Oxalic acid dimethyl ester

Acetic acid, methyl ester Acetic acid, ethyl ester Pentanoic acid, methylethyl ester Acetic acid, methylethyl ester Acetic acid, 3-propenyl ester Acetic acid, benzyl ester Oxalic acid, dimethyl ester Oxalic acid, diethyl ester Oxalic acid, fe(l-methylethyl) ester... 

Oxalic acid, dimethyl ester Me0C(0)C(0)0CH2—H 403.9... 

Butanoic acid, 4-hydroxylactone 12.6 Oxalic acid, dimethyl ester II.O... 

Oxalic acid dimethyl ester (CH3C(0)0)2 96.5 403.8 Correlation 2000DEN/DEN... 

The treatment of kasuganobiosamine with dimethyl ester of oxalic acid followed by concentrated aqueous ammonia gave two kinds of amides. The amide (11a) with pK a 7.6 was identical with the amide of kasugamycinic acid, which was prepared from kasugamycinic acid by treatment with anhydrous hydrogen chloride-methanol followed by concentrated aqueous ammonia. The other isomer (lib) with pK a 7.8, was named amide of isokasugamycinic acid. 

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... 

L-dihydroxy-succinic acid (L(dexiro)-tartaric acid, CXIII). This result establishes the position of the double bond between C4 and C5 and demonstrates that C4 carries only one hydrogen atom while C5 has attached to it the enolic hydroxyl group. Treatment of the enol CXI with ethereal diazomethane gives 5-methyl-A4-D-glucosaccharo-3,6-lactone methyl ester (CXIY) which upon further methylation with silver oxide and methyl iodide yields 2,5-dimethyl-A4-D-glucosaccharo-3,6-lactone methyl ester (CXV). When the latter is subjected to ozonolysis there is formed oxalic acid and 3-methyl-L-threuronic acid (CXVI). Oxidation of this aldehydic acid (CXYI) with bromine gives rise to a monomethyl derivative (CXVII) of L-ilireo-dihydroxy-succinic acid. 

Dialkyl Oxalates. Oxalic acid gives various esters, Dialkyl esters ROOC—COOR, are industrially useful, but monoalkyl esters, ROOC— COOH, are not The dialkyl esters are characterized by good solvent properties and serve as starting materials in the synthesis of many organic compounds, such as pharmaceuticals, agrochemicals, and fine chemicals (qv). Among die dieslers, dimethyl, diediyl. and di-n-butyloxalates are industrially important. 

Reaction CII. Direct Action of an Acid on an Alcohol. (A. Ch., 58, 44.) —Few normal esters are prepared in this way—dimethyl oxalate being an exception in this case the water formed is probably prevented from including the back reaction by the presence of anhydrous oxalic acid—but the yield is only 40%. With acid esters, however, good yields can be obtained, since only partial esterification is required. 

Electrolysis of a methanol solution of methyl oxalate with ethylene under pressure yielded 70-90% of the dimethyl esters of succinic, adipic, suberic, and sebacic acids. Decrease in the ethylene pressure or increase of the current density led to a decrease in the higher esters in the product mixture [241]. The influence of mechanism and kinetic data on yields and selectivities in addition reactions of anodically generated radicals to olefins has been calculated and predictions have been tested in preparative electrolyses [244]. 

Oxalic acid shows many of the reactions which are characteristic of compounds containing the carboxyl group. It forms esters and other compounds. Dimethyl oxalatej (COOCH3) 2, which melts at 54°, can be made by heating together methyl alcohol and anhydrous oxalic acid. It is sometimes used to prepare pure methyl alcohol free from acetone (see section 53). The ester is first purified by crystallization, and then heated with water or a solution of an alkali, when it is converted into methyl alcohol and oxalic acid or an oxalate. 

For example, hydrolysis of esters of dicarboxylic acids belongs to such reactions. Thus, dimethyl ester of the oxalic acid is hydrolyzed through two steps... 

Gaenzler, Klaus and Schroeder report [222] that esters of oxalic acid can be produced in 90% selectivity at 60-70 C at 120 atmospheres pressure. In a typical reaction for dimethyl oxalate synthesis, an autoclave is charged with PdCl2 (1.5 g), DCl (0.75 g), anhydrous CuCU (10 g) and methanol (400g). The reactor (one-fourth filled) is pressurized with CO (100 atm.) and O2 (20 atm.) and warmed to 60 C. An exothermic reaction ensues and 37 g of dimethyl oxalate are distilled from the reaction mixture. The selectivity to the ester is 90% and the yield based on CO charged to the reactor is 9.65%. 

More recently, Ube Industries have published an indirect process to carbonylate methanol oxidatively to dimethyl oxalate utilizing nitrous acid methyl ester as the oxidant. A supported Pd/Fe catalyst is used and methyl nitrite can be generated either in situ or in a separate reactor from methanol and NO [74] ... 

The above example serves to iUustrate the basis of the procedure employed for the characterisation of aUphatic esters, viz., hydrolysis to, and identification of, the parent acids and alcohols. Most esters are liquids a notable exception is dimethyl oxalate, m.p. 54°. Many have pleasant, often fruit-hke, odours. Many dry esters react with sodium, but less readily than do alcohols hydrogen is evolved particularly on warming, and a sohd sodio derivative may separate on coohng (e.j/., ethyl acetate yields ethyl sodioacetoacetate ethyl adipate gives ethyl sodio cj/cZopentanone carboxylate). 

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