Maleic anhydride, Table

Reaction of 1,2 -dicarboxylic acids has been used for the formation of a number of strained alkenes and also applied to the Diels-Alder addition products from maleic anhydride (Table 9.5). Both cis- and tr s-diacids take part in the process. Aqueous pyridine containing, triethylamine as a strong base, is considered the best solvent and higher yields are obtained at temperatures of around 80 "C [130]. Use of a divided cell avoids a possibility of electrocatalytic hydrogenation of the product at the cathode. The addition of /a/-butylhydroquinone as a radical scavenger prevents polymerization of the product [127], An alternative chemical decarboxylation process is available which uses lead tetraacetate [131] but problems can arise because of reaction between the alkene and lead tetraacetate. 

Although a variety of synthesis, compositions and reactor parameters were studied, the P-V-0 catalysts in the temperature series were synthesized in the up flow HTAD reactor using a 0.12 M solution of anunonium vanadate in water which contained the required amount of 85% phosphoric acid to result in a 1.2/1.0 P/V atom ratio. This atom ratio is normally preferred for the most selective oxidation of butane to maleic anhydride. Table I shows that the P/V atom ratios obtained for the analyzed, finished (green colored) catalysts were approximately the same as the feed composition when a series of preparations were studied between 350 C and 800°C. This was typical for all of the catalysts synthesized under a variety of conditions. 

A variety of techniques have been used in the present work to establish the relative sensitivity of positive electron-beam resists made from copolymers of maleic anhydride (Table I). The term sensitivity is used rather loosely at times. In the most practical sense, sensitivity is a comparative measure of the speed with which an exposure can be made. Thus, the exposure conditions, film thickness, developing solvent and temperature may be involved. Most often, the contrast curve is invoked as a more-or-less objective measure of sensitivity. The dose needed to allow removal of exposed film without removing more than about 70% of the unexposed film can be a measure of sensitivity. The initial film thickness and the developing conditions still must be specified so that this measure is not, strictly speaking, an intrinsic property of the polymeric material. 

With its concerted mechanism implying little charge distribution change along the pathway, the Diels-Alder reaction has been understood to have little rate dependence on solvent choice. For example, the relative rate of cyclopentadiene dimerization increases only by a factor of 3 when carried out in ethanol. The relative rate for the Diels-Alder reaction of isoprene with maleic anhydride (Table 7.1) varies by only a factor of 13 with solvents whose dielectric constants vary by almost a factor of 10, but the rate acceleration is not a simple function of the solvent polarity. Furthermore, the dimerizations of cyclopentadiene and 1,3-butadiene proceed at essentially identical rates in the gas and solution phases. ... 

Integrate series is represented by HDPE- and linear low density polyethylene (LLDPE)-functionalized maleic anhydride (Table 5.2)... 

Cyclooctatetraene A exists in equilibrium with less than 0.05% of a bicychlic isomer B, which is trapped by Diels-Alda- cycloaddition to 2-butenedioic anhydride (maleic anhydride. Table 14-1) to give compound C. 

Butyrolactone. y-Butyrolactone [96-48-0] dihydro-2(3H)-furanone, was fkst synthesized in 1884 via internal esterification of 4-hydroxybutyric acid (146). In 1991 the principal commercial source of this material is dehydrogenation of butanediol. Manufacture by hydrogenation of maleic anhydride (147) was discontinued in the early 1980s and resumed in the late 1980s. Physical properties are Hsted in Table 4. 

Table 1. Physical Properties of Maleic Anhydride, Maleic Acid, and Fumaric Acid...

Table 4. World Maleic Anhydride Capacity by Reactor Type...

Data for the production and sales of maleic anhydride and fumaric acid ia the United States between 1979 and 1992 are shown ia Table 5. Production of maleic anhydride during this time grew - 2% on average per year. Production of fumaric acid has declined during the same period as customers have switched to the less cosdy maleic anhydride when possible. All production of maleic anhydride in the United States in 1992 was from butane-based plants which used fixed-bed reactor technology as shown in Table 6. The number of fumaric acid producers has been reduced considerably since the early 1980s with only two producers left in the United States in 1992 as shown in Table 6. Pfizer shut down its fumaric acid plant at the end of 1993. However, Bartek of Canada will start up an expanded fumaric acid faciUty to supply the North American market for both their own and Huntsman s requirements. 

Table 6. Producers of Maleic Anhydride and Fnmaric Acid in the United States, 1992 ...

Capacities of maleic anhydride faciUties worldwide are presented in Table 7. The switch of feedstock from benzene to butane was completed in the United States in 1985, being driven by the lower unit cost and lower usage of butane in addition to the environmental pressures on the use of benzene. Worldwide, the switch to butane is continuing with 58% of the total world maleic anhydride capacity based on butane feedstock in 1992. This capacity percentage for butane has increased from only 6% in 1978. In 1992, 38% of the total world maleic anhydride capacity was based on benzene feedstock and 4% was derived from other sources, primarily phthaUc anhydride by-product streams. 

Maleic anhydride itself has few, if any, consumer uses but its derivatives are of significant commercial interest (161). The distribution of end uses for maleic anhydride is presented in Table 9 for the year 1992 (182). The majority of the maleic anhydride produced is used in unsaturated polyester resin (see Polyesters, unsaturated). Unsaturated polyester resin is then used in both glass-reinforced appHcations and in unreinforced appHcations as shown in Table 10 (183). 

Maleic anhydride is used in a multitude of appHcations in which a vinyl copolymer is produced by the copolymerization of maleic anhydride with other molecules having a vinyl functionaHty. Typical copolymers and their end uses are Hsted in Table 11. 

Table 11. Maleic Anhydride Copolymers with Vinyl Functionality...

The properties of polymers formed by the step growth esterification (1) of glycols and dibasic acids can be manipulated widely by the choice of coreactant raw materials (Table 1) (2). The reactivity fundamental to the majority of commercial resins is derived from maleic anhydride [108-31-6] (MAN) as the unsaturated component in the polymer, and styrene as the coreactant monomer. Propylene glycol [57-55-6] (PG) is the principal glycol used in most compositions, and (i9f2v (9)-phthahc anhydride (PA) is the principal dibasic acid incorporated to moderate the reactivity and performance of the final resins. 

Dicylopentadiene Resins. Dicyclopentadiene (DCPD) can be used as a reactive component in polyester resins in two distinct reactions with maleic anhydride (7). The addition reaction of maleic anhydride in the presence of an equivalent of water produces a dicyclopentadiene acid maleate that can condense with ethylene or diethylene glycol to form low molecular weight, highly reactive resins. These resins, introduced commercially in 1980, have largely displaced OfXv o-phthahc resins in marine apphcations because of beneficial shrinkage properties that reduce surface profile. The inherent low viscosity of these polymers also allows for the use of high levels of fillers, such as alumina tfihydrate, to extend the resin-enhancing, fiame-retardant properties for apphcation in bathtub products (Table 4). 

MVE/MAN Copolymers. Various mol wt grades of poIy(methyI vinyl ether-i o-maleic anhydride) (PMVEMA) are available from International Specialty Products, Inc. (formerly GAF Corp.), under the trade name of Gantrez. Table 6 illustrates the M. and MWD found for commercially available polymers. As can be seen, high molecular weights are readily achieved. 

The Q and e values of VP are 0.088 and —1.62, respectively (125). This indicates resonance interaction of the double bond of the vinyl group with the electrons of the lactam nitrogen, whence the electronegative nature. With high e+ monomers such as maleic anhydride, VP forms alternating copolymers, much as expected (126). With other monomers between these Q and e extremes a wide variety of possibiHties exist. Table 14 Hsts reactivity ratios for important comonomers. 

Copolymers of 9-vinyladenine and acrylamide, 21 (PA-A), l-vinylthymine and acrylamide, 22 (PT A) and 1-vinyluracil and maleic anhydride, 23(PU-MA) were also synthesized21. The hypochromicities with RNA were measured and compiled in Table 3. 

The cycloaddition between norbornadiene (23 in Scheme 1.12) and maleic anhydride was the first example of a /mmo-Diels-Alder reaction [55]. Other venerable examples are reported in Scheme 1.12 [56]. Under thermal conditions, the reaction is generally poorly diastereoselective and occurs in low yield, and therefore several research groups have studied the utility of transition metal catalysts [57]. Tautens and coworkers [57c] investigated the cycloaddition of norbornadiene and some of its monosubstituted derivatives with electron-deficient dienophiles in the presence of nickel-cyclo-octadiene Ni(COD)2 and PPhs. Some results are illustrated in Tables 1.4 and 1.5. 

The investigation on the use of K-10 montmorillonite under free solvent conditions was then extended to inner ring dienes such as furan and its 2,5-dimethyl derivative [9] (Table 4.3). The cycloadditions generally proceed slowly, and Zn(II)-doped clay and microwave irradiation were used to accelerate the reactions. The reaction with maleic anhydride preferentially affords the thermodynamically favored exo adduct. 

Fallis and coworkers studied Jt-facial selectivity in the reactions of series of 5-substituted 1,2,3,4,5-pentamethylcyclopentadienes Cp -X. They reported that the diene 5 (Cp -X X = SCH3) with maleic anhydride proceeded more slowly than that of the 5-oxygen substituted cyclopentadienes 6 and 7 (Cp -X X = OH, OCH3), where the HOMO of the diene 5 lies higher than those of 6 and 7 [7, 8] (Table 2). These results seemed to suggest that in the case of the reaction of 5 the NHOMO considerably contributed to the reactions. 

Table 4 PM3 calculation of 5-X-cyclopentadenes at the transition states of Diels-Alder reactions with maleic anhydride...

Table 5 AMI Calculation of the transition states in Diels-Alder reactions between 5-X-pentamethylcyclopentadiones and maleic anhydride...

Synthetic polymers and natural polymers suitable for drilling muds are listed in Tables 1-7 and 1-8, respectively. Polyacrylamides are eventually hydrolyzed in the course of time and temperature. This leads to a lack of tolerance toward electrolyte contamination and to a rapid degradation inducing a loss of their properties. Modifications of polyacrylamide structures have been proposed to postpone their thermal stability to higher temperatures. Monomers such as AMPS or sulfonated styrene/maleic anhydride can be used to prevent acrylamide comonomer from hydrolysis [92]. 

Corrosion inhibiting compositions for metals subjected to highly acidic environments may be produced by reacting in a condensation reaction a styrene/ maleic anhydride copolymer with a polyamine to produce a polyimidoamine inhibitor [1568]. These inhibitors exhibit film-forming and film-persistency characteristics. Some relevant polyamines are listed in Table 6-2. 

In order to extend the scope of the reaction, and with the aim of designing a greener approach to the above set of reactions, we preformed the acylation of the same substrates with different acylation agents, such as maleic anhydride, p-methoxybenzoic acid and acetic acid (Scheme 48.4). Table 48.3 shows the results for acylation of benzenesulfonamide. 

Ethoxy)-allylidenecyclopropane (136a) readily underwent Diels-Alder reaction with activated dienophiles under mild conditions (Table 14) [33]. Only one regioisomer was formed with unsymmetrically substituted dienophiles such as methyl maleic anhydride (137), and quinones 138-141 (entries 2 and 3-6). AH the cycloadducts 143-147 derive from an endo approach between the two reagents. Two site-isomers were obtained in 96 4 ratio with 3-isopropyl-6-methyl-p-quinone (141) (entry 6) and the high site-selectivity observed in this... 

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