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Dimethyl oxalate can be converted into ethylene glycol in high yields (94.7%) [10] [11] The methanol formed is recycled in the process of oxidative carbonylation. [12] Other plants with a total annual capacity of more than 1 million tons of ethylene glycol per year are planned. Decarbonylation gives dimethyl carbonate. [13]
Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula C 2 O 2− 4. This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na 2 C 2 O 4), and several esters such as dimethyl oxalate ((CH 3) 2 C 2 O 4). It is a conjugate base of oxalic acid.
Another process uses oxygen to regenerate the nitric acid, using a variety of precursors including glycolic acid and ethylene glycol. [17] As of 2011, this process was only used by Mitsubishi in Japan. [18] A newer method entails oxidative carbonylation of alcohols to give the diesters of oxalic acid: 4 ROH + 4 CO + O 2 → 2 (CO 2 R) 2 + 2 H 2 O
Oxaloacetic acid (also known as oxalacetic acid or OAA) is a crystalline organic compound with the chemical formula HO 2 CC(O)CH 2 CO 2 H. Oxaloacetic acid, in the form of its conjugate base oxaloacetate, is a metabolic intermediate in many processes that occur in animals.
The chemical reactions of dimethylacetamide are typical of N,N-disubstituted amides. Hydrolysis of the acyl-N bond occurs in the presence of acids: . CH 3 CON(CH 3) 2 + H 2 O + HCl → CH 3 COOH + (CH 3) 2 NH 2 + Cl −
The first step of the synthesis is the condensation of o-nitrotoluene 1 with a diethyl oxalate 2 to give ethyl o-nitrophenylpyruvate 3. The reductive cyclization of 3 with zinc in acetic acid gives indole-2-carboxylic acid 4. If desired, 4 can be decarboxylated with heat to give indole 5.
Oxalyl chloride was first prepared in 1892 by the French chemist Adrien Fauconnier, who treated diethyl oxalate with phosphorus pentachloride. [5] It can also be prepared by treating oxalic acid with phosphorus pentachloride. [6] [7] Oxalyl chloride is produced commercially from ethylene carbonate.
The by-products are dimethyl sulfide ((CH 3) 2 S), carbon monoxide (CO), carbon dioxide (CO 2) and—when triethylamine is used as base—triethylammonium chloride (Et 3 NHCl). Of the volatile by-products, dimethyl sulfide has a strong, pervasive odour and carbon monoxide is acutely toxic, so the reaction and the work-up needs to be performed ...