Phthalic acid anhydride, reaction with

BENZENEDICARBOXYLIC ANHYDRIDE (85-44-9) Combustible solid (flash point 30,5°F/152°C cc). Dust or powder can form explosive mixture with air, with possible spontaneous ignition. Decomposes in water, forming phthalic acid. Violent reaction with aniline, strong oxidizers. barium peroxide, calcium permanganate, 1,2-diaminoethane, 1,3-diphenyltriazene... 

Zinc phthalocyanine (PcZn) is prepared from phthalonitrile in solvents with a boiling point higher than 200 C, e.g. quinoline277,278 or 1-bromonaphthalene,137 or without solvent in a melt of phthalonitrile.83,116 The zinc compound normally used is zinc(ll) acetate or zinc powder. The reaction of zinc(II) acetate with phthalic acid anhydride, urea and ammonium mo-lybdate(VI) is also successful.262 The metal insertion into a metal-free phthalocyanine is carried out in an alcohol (e.g.. butan-l-ol).127,141,290 This reaction can be catalyzed by an alkali metal alkoxide.112,129... 

Phosphorus pentachloride, for conversion of pentaacetylgluconic add to add chloride, 41, 80 for oxidation of cycloheptatriene to tropylium fluoborate, 43, 101 with cyanoacetic acid, 41, 5 Phosphorus tribromide, reaction with 1.5-hexadien-3-ol, 41, 50 Phthalic anhydride, reaction with L-phenylalanine to yield N-phthalyl-L-phenylalanine, 40, 82 Phthalic monoperacid, 42, 77 N-Phthalyl-i.-alanine, 40, 84 N-Phthalyl-/3-alanine, 40, 84 N-Phthalylglycine, 40, 84 N-Phthalyl-l-/5-phenylalanine, 40, 82... 

A racemic alcohol may be converted into a racemic acid by reaction with one molar equivalent of phthalic anhydride the product is a half ester of a dicarboxylic acid (see Section 7.9.1). This can now be subjected to the resolution process for acids and, in due course, the alcohols can be regenerated by hydrolysis of the ester. 

The benzenedisulfonic acids are of little interest, except that benzene-1,3-disulfonic acid is a source of 1,3-dihydroxybenzene (see Chapter 4). The benzene dicarboxylic acids are more important. Benzene-1,2-dicarboxylic acid (phthalic acid, 8) can be converted into phthalic anhydride (9), which is a typical acid anhydride, reacting with amines and alcohols and also taking part in Friedel-Crafts reactions. Phthalimide (10), produced by reaction of the anhydride with ammonia, is weakly acidic and forms a potassium salt with ethanolic potassium hydroxide. 

In our experience pulverization of phthalic anhydride is tedious and we prefer crystallization, which provides material in a form suitable for ready reaction and which eliminates any phthalic acid, usually present in a sample taken from a previously opened bottle. The anhydride is boiled with a liberal quantity of benzene, and the hot solution is filtered from any undissolved phthalic acid and diluted with ligroin. A modification of a published method is as follows. A mixture of 66 g. of the crystallized anhydride, 92 g. of sodium perborate, and 280 ml. of water is stirred at 0° for 2 hrs., shaken with ether, and acidified with 120 ml. of ice-cold 30% sulfuric acid. Extraction is done as described above. 

The last reaction illustrates how useful it can be to convert an acid first into its anhydride and then into its chloride. Most carboxylic anhydrides are relatively stable to inorganic acid chlorides cyclic anhydrides are even formed preferentially if a dicarboxylic acid such as maleic, tartaric, or phthalic acid is treated with an inorganic acid chloride such as SOCl2 under the usual conditions 1092 however, phthalic anhydride is converted by PC15 at higher temperatures into phthaloyl dichloride (A). 

Simple alcohols with only one hydroxy function and one asymmetric carbon atom are classical chiral chemicals. While they are often commercially available, they are relatively expensive. Until recently, they were obtained mainly by resolution of the racemates using a reliable but not very convenient technique. Reaction of the racemic alcohol with phthalic acid anhydride gave the monoester of phthalic acid, which was resolved by salt formation with a chiral base, usually brucine, or occasionally also strychnine or cinchonidine. The methyl carbinols from 2-butanol 1 to 2-tridecanol were first obtained by this method1,2 and this was later extended to 3,3-dimethyl-2-butanol3. When crystallization of the diastereomeric salts was performed in the presence of triethylamine, some other methyl carbinols could also be resolved, such as... 

Phthalyl chloride is formed when phthalic acid is treated with phosphorus pentachloride. It has the structure represented by formula (1) below and melts at 16°. In certain of its reactions it behaves as if it were the derivative of phthalic anhydride indicated by formula (2). The relation between the three compounds is indicated by the following formulas —... 

Starting material for the industrial synthesis is phthalide, which may be obtained by hydrogenation of phthalic anhydride. Reaction with o-cresol leads to the corresponding carboxyUc acid, which is converted via its acid chloride into the acyl cyanide. A Pinner reaction and treatment with methoxyamine finally give kresoxim-methyl. [59]... 

For phthalic acid anhydride (PSA) the (released) heat of reaction is theoretically —7.5 kj per g-PSA, that is, for o-xylene oxidation with 100% selectivity to PSA (see Section 6.13). Industrial plants consume (without feed) 22 kJ per g-PSA, but according to Figure 5.5.4 this value should be around zero. The main reason for this difference is that the selectivity of catalytic o-xylene oxidation to PSA is less than 80%, and unwanted total oxidation to CO2 takes place. 

Catalytic partial oxidation of o-xylene and naphthalene is performed mostly in intensively cooled multi-tubular fixed bed reactors, but systems with a fluidized bed were also developed. Typically, V20s/Ti02 catalysts with K2SO4 or A1 phosphates as promoter are used. In fixed bed reactors, the conversion of both feedstocks per pass is around 90%, and the selectivity is in the range 0.86-0.91 mol PA per mol naphthalene and 0.78 mol per mol o-xylene. (Note that the selectivity would be 100%, if only the reactions according to Eqs. (6.13.1) and (6.13.2), respectively, would take place.) The active compounds are distributed on spheres of porcelain, quartz, or silicium carbide (shell catalyst). The thickness of the shell is only around 0.2 mm, and the diffusion paths for the reactants are short. By this means, the influence of pore diffusion is small, and the unwanted oxidation of phthalic acid anhydride to CO2 is suppressed compared to a catalyst with an even distribution of active compounds where the influence of pore diffusion would be much stronger (see Section 4.5.6.3 Influence of Pore Diffusion on the Selectivity of Reactions in Series ). Thus the intrinsic reaction rates are utilized for the modeling of a technical reactor (next Section 6.13.2). 

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)].

---