 F (49-82°C) range are employed, hydroperoxides are more effective. Methyl ethyl ketone peroxide and cumene and ter- tiary butyl hydroperoxide all find application. Lauroyl peroxide, cyclohexanone peroxide, and <-butyl perbenzoate are used in limited amounts. Mixtures of two peroxides are often used, one to initiate the reaction and a second to promote the polymerization once it is started. 

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