Other products from phthalic anhydride

Other uses for phthalic anhydride, but of less importance in terms of quantity, are in the production of pigments, dyes and phthalimide, which is used as a raw material in the production of anthranilic acid, pesticides and pharmaceutical products. 

The reaction of chlorobenzene with phthalic anhydride to yield 2-chloro-anthraquinone, which is used as an intermediate in the production of indanthrone (see Chapter 11.3.2), was of great industrial importance for the early tar-based dyestuffs industry. Reaction of phthalic anhydride with quinaldine yields quino-phthalone, which is the basis of the quinoline yellow dyes. 

Heating PA with phenol in the presence of concentrated sulfuric acid leads to phenolphthalein (see Chapter 7.1.1), which was discovered by Adolf von Baeyer in 1871. 

The phthalocyanines, as copper, cobalt and nickel complexes, discovered in the 1920 s, form a versatile group of pigments they display high color-fastness with blue to green shades, depending on the degree of halogen substitution. Phthalocyanines can be produced by the widely-used synthesis from phthalic anhydride and urea as well as from phthalodinitrile. 

The reaction of urea, CuCl and phthalic anhydride is carried out at ca.200 °C in a process lasting 2 to 3 hours, using ammonium molybdate as a catalyst nitrobenzene, trichlorobenzene or kerosene can be used as solvents. When phthalodinitrile is used, the reaction is carried out without catalyst at ca. 200 °C as a baking process or in solution. When the crude phthalocyanine has been produced, it is conditioned to suitable crystal modifications, e.g. by dissolving in sulfuric acid and subsequent hydrolysis, or treatment with organic solvents. 

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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. 

Extension of the Kunii-Levenspiel bubbling-bed model for first-order reactions to complex systems is of practical significance, since most of the processes conducted in fluidized-bed reactors involve such systems. Thus, the yield or selectivity to a desired product is a primary design issue which should be considered. As described in Chapter 5, reactions may occur in series or parallel, or a combination of both. Specific examples include the production of acrylonitrile from propylene, in which other nitriles may be formed, oxidation of butadiene and butene to produce maleic anhydride and other oxidation products, and the production of phthalic anhydride from naphthalene, in which phthalic anhydride may undergo further oxidation. 

The glyptals made from phthalic anhydride and glycerol were developed as compositions for use in paints and varnishes. If the reaction was carried out too long the product became intractible. But under milder conditions, other products could be obtained which could be used in making soluble products and then they could be set further after forming. It was learned that by modifying the reaction mixture with some monobasic acid to balance the hydroxyls and carboxyls in the reaction mixture, more soluble products could be obtained. Kienle of General Electric, was one of the early developers of these products. Later many other alkyd resins from other polyhydroxyl compounds and poly acids were produced for technical use. 

The alkyl naphthalenes, such as methyl naphthalene, may be oxidized to phthalic anhydride in the same manner as naphthalene, thus making it possible to use cruder grades of naphthalene. Thus, crude naphthalene obtained by centrifuging the oils from the proper cut from the distillation of coal-tar (whizzed naphthalene) consisting principally of naphthalene to the extent of 50 to 80 per cent and usually containing considerable quantities of alkyl naphthalenes and other ring compounds may be treated in a manner similar to that used in the oxidation of pure naphthalene. The reaction products contain phthalic anhydride, benzoic acid, naphthoic acids and anhydrides, etc.81... 

In 1928, at Grangemouth, Scotland, at the works of Messrs. Scottish Dyes Ltd., traces of a dark blue insoluble complex were noticed in the iron vessels used to prepare phthalimide from phthalic anhydride and ammonia (65, 221). This product was subsequently shown to be ferrous phthalo-cyanine. Since then literally thousands of patents and publications concerning the phthalocyanines have appeared. It is probable that the phthalocyanines have been the subject of more physical studies than any other single class of compound, partly as a result of their unique structure and partly because of their high thermal and chemical stability. 

A number of derivatives of fluorescein are useful dyes. Uranin is the disodium salt of fluorescein. ChrysoUn is a salt of benzyl-fluorescein, which is formed from phthalic anhydride and benzyl-resorcinol. It dyes silk and wool a fast yellow, and is used in cotton dyeing. Eosin is the disodium salt of tetrabromo-fluorescein, which is prepared by the action of bromine on fluorescein. Its dilute alkaline solution is rose-colored, and exhibits an intense yellow-green fluorescence. Other dyes related to fluorescein are tetrabromo-dichlorofluorescein and various ethers of fluorescein and its substitution-products. The dyes of this class produce on silk and wool shades from yellow to reddish yellow, cherry-red, and purple. 

Distillation with reaction, where the normal process is coupled with a liquid phase reaction, is also interesting and esterifications of certain alcohols with acids are typical industrial applications. These include, among others the homogeneously catalyzed butyl acetate process and the production of the plasticizer di-octyl-phthalate from phthalic anhydride and 2-ethyl-hexanol. However, the subject which involves both product formation and separation aspects has not usually been treated in the literature relating specifically to "mass transfer with reaction". 

Unmodified rosins combine with fumaric acid and maleic anhydride in accordance with the Diels-Alder reaction to form tribasic adducts. The resulting polybasic acids are often used instead of phthalic anhydride in the production of alkyd resins for low-cost coatings. These rosin-derived, nonphthalate alkyds are used to improve gloss and other properties and are suitable mainly for interior coalings. They do not possess the high degree of outdoor durability characteristic of alkyd resins derived solely from phthalic anhydride. 

You have recendy joined the TBWS Chemical Corporatiom One of TBWS s major businesses has always been production of phthalic anhydride from naphthalene. Phthalic anhydride production is integrated as part of a large chemical plant, in which naphthalene is produced and in which phthalic anhydride is immediately used to make polyester resins. In recent years, there have been some problems. Some end users have complained about the quality of the resins produced and have taken their business to other companies that produce phthalic anhydride from o-xylene. Therefore, our plant, which had been designed to produce 100,000 metric tons/year of phthalic anhydride from naphthalene, was scaled back to about 80,000 metric tons/year several years ago. We are now forced to scale down production once again due to the loss of another large customer. Marketing informs us that we may lose additional customers. 

The first commercial production unit was built by the National Aniline and Chemical Company, part of the Barrett Company, in 1933. However, most of the maleic anhydride used at that time was supphed from phthalic anhydride plants, which produced about 5-10% as a by-product. Demand for maleic anhydride was still low during the 1940s. At that time two typical catalysts were available. One contained 12% vanadium pentoxide/4% molybdenum trioxide supported on a-alumina, while the other contained 10% vanadium pentoxide moderated with less than 1% of lithimn sulfate/sodium sulfate, also supported on a-alumina. The alkali sulfate moderated catalyst was, however, sensitive to sulfur poisons in the benzene feed. 

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. 

The baking process has remained much the same until the present day at a stoichiometric ratio of 1 4, phthalic anhydride or phthalic acid reacts with an ammonia releasing compound. The reaction may also start from other suitable materials, such as phthalic acid derivatives, including phthalic acid esters, phthalic acid diamide, or phthalimide. Appropriate ammonia releasing agents include urea and its derivatives, such as biuret, guanidine, and dicyanodiamide. The fact that a certain amount of urea decomposes to form side products makes it necessary to use excess urea. Approximately 0.2 to 0.5, preferably 0.25 equivalents of copper salt should be added for each mole of phthalic anhydride. 0.1 to 0.4 moles of molybdenum salt per mole of phthalic anhydride is sufficient. The reaction temperature is between 200 and 300°C. 

Considerable research effort has been devoted in recent years to the use of chloral derivatives for the synthesis of linear heterocyclic polymers. Of these, the most common are aromatic polyimides [1-12], Many of these polymers have been synthesised from compounds like 4,4 -diaminobenzophenone, and other diamines, which, as demonstrated in the previous chapter, can be obtained from chloral. Polyimides prepared from these diamines were largely synthesised by the conventional two-step procedure [11, 12] involving mild reaction of the diamines with the bis(phthalic)anhydrides, isolation of poly(o-carboxy)amide (PCA) prepolymers, and then processing into products followed by thermal or chemical imidisation [13—16] (Scheme 3.1). Some properties of polyimides prepared from 4,4 -diaminobenzophenone are provided in Table 3.1. 

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