Phthalic acid, esterification

Photo-oxidation reactions, 32 118 Photoreduction, metal oxides, 31 123 Phthalic acid, esterification, 17 340 Phthalocyanines EDA complexes of, 20 328-330 catalytic activity for hydrogen exchange reaction, 20 329,330 electronic configuration of, 20 330 organometallic complexes, 30 276-277 Phyllosilicates, see Layer lattice silicates, catalysts... 

Raw Materials. Eor the first decade of PET manufacture, only DMT could be made sufficiently pure to produce high molecular weight PET. DMT is made by the catalytic air oxidation of -xylene to cmde TA, esterification with methanol, and purification by crystallization and distillation. After about 1965, processes to purify cmde TA by hydrogenation and crystallization became commercial (52) (see Phthalic ACID AND OTHER... 

Other large-volume esters are vinyl acetate [108-05-4] (VAM, 1.15 x 10 t/yr), methyl methacrylate [80-62-6] (MMA, 0.54 x 10 t/yr), and dioctyl phthalate [117-81-7] (DOP, 0.14 x 10 t/yr). VAM (see Vinyl polymers) is produced for the most part by the vapor-phase oxidative acetoxylation of ethylene. MMA (see Methacrylic polymers) and DOP (see Phthalic acids) are produced by direct esterification techniques involving methacryHc acid and phthaHc anhydride, respectively. 

Hie most representative member of this class of polyesters is the low-molar-mass (M 1000-3000) hydroxy-terminated aliphatic poly(2,2/-oxydiethylene adipate) obtained by esterification between adipic acid and diethylene glycol. This oligomer is used as a macromonomer in the synthesis of polyurethane elastomers and flexible foams by reaction with diisocyanates (see Chapter 5). Hydroxy-terminated poly(f -caprolactonc) and copolyesters of various diols or polyols and diacids, such as o-phthalic acid or hydroxy acids, broaden the range of properties and applications of polyester polyols. 

Figure 27 shows that the release rate of CBP from the polymer decreased with increasing injection-molding temperatures. Samples with decreased levels of phthalic anhydride and increased levels of the phthalate half ester erode at slower rates presumably because the phthalic acid (pKai = 2.9 and pKa2 = 5.5) is a stronger acid than its alkyl half ester (estimated pKa = 3.6) and because the concentration of acidic groups is reduced by the esterification reaction. 

During the appropriate tests phthalic anhydride was smoothly esterified with 2-ethylhexanol in the mole ratio 1 4. The reaction temperature rose to 200°C. after about 15 minutes, then rose slowly up to 210°C. till the end of the esterification. Table I shows the esterification time in hours after 99.9% conversion, while continuously removing the reaction water, according to the acid number relative to monooctyl phthalic acid. Furthermore, it indicates the ester colors according to the iodine scale in milligrams iodine/100 ml., whereby 1 mg. iodine/100 ml. can be more or less compared with a dye number of 120 APHA. Since, the values are obtained with the same starting materials, it is possible to compare the color numbers. They show that with the same times, the amphoteric catalysis achieves better colors than in the reaction course containing catalytically effective acids. 

DEHP exposure of humans might result from intravenous administration of blood that has been stored in plastic containers, or through hemodialysis. Under situations such as these, in which DEHP is introduced directly into the blood, it is possible to evaluate exposure by measuring blood DEHP concentrations. DEHP metabolites, MEHP and phthalic acid, are also measured in the blood to determine exposure from medical products or devices (Barry et al. 1989 Sjoberg and Bondesson 1985). If the total amount of phthalate is to be monitored, the phthalate esters are first de-esterified (Liss et al. 1985). Techniques that measure total phthalic acid are not specific for DEHP exposure since other alkyl phthalic acid esters that are used as plasticizers will also produce phthalic acid after de-esterification. 

Cobalt catalysts completely dominated industrial hydroformylation rmtil the early 1970s, when rhodium catalysts were commercialized. Most aldehydes produced are hydrogenated to alcohols or oxidized to carboxylic acids. Esterification of the alcohols with phthalic anhydride produces dialkyl phtha-late plasticizers that are primarily used for polyvinyl chloride plastics - the largest single end-use. Detergents and surfactants make up the next largest category, followed by solvents, lubricants, and chemical intermediates. 

Decomposition of alkylbenzene Ph-Me, Ph-Et, Ph- Pr Friedel-Crafts acylation acetylation, benzoylation, and so on Isomerization of paraffin open-chain C1-C7, cyclic Cs-Cn Esterification -> AcOH + MeOH, EtOH, and so on CgOH + phthalic acid, and so on Cationic polymerization Me, Et, Bu vinyl ether Oligomerization 3-pinene, 1-octene, 1-decene Others -> aldol condensation, and so on... 

The analysis of phthalate metabolites has recently become of environmental concern. Primary metabolites of phthalate diesters are monoesters, in which one ester function is hydrolyzed. These monoesters have a carboxylic function that is currently derivatized to avoid adsorption during GC determination. Several derivatization agents have been used to block the free acid group. Methyl-esterification was used by Hashizume et al. and Suzuki et al. Silylation was preferred by Jonsson and Boren,and Jonsson et al. to simultaneously determine the diesters, monoesters and phthalic acid in the same analysis. Wahl et al. performed the analysis of three acid metabolites of... 

The first-order rate constant of the esterification of anhydrous phthalic acid catalyzed by nickel sulfates mounted on alumina and some other solid acids is shown in Table IV, together with the acidity of the catalysts measured by using p-dimethylaminoazobenezene as an indicator and the acidity calculated from the rate constants (cf. Section II). The catalytic activity correlates better with the acidity obtained by the latter method. The acidities measured by both methods coincide in the case of nickel sulfate, but do not in the case of silica-alumina. This is considered, according to Tarama et al., to be due to the fact that the Lewis acid sites which are assumed to be included in silica-alumina do not show catalytic activity. However, this might also be interpreted as due to the differences in acid strength and selectivity. 

Silica-alumina has a very strong acidity of pK —8.2, but metal sulfates do not show such a strong acidity, at what ever temperature they are heat-treated. Silica-alumina, whose acidity (0.6 mmole/gm) at pK +3.3 is much larger than the acidity (0.1 mmole/gm) of nickel sulfate at the same acid strength, was found to be much less catalytically active than the latter for the depolymerization of paraldehyde (57) and for the esterification of anhydrous phthalic acid (11). This might be interpreted thus acid of moderate strength is effective but too strong acid does not act as catalyst for the reactions. 

Esterification of Sucrose Chelates by Acid Anhydrides and Chlorides. Acetic, caprylic, stearic, maleic or phthalic acid anhydrides were added to a N,N-dimethylformamide (DMF) solution of a sucrose chelate in ratios of sucrose anhydride 1 1,3 or 1 3. 

Substituting formic, propionic, or butyric acid for acetic acid in the esterification reaction yields the corresponding formate, propionate, and butyrate esters. Lactic acid and oxalic acid (a difunctional acid) can also be reacted with alcohols to give the lactate and oxalate ester solvents. A versatile series of esters formed from the reaction of methanol with difunctional adipic, glutaric, and succinic acids yield the dibasic esters which are commonly referred to as DBE solvents. Reaction of lower aliphatic alcohols with t)-phthalic acid or phosphoric acid yield the corresponding phthalate and phosphate esters. Another important group of esters are obtained from the... 

Kienle and coworkers also found that phthalic acid gives similar results to phthalic anhydride and reacts at a similar rate once 50% esterification has been attained [42]. This is true since both reactions give a common intermediate product as shown in Eq. (3). 

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