Methyl iodide, formation

The two catalyst components are rhodium and iodide, which can be added in many forms. A large excess of iodide may be present. Rhodium is present as the anionic species RhI2(CO)2. Typically the rhodium concentration is 10 mM and the iodide concentration is 1.5 M, of which 20% occurs in the form of salts. The temperature is about 180 °C and the pressure is 50 bar. The methyl iodide formation from methanol is almost complete, which makes the reaction rate also practically independent of the methanol concentration. In other words, at any conversion level (except for very low methanol levels) the production rate is the same. For a continuous reactor this has the advantage that it can be operated at a high conversion level. As a result the required separation of methanol, methyl acetate, methyl iodide, and rhodium iodide from the product acetic acid is much easier. 

Habersbergerova, A. Investigation of the possibility of radiation-induced methyl iodide formation under operating conditions of PWR reactors. Radiat. Phys. Chem. 34, 781-785... 

When the methyl-phenyl-pyrazolone is heated with methyl iodide in methano-lie solution, it acts in the form (D), the — NH— group undergoing methy lation, with the formation of the hydriodide of 2,3-dimethyl- l-phenyl-5 Pyrazolone, or antipyrine (F), a drug used (either as the free base or as the... 

Methiodide formation. Place 2 drops of dry pyridine in a dry test-tube, add 4-5 drops of methanol, and 2 -3 drops of methyl iodide. 

If the temperature is allowed to rise, the yield is slightly diminished owing to the formation of a little methyl iodide. 

Methoxythiazoles are converted to the corresponding N-methyl-A-4-thiazoline-2-ones by heating with excess methyl iodide (29, 243). The reaction mechanism can be considered initially as the formation of a... 

It looks as though all that is needed is to prepare the acetylenic anion then alkylate it with methyl iodide (Section 9 6) There is a complication however The carbonyl group m the starting alkyne will neither tolerate the strongly basic conditions required for anion formation nor survive m a solution containing carbanions Acetyhde ions add to carbonyl... 

Barbier reported (1) in 1899 that a mixture of methyl iodide, a methyl ketone, and magnesium metal in diethyl ether produced a tertiary alcohol. Detailed studies by his student Victor Grignard are documented in his now classical doctoral thesis, presented in 1901. Grignard estabUshed (2) that the reaction observed by Barbier could be separated into three distinct steps Grignard reagent formation, Grignard reaction, and hydrolysis. 

Methyl chloride can be converted iato methyl iodide or bromide by refluxing ia acetone solution ia the presence of sodium iodide or bromide. The reactivity of methyl chloride and other aUphatic chlorides ia substitution reactions can often be iacteased by usiag a small amount of sodium or potassium iodide as ia the formation of methyl aryl ethers. Methyl chloride and potassium phthalimide do not readily react to give /V-methy1phtha1imide unless potassium iodide is added. The reaction to form methylceUulose and the Williamson synthesis to give methyl ethers are cataly2ed by small quantities of sodium or potassium iodide. 

Methyl ethyl ketone peroxide Methyl formate Methyl iodide Methyl isoamyl acetate Methyl isobutyl carbinol Methyl isobutyl ketone (hexone)... 

Isotope labeling by derivative formation with deuterated reagents is useful for the preparation of analogs such as dg-acetonides, da-acetates, da-methyl ethers, dg-methyl esters, etc. The required reagents are either commercially available or can be easily prepared. (The preparation of da-methyl iodide is described in section IX-F. Various procedures are reported in the literature for the preparation of dg-acetone, da-diazometh-ane57.i63.i73 and da-acetyl chloride. ) These reactions can be carried out under the usual conditions and they need no further discussion. A convenient procedure has been reported for the da-methylation of sterically hindered or hydrogen bonded phenolic hydroxyl functions by using da-methyl iodide and sodium hydroxide in dimethyl sulfoxide solution. This procedure should be equally applicable to the preparation of estradiol da-methyl ether derivatives. 

Primary halides are more reactive than secondary compounds quaternary salt formation does not occur with tertiary halides, elimination always occurring to give the hydriodide and an olefln, Also, the larger the alkyl group the slower is the reaction this is shown by the very slow reaction of dodecyl bromide with quinoline, and even butyl iodide is much slower to react than methyl iodide. The longer chain primary halides commonly undergo elimination rather than cause quaternization for example, n-octyl and cetyl iodides give only the hydriodides when heated with 9-aminoacridine. ... 

It is also interesting to note that quatemization of a chloropyrimi-dine at the nitrogen atom adjacent to the chloro group with methyl iodide results in the easy replacement of the chlorine by iodine, whereas similar salt formation on the remote nitrogen either leaves the chlorine unaffected or replacement occurs only at higher temperatures. A similar reaction occurs between 2-amino-6-chloro-4-methylpyrimidine and dimethyl sulfate in nitrobenzene to give the salt 45 and betaine 46. ... 

In a 1-substituted 1,2,3-triazole (79), both the 2- and 3-nitrogen atoms possess lone pairs of electrons that are available for quaternary salt formation, and quatemization is known to occur at the 3-nitrogen atom to give the symmetrical cation (80). Thus, the reaction between 1-methyl-l,2,3-triazole and benzyl iodide yields the same salt as is obtained from the interaction of 1-benzyl-1,2,3-triazole and methyl iodide the salt must therefore be 80 (R = Me, R = PhCH2,... 

The nitration of l,2,5-selenadiazolo[3,4-/] quinoline 77 with benzoyl nitrate affords the 8-nitro derivative 78, whereas methylation with methyl iodide or methyl sulfate afforded the corresponding 6-pyridinium methiodide 79 or methosulfate 80, respectively (Scheme 29). The pyridinium salt 80 was submitted to oxidation with potassium hexacyanoferrate and provided 7-oxo-6,7-dihydro derivative 81 or, by reaction of pyridinium salt 79 with phenylmagnesium bromide, the 7-phenyl-6,7-dihydro derivative 82. Nucleophilic substitution of the methiodide 79 with potassium cyanide resulted in the formation of 9-cyano-6,9-dihydroderivative 83, which can be oxidized by iodine to 9-cyano-l,2,5-selenadiazolo [3,4-/]quinoline methiodide 84. All the reactions proceeded in moderate yields (81IJC648). 

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