Phthalides phthalic acid anhydride

A) Preparation of Thenylidene-(2)-Phthalide 24.2 g of thienyl-(2)-acetic acid, 52.0 g of phthalic acid anhydride, 4.0 g of anhydrous sodium acetate and 125 ml of 1-methylpyr-rolidone-(2) are heated while stirring in an open flask for 3 hours to 205° to 208°C, while nitrogen is passed through. It is then cooled and the viscous reaction mixture poured into... 

Oxidation, also partial, of methyl to carboxyl groups—Phthalic acid anhydrides from phthalides s. 16, 228 benzoic acid s. G. Messina, Hydrocarbon Process Petrol. Refiner A3 (11), 191 (1964) C. A. 62, 2733g... 

More than 10 years after the establishment of the acetalization process, electrochemists at BASF have searched for a compatible reductive process that can be run instead of the hydrogen evolution. What they have found is the reduction of phthalic acid dimethylester to phthalide [8] (Fig. 2). Phthalide is a compound that was up till then generated by classical catalytic hydrogenation from phthalic acid anhydride [7]. Part of the process development has been to fit the paired electrosynthesis in the same capillary gap cell like the acetalization of the toluene derivatives. 

Scheme6.13.1 Simplified reaction scheme of catalytic o-xylene oxidation to phthalic acid anhydride. [A more complex network with o-tolualdehyde and phthalide anhydride as intermediates is proposed by Calderbank, Chandrasekharan, and Fumagalli (1977), Anastasov (2002,2003) and Fiebig and Kuchling (2009)].

Carboxyphenyl-(2-methyl-3-indoleninjdidene)methanol (303) was said to be formed by the action of phthalic anhydride on 2-methyl-indole magnesium bromide. Skatole magnesium bromide, on the other hand, apparently gave 2-carboxyphenyl-(3-methyl-2-indole-ninylidene)methanol (304) and 3-hydroxy-3-(3-methyl-l-indolyl)-phthalide (305) on treatment with 1 mole of phthalic anhydride. The derivative 305 was easily hydrolyzed in alkali, giving skatole and phthalic acid, and was thus formulated as a 1-skatolyl derivative. ... 

Acid Curing. Urea-formaldehyde resins and resol-phenol-formaldehyde resins can be acid-cured by wastes from the production of maleic anhydride [1902]. The waste from the production of maleic anhydride contains up to 50% maleic anhydride, in addition to phthalic anhydride, citraconic anhydride, benzoic acid, o-tolulic acid, and phthalide. The plugging solution is prepared by mixing a urea-formaldehyde resin with a phenol-formaldehyde resin, adding the waste from production of maleic anhydride, and mixing thoroughly. 

The first examples of a homogeneous reduction of this type were reported in 1971. Cobalt carbonyl was found to reduce anhydrides such as acetic anhydride, succinic anhydride and propionic anhydride to mixtures of aldehydes and acids. However, scant experimental details were recorded [94]. In 1975, Lyons reported that [Ru(PPh3)3Cl2] catalyzes the reduction of succinic and phthalic anhydrides to the lactones y-bulyrolaclone and phthalide, respectively [95], The proposed reaction sequence for phthalic anhydride is shown in Scheme 15.15. Conversion of phthalic anhydride was complete in 21 h at 90 °C, but yielded an equal mixture of the lactone, phthalide (TON = 100 TOF 5) and o-phthalic acid, which is presumably formed by hydrolysis of the anhydride by water during lactoniza-tion. Neither acid or lactone were further hydrogenated to any extent using this catalyst system, under these conditions. 

Bemardine and Ramacci (in Wainwright and Foster, 1979) studied the oxidation of o-Xylene in the temperature range 380-520°C and were able to identify more than 20 reaction products. They postulated a complex reaction network in which phthalic anhydride is formed via intermediates such as omethylbenzyl alcohol, o-tolualdehyde, o-toluic acid and phthalide. Their conclusion that phthalic anhydride is formed via a series path was based on the fact that each of the... 

Evidence for the formation of maleic anhydride only from the C-atoms of the aromatic ring has been obtained by Blanchard and Vanhove, who found no incorporation of radioactivity in the maleic anhydride formed from the oxidation of o-xy ene (methyl- C) or phthalic anhydride (- CO-) over V2O5 at 420-470 °C. A subsequent investigation by these authors was undertaken to elucidate the reaction pathways involved in the formation of the intermediates o-tolualdehyde, o-toluic acid and phthalide. A competitive oxidation of inactive o-methylbenzyl alcohol and o-xylene (methyl-... 

According to this new reaction network, the starting material is converted to the wanted product PA by three parallel routes via phthalic aldehyde and phthalic acid (reactions 8,9,10), via tolylic acid and phthalide (reactions 5,6,7) and via phthalide (reactions 4 and 7). Phthalic anhydride when formed is very stable but it is converted in part via bencoic acid (reaction 26) over a rather complex reaction scheme to maleic anhydride (MA). Maleic anhydride is formed directly from o-xylene via tolylic aldehyde (reaction 1) and toluene (reaction 11) by two routes and via dimethylben-zochinone (DMBQ) (reaction 15). Toluene and DMBQ are converted over a series of reaction steps to acetic acid. The main by-products, CO and CO2, are predominantly formed directly from o-xylene according to this mechanistic study. 

Condensation of an appropriately substituted phenylacetic acid with phthalic anhydride in the presence of sodium acetate leads to aldol-like reaction of the methylene group on the acid with the carbonyl on the anhydride. Dehydration followed by decarboxylation of the intermediate affords the methylenephthal-ides (12). Treatment of the phthalides with base affords directly the indandiones, probably via an intermediate formally derived from the keto-acid anion (13). The first agent of this class to be introduced was phenindandione (14) this was followed by anisindandione (1S) and chlorindandione (16). ... 

Phthalic anhydride condenses with the aniline derivative in the presence of zinc or aluminum chlorides to yield the intermediate benzoyl-benzoic acid, which subsequently reacts with l,3-bis-V,V-dimethylaniline in acetic anhydride to yield the phthalide. The above compound gives a violet-gray image when applied to a clay developer. Clearly this synthesis is also very flexible and variations in shades of color formers have been obtained by varying the aniline components and also by using phthalic anhydrides substituted, for example, by nitro groups or chlorine atoms. Such products have excellent properties as color formers and have been used commercially. Furthermore, this synthetic route is of great importance for the preparation of heterocyclic substituted phthalides, as will be seen later. 

Phthalic anhydride, see Benzo[a]anthracene, Bis(2-ethylhexyl) phthalate Carbaryl, Dichlone. Diethyl phthalate, Naphthalene Phthalide, see Naphthalene Phthalimide, see Phorate Picolinamide, see Dignat o-Picolinic acid, see Dignat Picric acid, see Parathion Pinacol, see Acetone Pinonaldehyde, see g-Pinene Polychlorinated dibenzofurans, see PCB-1242,... 

Hydrogenation of phthalic anhydride over copper chromite afforded 82.5% yield of the lactone, phthalide, and 9.8% of o-toluic acid resulting from hydrogenolysis of a carbon-oxygen bond [1015]. Homogeneous hydrogenation of a,a-dimethylsuccinic anhydride over tris(triphenylphos-phine)rhodium chloride gave 65% of a,a-dimethyl- and 7% of )S,)S-dimethyl-butyrolactone [1016]. 

Indicator dyes for pH having the phthalide structure fall into two types, the phthaleins, shown in the lactone form of general structure (1.66) and the sulfoph-thaleins (1.67). The synthetic pathways to these products are very similar. The phthaleins (1.66) are made by reacting phenol with phthalic anhydride in the presence of Lewis acid catalyst, e.g. ZnCl, whilst (1.67) are obtained by using 2-sul-fobenzoic anhydride (Figure 1.20). 

The gas-phase selective oxidation of o-xylene to phthalic anhydride is performed industrially over vanadia-titania-based catalysts ("7-5). The process operates in the temperature range 620-670 K with 60-70 g/Nm of xylene in air and 0.15 to 0.6 sec. contact times. It allows near 80 % yield in phthalic anhydride. The main by-products are maleic anhydride, that is recovered with yields near 4 %, and carbon oxides. Minor by-products are o-tolualdehyde, o-toluic acid, phthalide, benzoic acid, toluene, benzene, citraconic anhydride. The kinetics and the mechanism of this reaction have been theobjectof a number of studies ( 2-7). Reaction schemes have been proposed for the selective pathways, but much less is known about by-product formation. 

Phthalic anhydride, 681, 753, 984, 985 purification of, 507 Phthalide, 753, 772 Phthalimide, 753, 754, 771 Phthalimides, N-substituted, 423 Phthalonitrile, 983 Phthalylacetic acid, 995 Physical constants, determination of, 1028-1037... 

Kinetic and mechanistic investigations on the o-xylene oxidation over V205—Ti02 catalysts were carried out by Vanhove and Blanchard [335, 336] using a flow reactor at 450°C. Possible intermediates like o-methyl-benzyl alcohol, o-xylene-a,a -diol, toluic acid and phthalaldehyde were studied by comparing their oxidation product distribution with that of toluene. Moreover, a competitive oxidation of o-methylbenzyl alcohol and l4C-labelled o-xylene was carried out. The compounds investigated are all very rapidly oxidized, compared with o-xylene, and essentially yield the same products. It is concluded, therefore, that these compounds, or their adsorbed forms may very well be intermediates in the oxidation of o-xylene to phthalic anhydride. The ratio in which the partial oxidation products are formed appears to depend on the nature of the oxidized compounds, i.e. o-methylbenzyl alcohol yields relatively more phthalide, whereas o-xylene-diol produces detectable amounts of phthalan. This... 

McAlees et al. studied the hydrogenation of various phthalic anhydrides over 10% Pd-C in ethyl acetate.62 Hydrogenation of phthalic anhydride gave o-toluic acid in high yield. Either 3- or 4-substituted phthalic anhydrides may give phthalides and/or 2-(hydroxymethyl)benzoic acids in addition to o-toluic acids. In the case of 4-methoxyphthalic anhydride, the product mixture contained 35% of 2-(hydroxymethyl)-... 

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