Methyl alcohol carboxylation

Esters can participate m hydrogen bonds with substances that contain hydroxyl groups (water alcohols carboxylic acids) This confers some measure of water solubil ity on low molecular weight esters methyl acetate for example dissolves m water to the extent of 33 g/100 mL Water solubility decreases as the carbon content of the ester increases Fats and oils the glycerol esters of long chain carboxylic acids are practically insoluble m water... 

Carbon Cha.in Backbone Polymers. These polymers may be represented by (4) and considered derivatives of polyethylene, where n is the degree of polymeriza tion and R is (an alkyl group or) a functional group hydrogen (polyethylene), methyl (polypropylene), carboxyl (poly(acryhc acid)), chlorine (poly(vinyl chloride)), phenyl (polystyrene) hydroxyl (poly(vinyl alcohol)), ester (poly(vinyl acetate)), nitrile (polyacrylonitrile), vinyl (polybutadiene), etc. The functional groups and the molecular weight of the polymers, control thek properties which vary in hydrophobicity, solubiUty characteristics, glass-transition temperature, and crystallinity. 

The most important derivatives of the carboxyl group are formed by esterification with monohydric or polyhydric alcohols. Typical alcohols used iaclude methyl alcohol, ethylene glycol, glycerol, and pentaerythritol. These rosia esters have a wide range of softening poiats and compatibiUties. 

The most common impurities are the corresponding acid and hydroxy compound (i.e. alcohol or phenol), and water. A liquid ester from a carboxylic acid is washed with 2N sodium carbonate or sodium hydroxide to remove acid material, then shaken with calcium chloride to remove ethyl or methyl alcohols (if it is a methyl or ethyl ester). It is dried with potassium carbonate or magnesium sulfate, and distilled. Fractional distillation then removes residual traces of hydroxy compounds. This method does not apply to esters of inorganic acids (e.g. dimethyl sulfate) which are more readily hydrolysed in aqueous solution when heat is generated in the neutralisation of the excess acid. In such cases, several fractional distillations, preferably under vacuum, are usually sufficient. 

One of the most useful ways of introducing fluorine into organic compounds is the placement of the hydroxyl group in alcohols hydroxy compounds, and carboxylic acids Methyl alcohol reacts with anhydrous hydrogen fluoride at 100 500 °C in the presence of aluminum fluoride [60, 61], zinc fluoride [62] chromium fluonde [63], or a mixture of aluminum and chromium fluondes [64] to give a 20-78% yield of fluoromethane Attempted fluorinations of higher alcohols by this method failed [60]... 

This derivative is prepared from an A-protected amino acid and the anthryl-methyl alcohol in the presence of DCC/hydroxybenzotriazole. It can also be prepared from 2-(bromomethyl)-9,10-anthraquinone (Cs2C03). It is stable to moderately acidic conditions (e.g., CF3COOH, 20°, 1 h HBr/HOAc, t,/, = 65 h HCI/CH2CI2, 20°, 1 h) Cleavage is effected by reduction of the quinone to the hydroquinone i in the latter, electron release from the -OH group of the hydro-quinone results in facile cleavage of the methylene-carboxylate bond. 

The nitrile may best be saponified with methyl alcoholic potash while heating to 190° to 200°C with application of pressure. After the methyl alcohol has evaporated the salt is introduced into water and by the addition of dilute mineral acid until the alkaline reaction to phenolphthalein has just disappeared, the amphoteric 1-methyl-4-phenyl-piperidine-4-carbOxylic acid is precipitated while hot in the form of a colorless, coarsely crystalline powder. When dried On the water bath the acid still contains 1 mol of crystal water which is lost only at a raised temperature. The acid melts at 299°C. Reaction with ethanol yields the ester melting at 30°C and subsequent reaction with HCI gives the hydrochloride melting at 187° to 188°C. 

PET is the polyester of terephthalic acid and ethylene glycol. Polyesters are prepared by either direct esterification or transesterification reactions. In the direct esterification process, terephthalic acid is reacted with ethylene glycol to produce PET and water as a by-product. Transesterification involves the reaction of dimethyl terephthalate (DMT) with ethylene glycol in the presence of a catalyst (usually a metal carboxylate) to form bis(hydroxyethyl)terephthalate (BHET) and methyl alcohol as a by-product. In the second step of transesterification, BHET... 

Carboxylic acids can be converted to esters with diazo compounds in a reaction essentially the same as 10-15. In contrast to alcohols, carboxylic acids undergo the reaction quite well at room temperature, since the reactivity of the reagent increases with acidity. The reaction is used where high yields are important or where the acid is sensitive to higher temperatures. Because of availability, the diazo compounds most often used are diazomethane (for methyl esters) ... 

The main drawback to this reaction is the toxicity of diazomethane and some of its precursors. Diazomethane is also potentially explosive. Trimethylsilyldia-zomethane is an alternative reagent,42 which is safer and frequently used in preparation of methyl esters from carboxylic acids.43 Trimethylsilyldiazomethane also O-methylates alcohols.44 The latter reactions occur in the presence of fluoroboric acid in dichloromethane. 

Diphenyl diselenide di-p-carboxylic acid, Se2(C6H4.C02H)2, is formed in the usual way from -aminobenzoic acid. It melts at 314° to 315° C., is only sparingly soluble in acetic acid, but may be crystallised from methyl alcohol. The yield is poor. 

Trinitroanisol may also be prepared by the interaction of methyl iodide and silver picrate, and by the nitration of anisic acid, during which the carboxyl group is lost, but the most convenient method appears to be that of Jackson70 and his collaborators by which a methoxy group is substituted for chlorine in a nucleus already nitrated. A methyl alcohol solution of picryl... 

Whereas the C2—C4 alcohols are not carboxylated under the usual Koch-Haaf conditions, carboxylation can be achieved in the HF-SbF5 superacid system under extremely mild conditions.400 Moreover, Olah and co-workers401 have shown that even methyl alcohol and dimethyl ether can be carboxylated with the superacidic HF-BF3 system to form methyl acetate and acetic acid. In the carboxylation of methyl alcohol the quantity of acetic acid increased at the expense of methyl acetate with increase in reaction time and temperature. The quantity of the byproduct dimethyl ether, in turn, decreased. Dimethyl ether gave the desired products in about 90% yield at 250°C (90% conversion, catalyst/substrate ratio =1 1, 6h). On the basis of experimental observations, first methyl alcohol is dehydrated to dimethyl ether. Protonated dimethyl ether then reacts with CO to yield methyl acetate [Eq. (5.154)]. The most probable pathway suggested to explain the formation of acetic acid involves the intermediate formation of acetic anhydride through acid-catalyzed ester cleavage without the intervention of CO followed by cleavage with HF [Eq. (5.155)]. 

GC analysis of underivatized polar fractions did not reveal any volatile sulfur compounds. However, once these fractions were methylated with diazomethane, a number of sulfur compounds were detected. (Presumably, the diazomethane methylated either carboxylic acid, phenolic, thiophenolic, sulfonic acid or even alcohol or thiol groups and thereby increased their parent molecules volatility). These additional sulfur compounds are currently under investigation in our laboratories and the results of these studies will be reported later. 

Other organic compounds that have been determined in sewage effluents include the following (see Table 15.13) hydrocarbons, alcohols, carboxylic acids, esters, chlorobenzenes, nitrosamines, ethylene diamine tetraacetic acid, nitriloacetic acid, organophosphorus compounds, linear alkyl benzene sulphonates, methyl mercaptan, polychlorobiphenyls and chlorinated insecticides. 

In the presence of alkyl halides and base, alkyltetracarbonylcobalt complexes are formed with Co2(CO)8 these species [RCo(CO)4] carbonylate a wide range of aryl halides or heterocyclic halides to various products, which depend upon the specific conditions. In the presence of alcohols, carboxylic esters are formed. Under phase transfer conditions and with iodomethane, mixtures of methyl ketone and carboxylic acid formation are realized (equation 207). In the presence of sodium sulfide or NaBH4 in water-Ca(OH)2 (equation 208) good amounts of double carbonylation are realized under very mild conditions412-414. 

The general nature of the reaction is that the carboxyl group is replaced by hydroxyl, so that an alcohol is formed having one carbon atom less than the acid thus methyl alcohol is obtained from acetic acid ... 

Sodium succinate and sodium perchlorate, electrolyzed, by Hofer and Moest,2 gave hydracrylic acid as the chief product, besides acetaldehyde, acetic acid, methyl alcohol, and formic acid. The splitting off of carbonic acid and the introduction of the hydroxyl group occurs only at one carboxyl group ... 

To 1-aminocyclohexane-l-carboxylic acid (350 mmol) dissolved in 1.25 L of methyl alcohol in a glass reactor was added 51 ml thionyl chloride in portions at —5°C. The mixture was stirred 5 hours then stood overnight. Thereafter, the mixture was concentrated, the residue mixed with water, the solution pH adjusted to 9 using Na2C03, and extracted twice with CH2CI2. The organic phase was dried, re-concentrated, and the product isolated in 66% yield. 

A solution of 3,5-dichloro-2-(2-(4-morpholinyl)-ethoxy)pyridine-4-carboxylic acid (0.01 mol) and cesium carbonate (0.015 mol) dissolved in 50 ml methyl alcohol was stirred 30 minutes. The solvent was then removed and the residue dissolved in 50 ml DMF. Thereafter, the product from Step 6 (0.01 mol) was added and the mixture heated to 80 °C 3 hours. The solvent was removed in vacuo, the residue dissolved in CH2CI2, then filtered through charcoal. DMF was again removed, the residue dissolved in t-butyl-methylether, concentrated, and the residue treated with ethereal HCl. A gum was obtained which was triturated with acetonitrile and the product isolated in 9% yield, mp = 120-140°C. 

Phenylarsine-p-carboxylic acid, CO2H.C6H4.AsH2. —A methyl alcohol solution of p-carboxyphenylarsinic acid is reduced by zinc dust and hydrochloric acid and the product removed by steam distillation. In the moist state it is very sensitive to atmospheric oxygen, becoming yellow and apparently dianging to p-arsenobenzoic acid. 

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