Phthalic special

The basic patent (US Patent 3256219) indicates that the system is viable with conventional resins although special grades have been developed that are said to be particularly suitable. One example in the patent recommends the use of a polyester prepared using a maleic acid, phthalic acid and propylene glycol ratio of 2 1 33 and with an acid value of 40. To 500g of such a resin are added 10g of benzoyl peroxide and 167 g of styrene. Water 600 g is then stirred in at 5-10°C until a white creamy water-in-oil emulsion is obtained. A solution of 0.8 g of dimethyl-p-toluidine in lOOg of styrene is stirred into the emulsion and the resin is cast between plates and cured at 50°C. 

Section 20.5 Acid anhydrides may be prepared from acyl chlorides in the laboratory, but the most commonly encountered ones (acetic anhydride, phthalic anhydride, and maleic anhydride) are industrial chemicals prepared by specialized methods. 

However, the formation of these products does not appear to play a critical role in the decision as to whether the 425 nm and 480 nm maxima are due to different states of the same molecule or to different compounds. It was reported that special care was taken to ensure the purity of luminol and of 3-aminophthalate 109>. In commercially available 3-amino-phthalic acid a yellowish impurity exhibiting brilliant green fluorescence was detected 109> this substance also formed in neutral solutions of pure 3-amino phthalic acid and crystallized from these solutions in yellow crystals. The structure of this substance was determined to be 53 its absorption spectrum has a maximum at 388 nm the fluorescence maximum is at 475 nm, with a fluorescence quantum yield of about 0.75 in DMF i 9). 

Oleochemical based dicarboxylic acids - azelaic, sebacic, and dimer acid (Figs. 4.5 and 4.6) - amount to ca. 100000 tonnes year-1 as components for polymers. This is about 0.5% of the total dicarboxylic acid market for this application, where phthalic and terephthalic acids represent 87%. The chemical nature of these oleochemical derived dicarboxylic acids can alter or modify condensation polymers, and, used as a co-monomer, will remain a special niche market area. Some of these special properties are elasticity, flexibility, high impact strength, hydrolytic... 

During all of these isolation procedures, special care should be taken to avoid contamination of the samples by plasticizing agents (for example, phthalic esters) which may be derived from the ion-exchange resins or plastic vessels, and which may disturb the following analytical procedures. Thus, use of plastic materials should be largely avoided, and the sialic acids should be processed and stored in glass vessels. 

Di(2-ethylhexyl) phthalate is available in a variety of technical grades (including a special grade for capacitor applications and a low residuals grade). Typical specifications are minimal ester content, 99.0-99.6% maximal moisture content, 0.1% and acidity (as acetic acid or phthalic acid), 0.007-0.01% (Aristech Chemical Corp., 1992 WHO, 1992). 

Aromatic hydrocarbons which have methyl side chains mainly behave like toluene and form aldehydes, while combustion is stimulated and selective oxidation of the nucleus is repressed. The oxidation of methyl-naphthalene, for example, exhibits a low selectivity with respect to phtha-lic anhydride formation, combustion and maleic acid formation being the dominating reactions. Durene is a special case because it resembles o-xy-lene. The oxidation of durene over a V—W—O catalyst at 420° C is reported to produce pyromellitic dianhydride, phthalic and maleic anhydride, although combustion dominates (Geiman et al. [122]). 1,2,4-Trimethyl-benzene yields dimethylbenzene and trimellitic acid if oxidized on a Sn— V—O catalyst. Kinetic data have been measured by Balsubramanian and Viswanath [37]. 

Rubbers. Plasticizers have been used in mbber processing and formulations for many years (8), although phthalic and adipic esters have found litde use since cheaper alternatives, eg, heavy petroleum oils, coal tars, and other predominantly hydrocarbon products, are available for many types of mbber. Esters, eg, DOA, DOP, and DOS, can be used with latex mbber to produce large reductions in T. It has been noted (9) that the more polar elastomers such as nitrile mbber and chloroprene are insufficiently compatible with hydrocarbons and require a more specialized type of plasticizer, eg, a phthalate or adipate ester. Approximately 50% of nitrile mbber used in Western Europe is plasticized at 10—15 phr (a total of 5000—6000 t/yr), and 25% of chloroprene at ca 10 phr (ca 2000 t/yr) is plasticized. Usage in other elastomers is very low although may increase due to toxicological concerns over polynuclear aromatic compounds (9). 

History. Braun and Tschemak [23] obtained phthalocyanine for the first time in 1907 as a byproduct of the preparation of o-cyanobenzamide from phthalimide and acetic anhydride. However, this discovery was of no special interest at the time. In 1927, de Diesbach and von der Weid prepared CuPc in 23 % yield by treating o-dibromobenzene with copper cyanide in pyridine [24], Instead of the colorless dinitriles, they obtained deep blue CuPc and observed the exceptional stability of their product to sulfuric acid, alkalis, and heat. The third observation of a phthalocyanine was made at Scottish Dyes, in 1929 [25], During the preparation of phthalimide from phthalic anhydride and ammonia in an enamel vessel, a greenish blue impurity appeared. Dunsworth and Drescher carried out a preliminary examination of the compound, which was analyzed as an iron complex. It was formed in a chipped region of the enamel with iron from the vessel. Further experiments yielded FePc, CuPc, and NiPc. It was soon realized that these products could be used as pigments or textile colorants. Linstead et al. at the University of London discovered the structure of phthalocyanines and developed improved synthetic methods for several metal phthalocyanines from 1929 to 1934 [1-11]. The important CuPc could not be protected by a patent, because it had been described earlier in the literature [23], Based on Linstead s work the structure of phthalocyanines was confirmed by several physicochemical measurements [26-32], Methods such as X-ray diffraction or electron microscopy verified the planarity of this macrocyclic system. Properties such as polymorphism, absorption spectra, magnetic and catalytic characteristics, oxidation and reduc-... 

The catalytic oxidation of naphthalene can easily be carried out in the laboratory, although the amount of phthalic anhydride which can be prepared in one operation is insignificant. It is of great importance that the correct temperature be maintained and that a suitable catalyst be used. Special attention must be given to the apparatus if the preparation in the laboratory is to succeed. Furthermore, it is highly desirable to use a Cottrel precipitator to collect the reaction product completely. This apparatus will collect even the fine particles, which otherwise would be lost. 

Addition Products.—The halogen addition products of naphthalene ,re more easily formed than are the substitution products. The tetra-chlor compound is of special interest and has been referred to. We have stated that naphthalene is oxidized to or//fo-phthalic acid. This oxidation was originally carried out not with naphthalene itself but with naphthalene tetra-chloride, CioHgCU. When naphthalene is treated with chlorine (potassium chlorate, KCIO3 and hydrochloric acid HCl), addition takes place and the tetra-chlor addition product is formed. By the further action of the chlorine, as an oxidizing agent, the tetra-chloride is converted into ortho-phthalic acid. 

The impurities in phthalic anhydride obtained in the vapor phase oxidation process may he caused to condense or polymerize by heating either with or without the addition of special agents. The vapor pressure of these materials is so lowered by this treatment that subsequent sublimation of tlu- mass results in pure product, the condensed materials remaining in the retort. 

Metal oxide catalysts are extensively employed in the chemical, petroleum and pollution control industries as oxidation catalysts (e.g., oxidation of methanol to formaldehyde, oxidation of o-xylene to phthalic anhydride, ammoxidation of propylene/propane to acrylonitrile, selective oxidation of HjS to elemental sulfur (SuperClaus) or SO2/SO3, selective catalytic reduction (SCR) of NO, with NHj, catalytic combustion of VOCs, etc.)- A special class of metal oxide catalysts consists of supported metal oxide catalysts, where an active phase (e.g., vanadium oxide) is deposited on a high surface area oxide support (e.g., alumina, titania, ziiconia, niobia, ceria, etc.). Supported metal oxide catalysts provide several advantages over bulk mixed metal oxide catalysts for fundamental studies since (1) the number of surface active sites can be controlled because the active metal oxide is 100% dispersed on the oxide support below monolayer coverage,... 

Supported aqueous-phase catalysts (SAPC) can be seen as a special case of adsorption, whereby a water-soluble catalyst dissolved in a very polar solvent is adsorbed on a hydrophilic support forming a water film on the inner surface of the support [30,31]. In the case of supported liquid-phase catalysis (SLPC),the water film on the inner surface is replaced by a solvent of low vapor pressure (e.g.,phthalic acid esters) [2]. The reaction itself takes place in the supported hq-uid or at the interface of the supported liquid film, or in the gas phase or organic phase when dealing with SLPC or SAPC, respectively. The use of SLPC catalysts is generally restricted to the synthesis of low-boiling compounds. 

In industrial operation it is necessary, for economic reasons, to recover as much as possible the heat produced by exothermic reactions. One obvious way of doing this, mentioned earlier in Section 11.3, is to preheat the feed by means of the reacting fluid and/or the effluent. When the heat of reaction is sufficient to raise the temperature of the feed to such a value that the desired conversion is realized in the reactor without further addition of heat, the operation is called auto-thermic. Some of the most important industrial reactions like ammonia and methanol synthesis, SO2 oxidation, and phthalic anhydride synthesis, the water gas shift reaction can be carried out in an autothermic way. Coupling the reactor with a heat exchanger for the feed and the reacting fluid or the effluent leads to some special features that require detailed discussion. 

In practice, esters from adipic, sebacic, and phthalic acid are frequently used as polyester plasticizers. The value of n may vary from 3 to 40 for adipates and from 3 to 35 for sebacates. Polyester plasticizers are seldom used alone. They are used in combination with monomeric plasticizers to reduce the volatility of the mixed solvents. They offer a higher resistance to plasticizer migration and to extract by kerosene, oils, water, and surfactants. Polyester plasticizers are used specially in PVC-based blends and in nitrocellulose varnishes. 

UP resins are soluble linear polycondensation products made from polyvalent -usually unsaturated - acids (e.g. maleic or fumaric acids) and bivalent alcohols (e.g. ethylene glycol and/or 1,2-propylene glycol). For special applications, it is common to substitute some of the a, -unsaturated dicarboxylic acids with phthalic acid and/or adipic acid. Seminal work on unsaturated polycondensation products made from maleic acid, maleic acid anhydride and glycols and on their copolymerisation with styrene is listed in [2.100],... 

After acyl halides, acid anhydrides are the most reactive carboxylic acid derivatives. Although anhydrides can be prepared by reaction of carboxylic acids with acyl chlorides as was shown in Table 19.1, the three most commonly used anhydrides are industrial chemicals and are prepared by specialized methods. Phthalic anhydride and maleic anhydride, for example, are prepared from naphthalene and butane, respectively. 

In this process polyol, dibasic acid and fatty acids are made to react simultaneously at a temperature of 220-260°C until the desired polyester is obtained. In this process, fatty acids compete with the phthalic anhydride and the phthalate half ester for the available hydroxyl groups. In a special modification of the fatty acid process developed by Kraft, the dibasic acid... 

The saturated dicarboxylic acids act as modifiers. While aliphatic dicarboxylic acids can be used, the most common one is ortho phthalic acid (added to the reaction mixture as an anhydride). The acid improves compatibility with styrene that is polymerized in the presence of the polyester to form hard, rigid, cross-linked materials. Other modifiers are used to obtain special properties. When a flexible product is needed, adipic or sebacic acids may be used instead. For better heat resistance, endo-methylene tetrahydrophthalic anhydride (nadic anhydride) may be utilized. Flame retardency is achieved by using chlorinated dicarboxylic acids, like tetrachlorophthalic. 

Any catalyst which becomes entrained in the reaction gases is separated by special filters and returned to the reactor. Up to 60% of the phthalic anhydride can be separated from the reaction product in liquid form by cooling. The remainder is condensed as solid. The uncondensable portions of the reaction product are partially removed by washing the tail gases are incinerated. 

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