Phthalic solvent effect

Solution equilibrium studies410 have identified both 1 1 and 1 2 complexes found between V02+ ions and oxalic acid, but only 1 1 complexes for phthalic, maleic, succinic, and adipic acids. Equilibrium constants for the formation and subsequent hydrolysis of these complexes have been determined. VO(H2L) (H5L = trihydroxy-glutaric acid) is the principal complex species in mixed aqueous acetone solutions but minor amounts of (VO)3(H2L)2 are also formed 411 the stability of VO(H2L)-increases with increasing acetone content. Solvent effects are also evident in vana-dium(iv)-quercetin system 412 the protonated ligand RH2 forms VOR+ and VR2 + in methanol at pH 3 but only VOR+ in aqueous methanol. 

The phthalic esters are the most important industrial plasticizers and, in practice, almost all commercially available aliphatic or cyclic alcohols are used in the production of phthalates. The standard plasticizer is diisooctyl phthalate (DOP), which represents a compromise between solvent effect, volatility and overall performance. Next to 2-ethylhexanol, isononyl alcohol and straight-chained C7 to C9-alcohols are used as standard components for phthalic esters. 

We attempted to solve this kinetically insoluble problem by using solvent effect. For this purpose various tertiary amines have been reacted with cyclic anhydrides in aprotic media [38,48]. (amines dimethylformamide, N,N -dimethylaniline, triethyl-amine, 1,4-diaza-[2,2,2] bicyclo-octane and pyridine anthydrides tetrachloroph-thalic, 3,6-dichlorophthalic, 3-nitrophthalic, 4-nitrophthalic, 3,5-dinitrophthalic, phthalic and 1,8-naphthalic). 

For the cydative cleavage step, it turned out that aprotic conditions were definitely superior to the use of protic media. Thus, employing N,N-dimethylformamide as solvent at somewhat elevated temperatures furnished the desired compounds in high yields and excellent purities. Having established the optimized conditions, various phthalic acids and amines were employed to prepare a set of phthalimides (Scheme 7.51). However, the nature of the amine was seen to have an effect on the outcome of the reaction. Benzyl derivatives furnished somewhat lower yields, probably due to the reduced activities of these amines. Aromatic amines could not be included in the study as auto-induced ring-closure occurred during the conversion of the polymer-bound phthalic acid. 

Solvent polarity influences the rate of copolymerization. Thus with increasing dielectric constant of the solvent, the copolymerization rate rises as a result of the increase in the dissociation constants of the active species. The apparent rate constant for the copolymerization of 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone with phthalic anhydride, initiated by hexadecyltrimethylammonium bromide56), increases from 4.65 x 10 4 s 1 in o-xylene to 6.84x 10 4 s-1 in nitrobenzene. Hilt et al.S4) proposed a suitable model illustrating the effect of solvent polarity in the copolymerization of phthalic anhydride with ethylene glycol carbonate in a mixture of nitrobenzene and trichlorobenzene (Table 4). With increasing fraction of the more polar nitrobenzene, the rate of copolymerization increases. 

Syntheses of MPc from phthalodinitrile or phthalic anhydride in the presence of urea are the two most important laboratory and industrial methods. They were also used originally by Linstead et al. [8,9], This procedure allows the production of many phthalocyanine compounds [35-37], Catalysts such as boric acid, molybdenum oxide, zirconium and titanium tetrachloride, or ammonium molybdate are used to accelerate the reaction and improve the yield [36,37], Ammonium molybdate is especially effective. Reaction is carried out either in a solvent or by heating the solid components. When metal chlorides and phthalodinitrile are used as starting materials, the reaction products are partially chlorinated (e.g.,7). 

Two processes are commonly used for the production of copper phthalocyanine the phthalic anhydride-urea process patented by ICI [33,34] and the I.G. Farben dinitrile process [48], Both can be carried out continuously or batchwise in a solvent or by melting the starting materials together (bake process). The type and amount of catalyst used are crucial for the yield. Especially effective as catalysts are molybdenum(iv) oxide and ammonium molybdate. Copper salts or copper powder is used as the copper source [35-37] use of copper(i) chloride results in a very smooth synthesis. Use of copper(i) chloride as starting material leads to the formation of small amounts of chloro CuPc. In the absence of base, especially in the bake process, up to 0.5 mol of chlorine can be introduced per mole of CuPc with CuCl, and up to 1 mol with CuCl2. 

Suzuki et al. [Ill] screened three solvents—methylene chloride, diethyl ether, and benzene—to determine their ability to produce optimum elution of phthalic acid monoesters sorbed on a styrene divinylbenzene polymer (Figure 2.40). The effect of elution solvent strength on the recovery of the free acid form of the monomethyl (MMP), ethyl (MEP), -propyl (MPRP), K-butyl (MBP), K-pentyl (MPEP), and -octyl (MOP) phthalates is compared. The phthalic acid monoesters are arranged in Figure 2.40 in the order of increasing number of carbons in the alkyl chain, which in turn is roughly correlated with an increase in hydrophobicity. 

Monoperoxyphthalic acid can be used for preparation of epoxides in the same way as peroxybenzoic acid. In general, good yields are obtained under almost the same conditions as with peroxybenzoic acid, but monoperoxyphthalic acid has the advantage that it is more stable. Because of this stability monoperoxyphthalic acid is particularly suited for epoxidation of less reactive olefins when reaction is effected in chloroform solution the phthalic acid produced is readily separated because it is insoluble in this solvent. 

Solubility. At long oil lengths, the aliphatic hydrocarbon chains of the fatty acids constitute the major portion of the mass of the resin molecules therefore, the resin is soluble in nonpolar aliphatic solvents. Conversely, as the oil length decreases and the phthalic content increases, the aromaticity of the resin molecules increases, and the aromaticity and/or the polarity of the solvent must be increased in order to dissolve the resin effectively. 

Cul NPs as efficient catalysts have been used for the preparation of H-pyrazolo[l,2-i]phthalazine-5,10-diones by the four-component condensation reaction of phthalic anhydride, hydrazine monohydrate, aromatic aldehydes, and malo-nonitrile or ethyl cyanoacetate under solvent-free conditions in good-to-excellent yields [39] (Scheme 5.9). The advantages offered by this method include short reaction times, excellent yields, simple procedure, easy workup, and the employment of a cost-effective catalyst. 

Plasticizers are high-boiling liquids which are solvents for PVC increasing addition reduces the Tg value of PVC until the material is rubbery, usually at levels above 30 phr by weight. Most commonly used plasticizers are Cg to C q derivatives of phthalic acid, e.g. dioctyl phthalate (DOP) and didecyl phthalate (DDP) the latter is less water-extractable, hence finding use for baby-pants. Phosphate plasticizers (e.g. trixylyl phosphate) are more expensive, more toxic but effectively enhance fire resistance. Aliphatic acid esters with Cg to C o are normally used in combination with phthalate plasticizers. 

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