Phthalic production

Used as fibres, particularly in textiles and film. Many other polyester polymers are of importance, e.g. unsaturated polyester resins from phthalic anhydride, propylene glycol and maleic anhydride used with reinforcement in boats, cars, etc. (alkyd resins). U.S. production 1983 1-7 megatonnes. 

It is extensively used in the preparation of dyestuffs. Combines with diazonium salts to form oxyazo-colouring matters. Gives rise to fluorescein dyes on fusion with phthalic anhydride. Used for production of plasticizers, resins, adhesives. 

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. 

Reactions of the Methyl Groups. These reactions include oxidation, polycondensation, and ammoxidation. PX can be oxidized to both terephthahc acid and dimethyl terephthalate, which ate then condensed with ethylene glycol to form polyesters. Oxidation of OX yields phthaUc anhydride, which is used in the production of esters. These ate used as plasticizers for synthetic polymers. MX is oxidized to isophthaUc acid, which is also converted to esters and eventually used in plasticizers and resins (see Phthalic acids and otherbenzenepolycarboxylic acids). 

Henkel Rearrangement of Benzoic Acid and Phthalic Anhydride. Henkel technology is based on the conversion of benzenecarboxyhc acids to their potassium salts. The salts are rearranged in the presence of carbon dioxide and a catalyst such as cadmium or zinc oxide to form dipotassium terephthalate, which is converted to terephthahc acid (59—61). Henkel technology is obsolete and is no longer practiced, but it was once commercialized by Teijin Hercules Chemical Co. and Kawasaki Kasei Chemicals Ltd. Both processes foUowed a route starting with oxidation of napthalene to phthahc anhydride. In the Teijin process, the phthaHc anhydride was converted sequentially to monopotassium and then dipotassium o-phthalate by aqueous recycle of monopotassium and dipotassium terephthalate (62). The dipotassium o-phthalate was recovered and isomerized in carbon dioxide at a pressure of 1000—5000 kPa ( 10 50 atm) and at 350—450°C. The product dipotassium terephthalate was dissolved in water and recycled as noted above. Production of monopotassium o-phthalate released terephthahc acid, which was filtered, dried, and stored (63,64). 

Naphthalene. Until the 1960s, the principal outlet for naphthalene was the production of phthaHc anhydride however, more recently, o-xylene has replaced naphthalene as the preferred feedstock (see Phthalic acids). Nevertheless, of the 201,000 t produced in 1994 in Japan, 73.2% was used for phthaHc anhydride production. The rest was consumed in dye stuffs manufacture and a wide variety of other uses. Naphthalene is also used to produce phthaHc anhydride in the United Kingdom, Belgium, and the C2ech RepubHc, and can be used by Koppers in the United States in time of o-xylene shortages. In Europe, the traditional uses for naphthalene have been for the manufacture of P-naphthol and for dye stuff intermediates (see Dyes and dye... 

The fully side-chaia chloriaated products, 1,3-his(trichioromethy1)henzene [881-99-1] and 1,4-his(trichioromethy1)henzene [68-36-0] are manufactured by exhaustive chlorination of meta and para xylenes. For the meta compounds, ring chlorination cannot be completely eliminated ia the early stages of the reactioa. The xyleae hexachlorides are iatermediates ia the manufacture of the xylene hexafluorides and of iso- and terephthaloyl chloride [100-20-9] (see Phthalic acids). 

Cobalt in Catalysis. Over 40% of the cobalt in nonmetaUic appHcations is used in catalysis. About 80% of those catalysts are employed in three areas (/) hydrotreating/desulfurization in combination with molybdenum for the oil and gas industry (see Sulfurremoval and recovery) (2) homogeneous catalysts used in the production of terphthaUc acid or dimethylterphthalate (see Phthalic acid and otherbenzene polycarboxylic acids) and (i) the high pressure oxo process for the production of aldehydes (qv) and alcohols (see Alcohols, higher aliphatic Alcohols, polyhydric). There are also several smaller scale uses of cobalt as oxidation and polymerization catalysts (44—46). 

Phthalic anhydride and diethyl phthalate are easily converted with hydrazine into 4-hydroxyphthalazin-l(2/f)-one. Its substituted derivatives have been prepared using substituted hydrazines, substituted phthalic anhydrides, or diesters or disodium salts of substituted phthalic acids (Scheme 81). However, condensation of phenylhydrazine with phthalic anhydride gives only a small amount of the corresponding phthalazine, the main product being 2-anilinophthalimide. This can be rearranged in the presence of base into the phthalazine derivative. For the preparation of 2,3-disubstituted derivatives, 1,2-disub-stituted hydrazines are reacted with the appropriate phthalic anhydrides or phthaloyl chlorides. Derivatives of 4-amino- or 4-hydrazino-phthalazin-l(2iT)-one have been prepared either from the corresponding monothiophthalimide and 3-aminoisoindolin-3-one (1S4) or from ethyl 2-cyanobenzoate (155) and hydrazine hydrate (Scheme 82). Similarly,... 

Aminothiophenes and 3-aminobenzo[Z)]thiophene undergo thermal [2 + 2] cycloaddi-tion reactions with activated alkynes. The reactions are solvent dependent thus in non-polar solvents at -30 °C, 3-pyrrolidinothiophene adds to DMAD to give a [2 + 2] cycloadduct which is ultimately converted into a phthalic ester. In methanol, however, a tricyclic product is formed (Scheme 54) (81JOC424. ... 

D. ci - -Thiabicyclo[4 .. Q]nonan S,S-Dioxide [Benzo[c]thiophene 2,2-dioxide, cis-octahydro-]. A solution of the sulfide (43.0 g., 0.303 mole) in 11. of ether is cooled to 0° and treated dropwise while magnetically stirred with 1.01. of 0.65iV ethereal monoperphthalic acid (0.65 mole). The mixture is kept overnight at 0°, after which time the precipitated phthalic acid is separated by filtration and the filtrate concentrated with a rotary evaporator. Bulb-to-bulb distillation of the residual oil at 0.05-0.1 mm. affords the sulfone as a eolorless liquid (48.5-50 g., 92-95%) (Note 11). This product is crystallized from ether-hexane to give a colorless solid, m.p. 39-41° (Note 12). 

The checkers performed this step on a smaller scale (ca. f) and noted (proton magnetic resonance spectrum) occasional contamination (up to 10%) by phthalic anhydride. This impurity causes no subsequent difiSculties. Washing of the crude reaction mixture with cold aqueous sodium hydrogen carbonate resulted in serious product loss because of its appreciable solubility in this medium and therefore should be avoided. 

Until the mid-1950s the main raw material source for the European plastics industry was coal. On destructive distillation coal yields four products coal tar, coke, coal gas and ammonia. Coal tar was an important source of aromatic chemicals such as benzene, toluene, phenol, naphthalene and related products. From these materials other chemicals such as adipic acid, hexamethylenedia-mine, caprolactam and phthalic anhydride could be produced, leading to such important plastics as the phenolic resins, polystyrene and the nylons. 

This will lead initially to branched chain structures such as indicated schematically in Figure 2.10, G indicating a glycerol residue and P a phthalic acid residue. In due course these branched molecules will join up, leading to a cross-linked three-dimensional product. 

Fumaric acid may be prepared by heating maleic acid, with or without catalysts. It is also obtained as by-product in the manufacture of phthalic anhydride from naphthalene. The acid is a solid melting at 284°C. Fumaric acid is sometimes preferred to maleic anhydride as it is less corrosive, it tends to give lighter coloured products and the resins have slightly greater heat resistance. 

The phthalic acid and benzoic acid are reacted to form a reaction intermediate. The reaction intermediate is dissolved in sulfuric acid, which precipitates terephthalic acid (TPA). Fifty percent of the TPA is sold as a product and 50 percent is further processed at your facility into polyester fiber. The TPA Is treated with ethylene glycol to form an intermediate product, which is condensed to polyester. 

Confirmation of this constitution was provided by Spath and Becke, > who identified 5-methoxy-3 4-methylenedioxy-o-phthalic acid as an oxidation product of anhalonine. The synthetic df-anhalonine was resolved by crystallisation of the f-tartrate from methyl alcohol, into f-anhalonine, m.p. 85-6°, — 56-3° (CHCI3) and its optical antipode,... 

An interesting extrapolation of this synthesis deals with the preparation of the bispyridinium salt 62 from 1,2-phthalic dicarboxaldehyde and its subsequent reaction with primary amines (92BSB509).Tlie expected diimines 63 readily cyclize so that 2-aryl-l-arylimino-2,3-dihydro-l//-isoindoles 64 can be isolated in excellent yields (90-95%). Contrary to the reactions performed by employing the dialdehyde and amines directly, the syntheses involving the azinium salts do not produce those typical dark-colored complex mixtures of products (77JOC4217 85JHC449) (Scheme 20). 

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