Anhydrides, tables

Physical and Chemical Properties. Tables 5, 6, and 7 bst some of the physical and chemical properties of phthabc acid and its anhydride. Table 5. Physical Constants of Phthalic Acid and Phthalic Anhydride... 

Compared with standard diglycidyl ether resins, the liquid cyclic aliphatic resins are paler in colour and have a much lower viscosity. Whereas in general the cyclic aliphatic resins react more slowly with amines, there is less difference with acid anhydrides. Table 26.7 provides data illustrating this point. 

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. 

The enantioselectivity of the two-step process (deprotonation and trapping of the enolate) is considerably higher in the case of internal quenching with chlorotrimethylsilane as shown by the results of the external quenching of the lithium enolate with acetic anhydride (Table 4)20. 

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. 

The esterification of support-bound carboxylic acids has not been investigated as thoroughly as the esterification of support-bound alcohols. Resin-bound activated acid derivatives that are well suited to the preparation of esters include O-acylisoureas (formed from acids and carbodiimides), acyl halides [23,226-228], and mixed anhydrides (Table 13.15). A-Acylurea formation does not compete with esterifications as efficiently as it does with the formation of amides from support-bound acids. Esters can also be prepared from carboxylic acids on insoluble supports by acid-catalyzed esterification [152,229]. Alternatively, support-bound carboxylic acids can be esteri-fied by O-alkylation, either with primary or secondary aliphatic alcohols under Mitsu-nobu conditions or with reactive alkyl halides or sulfonates (Table 13.15). 

Other RE(OTf)3 were also examined as catalysts in the reaction of 1 with acetic anhydride (Table 2). Catalytic amounts of all the RE(OTf)3 listed effectively mediated the acylation of 1. Among these, scandium trifluoromethanesulfonate (scandium triflate, Sc(OTf)3)[6] or Yb(OTf)3 was superior to other RE(OTf)3 and afforded the acylation product 2 quantitatively. When, on the other hand, lanthanum trifluoromethanesulfonate (lanthanum triflate, La(OTf)3) was used, the yield of 2 was relatively low. The yields shown in Table 2 may reflect the catalytic activity of respective RE(OTf)3. 

Such oxides may therefore be considered as acid anhydrides. Table above shows a selection of oxoacids with their anhydrides and illustrates the conventional nomenclature. For example, sulphurous and sulphuric acids are display the lower (+4) and higher (+6) oxidation state, respectively, and their anions are called sulphite and sulphate. 

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. ... 

Chemical antigens known to stimulate immune responses in humans include formaldehyde, Isocyanates, acrylates, metals, sulfites, and anhydrides. Table 4.7 lists a number of these compounds. 

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

An efficient and ecofriendly procedure for the small-scale acylation of ferrocene with carboxylic acids is based on the in situ production of the mixed carboxylic-triflic anhydride (Table 4.15 see also Chapter 3). The reaction is simply performed by adsorbing ferrocene on the surface of activated alumina (preheated at 150°C for 3 h) and adding a mixture of carboxylic acid and trifluoroacetic anhydride (TFAA) at room temperature for a selected time. Products 40 are recovered in 55%-98% yield simply by elution with diethyl ether. 

SZ can be efficiently applied to the acylation of anisole, with a variety of anhydrides (Table 4.19), affording the para-isomers 47 in high yield, accompanied by a small amount of the ortho-isomers... 

O-C bonds in acids, esters and anhydride Table 6.3.3 O-C BDEs in Acids, Ethers and Anhydrides es ... 

Structural defects. Eventually, the mechanical strength properties and - in many cases - heat resistance are adversely affected. The unfavourable influence of the extended structure of ACECs is stronger in the case of amine curing in comparison with crosslinking with acid anhydrides (Table 13). 

Section 19.6 Esters occur naturally or are prepared from alcohols by Fischer esterification or by acylation with acyl chlorides or acid anhydrides (Table 19.3). 

Chemistry. Their chemistry is a fairly complex two-stage process. Typically, in the first stage, propylene glycol is mixed with maleic anhydride and phthalic anhydride (Table 3.17), and cooked 8 to 28 hr at 204 to 232°C to produce a molten prepolymer of Mn = 800 to 3000 (Fig. 3.15). This is mixed with st5trene monomer to pro-... 

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