Phthalic acid, heat reaction

Saturated polyester resins (alkyd or glyptal resins) are made from polyalcohols with a functionality of 3 or more (e.g. glycerol, pentaerythritol (C(CH20H)4), sorbitol) with dicarboxylic acids (e.g. succinic, maleic, phthalic acids). The reaction is allowed to proceed to a viscous oil which can be applied as a coating, adhesive, etc., and then heated or cured to a thermoset. 

Phthalylacetic acid. Heat a mixture of 30 g. of phthalic anhydride, 40 ml. of acetic anhydride and 5 g. of potassium acetate under reflux in an oil bath at 155-165° for 15 minutes. Pour the reaction mixture into ice-cold water, collect the yellow precipitate by suction filtration, wash it three times with 25 ml. of water and once with 10 ml. of 50 per cent, ethanol. Dry the. product at 100° the yield of crude plithalylaeetie acid is 20 g. Recrystallise from hot methanol yellow needles, m.p. 245-246°, are obtained. 

Phthalocyanines have been synthesized with nearly all metals of the periodic table.77 Normally they are formed in a single-step reaction from available derivatives of phthalic acid, in particular phthalic acid (see Section 2.1.1.1.), phthalic anhydride (see Section 2.1.1.2.), phthalimide (see Section 2.1.1.3.), 2-cyanobenzamide (see Section 2.1.1.4.), phthalonitrile (see Section 2.1.1.5.), isoindolinediimine (see Section 2.1.1.6.), or 1,2-dibromobenzene (see Section 2.1.1.7.), usually in a high-boiling solvent or by heating the neat components.1 4... 

The solution is allowed to cool, and the di- -butylamine hydrobromide, which separates in the course of the reaction, is removed by means of a suction filter (Note 2). The filtrate is transferred to a 500-ml. distilling flask, and the xylene is removed by distillation. The crude y-di-w-butylaminopropylphthalimide, a brown oil, is transferred to a 500-ml. round-bottomed flask with a ground-glass joint and treated with 20 ml. of water and 120 ml. of 12 N hydrochloric acid. The flask is fitted with a reflux condenser, and the solution is heated for 6 hours in an oil bath maintained at 140-150°. After the solution has cooled to room temperature, the precipitated phthalic acid is removed by filtration and washed with four 25-ml. portions of cold water. The combined filtrates are transferred to a 600-ml. beaker and heated on a steam bath to evaporate the water and hydrochloric acid. 

Reaction CIX.. Action of Heat on certain Dibasic Acids. (B., 10, 326.) —When acids such as phthalic acid or succinic acid, which contain two carboxyl groups attached to adjacent carbons, are heated, they readily lose water and pass into the acid anhydride. 

In a typical run, the nitrile 1 (30 mmol) and phthalic acid 2 (36 mmol) were introduced into the reactor, and heated under stirring. In the kinetic studies, time zero is taken at complete dissolution of the phthalic acid. At the desired reaction time, the reactor was rapidly cooled in a water-ice mixture and then chloroform (30 mL) was added. The mixture was stirred for 5 min and then the solid was filtered off. The chloroform solution contains the unchanged nitrile 1, the amide and the carboxylic acid 3. The residual solid contains unchanged phthalic acid 2, phthalimide 4, and as the major component, phthalic anhydride 5. The volume of the chloroform solution was adjusted to 50 mL and naphthalene was added as an internal standard. The resulting solution was analyzed by GLC. 

Combustible when exposed to heat or flame can react with oxidizing materials. Violent reaction with CI2. Incompatible with chlorine. To fight fire, use CO2, dry chemical. When heated to decomposition it emits acrid smoke and fumes. See also ESTERS, PHTHALIC ACID, and n-BUTYL ALCOHOL. 

Equations (II) to (IX) illustrate basic methods of preparation, but many variations are used, particularly in industry, to obtain an economic yield. Phthalic acid, phthalamide, phthalimide, and phthalic anhydride, together with urea, are often used instead of phthalonitrile, and catalysts such as ammonium molybdate or zirconium tetrachloride may be employed (249, 251, 269). The reaction between phthalonitrile and metals (finely divided or acid-etched) is usually very vigorous at 250°-300°C, sufficient heat being generated to maintain the reaction temperature. This is an illustration of the ease with which the phthalocyanine skeleton is formed. Even more surprising are the observations that palladium black (118) and gold (189) will dissolve in molten phthalonitrile. Reaction (III) between phthalonitrile and a finely divided metal, metal hydride, oxide, or chloride is perhaps the most generally employed. For the unstable phthalocyanine complexes such as that of silver (11), the double decomposition reaction... 

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