Diphenyl oxalate

The leaving group of the oxalic ester has a strong effect on the efficiency of the peroxyoxalate chemiluminescent system. The electron-attracting power of the substituents on the phenyl rings of the substituted diphenyl oxalates is important to the overall efficiency of the chemiluminescent reactions. Steric effects... 

We found that cyclic benzeneboronic anhydride (BBA), diphenyl carbonate (DPC) (4), diphenyl terephthalate (DPT) (5), diphenyl oxalate (DPO) (5), diphenyl malonate (DPM) (5), tetraphenyl orthocarbonate (POC) (6), hexaphenyl orthoterephthalate (POT) (7) are suitable compounds as chain extenders. 

The physical properties of PET obtained by the use of various additives are the same as those obtained by the conventional method (Table I). This fact indicates that the additive is not copolymerized into the polymer chain as a third component. Diphenyl oxalate, diphenyl mal-onate, hexaphenyl orthoterephthalate, tetraphenyl orthocarbonate, and phenyl triphenoxyacetate not only have a remarkable effect in increas-... 

Table III shows analytical values of the polymer prepared. The presence of a small amount of terminal acetyl group was found with diphenyl malonate and small amounts of terminal formyl groups with phenyl triphenoxyacetate and diphenyl oxalate. A trace of phenol...

Diphenyl Malonate and Diphenyl Oxalate. Above 200°C, the half ester of malonic acid decomposes to carbon dioxide and an ester of acetic acid, and the half ester of oxalic acid decomposes to carbon dioxide and an ester of formic acid. Diphenyl malonate and diphenyl oxalate are chain extenders that decrease the terminal PET COOH content by these decomposition reactions. 

Phenyl acetate Phenyl propanoate Phenyl butanoate Diphenyl oxalate Phenyl salicylate (salol)... 

Measured changes in RON, ARON in a 96 RON gasoline produced by addition of 0.025 mol/1 of methyl substituted diphenyl oxalate additives [26]... 

As confirmation of an inert radical production mechanism, iodine compounds are particularly effective because of the production of I atoms. However, there are big deficiencies in our understanding of the details of anti-knock chemistry. This is illustrated by the large differences in antiknock effectiveness shown in MacKinven s measurements between substances with apparently very similar composition [27]. As shown in Table 7.3, some of the methyl substituted diphenyl oxalates are quite good antiknocks, with up to 1.1 times the molar effectiveness of NMA. But another is pro-knock. The mechanism responsible for this structure/property dependence is not known. More recently, high effectiveness has been reported for ashless materials related to dialkyl amino fulvenes [28-31], but no credible mechanisms have been published. No ashless anti-knocks have proved sufficiently cost-effective to be used commercially. 

Luminol and diphenyl oxalate are two compounds very frequently used in a variety of classic applications from non-electric emergency lighting to the hoops, necklaces and light batons sold at fairgrounds. The reactions that causes emission are all oxidations by hydrogen peroxide. 

Figure 11.14 Examples of chemiluminescence reactions. The nature of the reaction products is sometimes not well known. Luminol emits an intense electric blue light while the diphenyl oxalate, depending upon the colouring agent used, leads to the emission of a great variety of colours.

Stoichiometric use of [Pd(CO)X] produced DPC in moderate yield based on palladium (Scheme Phenyl salicylate 17 and o-phenylenecarbonate 18 are typical by-products in DPC synthesis, but formation of diphenyl oxalate has not been reported. 

Potassium 1,2-diseleno-oxalate has been prepared by saponification of diphenyl oxalate by alcoholic KjSe. It is very sensitive to oxygen. The ion was shown by X-ray analysis to have the rrans-planar conformation (116). ... 

The initiating radicals are assumed to be SCN, ONO or N3 free radicals. Tris oxalate-ferrate-amine anion salt complexes have been studied as photoinitiators (A = 436 nm) of acrylamide polymer [48]. In this initiating system it is proposed that the CO2 radical anion found in the primary photolytic process reacts with iodonium salt (usually diphenyl iodonium chloride salt) by an electron transfer mechanism to give photoactive initiating phenyl radicals by the following reaction machanism ... 

Diethyl ketone Diethyl oxalate Diethylene glycol Diphenyl Dipropyl ether Dipropyl oxalate Ethyl acetate Ethyl acrylate Ethyl alcohol, 100%... 

Me Capra in particular proposed n> that the chemiluminescence reactions of a large number of organic compounds had this concerted dioxetane decomposition step as key reaction in the production of electronically excited products, namely acridinium salts 25,26,27) indolylperoxides 28>, activated oxalic esters 29>, diphenyl carbene 30>, tetrakis-dimethylamino-ethylene 31 32>, lucigenin 33>, and substituted imidazoles 23>. 

To a solution of oxalic chloride (5 g) in dichloromethane, a solution of diphenyl amine (5 g) in dichloromethane was added dropwise and refluxed for 30 min. The solution was concentrated (50%) and aluminum trichloride (8 g) added in portions. The mixture was refluxed for 45 min and the solvent evaporated. To this residue hydrochloric acid in ice water (1 M) was added and the red-colored precipitate filtered. The precipitate was dissolved in potassium hydroxide (10% in water), refluxed overnight, and poured into hydrochloric acid in ice water (5 M). The yellow acridine-9-carboxylic acid was filtered, washed with water, and dried. 

Aromatic polycarbonates are currently manufactured either by the interfacial polycondensation of the sodium salt of diphenols such as bisphenol A with phosgene (Reaction 1, Scheme 22) or by transesterification of diphenyl carbonate (DPC) with diphenols in the presence of homogeneous catalysts (Reaction 2, Scheme 22). DPC is made by the oxidative carbonylation of dimethyl carbonate. If DPC can be made from cyclic carbonates by transesterification with solid catalysts, then an environmentally friendlier route to polycarbonates using C02 (instead of COCl2/CO) can be established. Transesterifications are catalyzed by a variety of materials K2C03, KOH, Mg-containing smectites, and oxides supported on silica (250). Recently, Ma et al. (251) reported the transesterification of dimethyl oxalate with phenol catalyzed by Sn-TS-1 samples calcined at various temperatures. The activity was related to the weak Lewis acidity of Sn-TS-1 (251). 

Warbentin (19) has indicated how the radical thermochemistry involved can assist in assigning a mechanism for the thermal decomposition of phenyl oxalate. Exclusive initial fission of either the one C—C or the two C—O bonds would lead, via PhOCO or OCCO intermediates, to high C02 or high CO yields. In experiments lasting about 75 hours at 500°K. in diphenyl ether, comparable amounts of CO (13%) and C02 (9% ) are formed. The following steps, possibly concerted ... 

Diethyl oxalate is also reported to form an oxetane with 1,1-diphenyl-ethene and 2-phenyl propene.102... 

This however is not the whole story, for resinous products, oxalic acid, and ammonia are also formed. If the reaction with caustic alkali is carried out in the presence of thiophenol, some glycerin is formed and the thiophenol is oxidized to diphenyl sulfide. Alkali sulfides, K2S, KHS, and CaS, also yield glycerin. 

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