Phthalic Anhydride (phthalic + anhydride)

Distribution by Scientific Domains

Selected Abstracts

Hydrolysis of Amides to Carboxylic Acids Using Phthalic Anhydride under Microwave Irradiation and Solvent-Free Conditions.

CHEMINFORM, Issue 36 2005
No abstract is available for this article. [source]

Effects of mixed aqueous-organic solvents on the rate of intramolecular carboxylic group-catalyzed cleavage of N -(4,-methoxyphenyl)phthalamic acid

Sim Yoke Leng
Kinetic study on the cleavage of N -(4,-methoxyphenyl)phthalamic acid (NMPPAH) in mixed H2O-CH3CN and H2O-1,4-dioxan solvents containing 0.05 M HCl reveals the formation of phthalic anhydride (PAn)/phthalic acid (PA) as the sole or major product. Pseudo first-order rate constants (k1) for the conversion of NMPPAH to PAn decrease nonlinearly from 60.4 10,5 to 2.64 10,5 s,1 with the increase in the contents of 1,4-dioxan from 10 to 80% v/v in mixed aqueous solvents. The rate of cleavage of NMPPAH in mixed H2O-CH3CN solvents at ,50% v/v CH3CN follows an irreversible consecutive reaction path: NMPPAH PA. The values of k1 are larger in H2O-CH3CN than in H2O-1,4-dioxan solvents. 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 316,325, 2004 [source]

Thermal stability of surfactants with amino and imido groups in poly(ethylene terephthalate)/clay composites

Xuepei Yuan
Abstract Effects of thermal stability of surfactants with amino and imido groups on thermal properties of poly(ethylene terephthalate) (PET)/clay composites were studied. The imidosilane surfactant was synthesized successfully from the imide reaction between amino silane and phthalic anhydride. TGA shows that imidosilane decomposition behaviors have two major stages according to the degradations of different functional groups. After melt extrusion, the decomposition of amino functional groups in amino surfactants decreases the thermal stability of organoclay and accelerates the degradation behaviors of PET composites. Because of the enhanced thermal stability of imidosilane surfactants, PET/imido-palygorskite (PT) composites represent enhanced thermal stability, good dispersion and low thermal expansion. 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Synthesis, characterization and biological activity of some 1,2,4-triazine derivatives

A. A. El-Barbary
4-Amino-6-methyl-3-(2H)-thioxo-5-(4H)-oxo-1,2,4-triazine (1) was condensed with 2-methyl (or phenyl)-4H -3,1-benzoxazin-4-one (5a,b) in boiling acetic acid to give compounds 8-11. Reacting 1 with chloroacetyl chloride afforded the corresponding chloroacetamido and triazinothiadiazine derivatives 12 and 13. Condensing 2 with succinic anhydride and/or phthalic anhydride yielded compounds 14 and 15. Benzoylation of 4-amino-6-methyl-3-(2H)-thioxo-5-(4H)-oxo-2-(2,3,4,5-tetra- O -acetyl-,-D-glucopyra-nosyl)-1,2,4-triazine (19) afforded the corresponding 4- N,N -dibenzoyl derivative 20. Deblocking of the N -2 glycoside 21 and the S -glycoside 22 by methanolic ammonia gave compounds 23 and 24. Acetylation of 4-amino glycoside 25a afforded the corresponding 4-mono- and 4-diacetyl derivatives 26 and 27. Deamination of 25a,b yielded compounds 28a,b. Methylation of compound 28b afforded the corresponding N4- and S -methyl derivatives 29 and 30. [source]

Synthesis and reactions of 3-amino-2-methyl-3H -[1,2,4]triazolo[5,1- b]-quinazolin-9-one and 2-hydrazino-3-phenylamino-3H -quinazolin-4-one

Mohamed A. Saleh
The reaction of 3- N -(2-mercapto-4-oxo-4H -quinazolin-3-yl)acetamide (1) with hydrazine hydrate yielded 3-amino-2-methyl-3H -[1,2,4]triazolo[5,1- b]quinazolin-9-one (2). The reaction of 2 with o -chlorobenzaldehyde and 2-hydroxy-naphthaldehyde gave the corresponding 3-arylidene amino derivatives 3 and 4, respectively. Condensation of 2 with 1-nitroso-2-naphthol afforded the corresponding 3-(2-hydroxy-naphthalen-1-yl-diazenyl)-2-methyl-3H -[1,2,4]triazolo[5,1- b]quinazolin-9-one (5), which on subsequent reduction by SnCl2 and HCl gave the hydrazino derivative 6. Reaction of 2 with phenyl isothiocyanate in refluxing ethanol yielded thiourea derivative 7. Ring closure of 7 subsequently cyclized on refluxing with phencyl bromide, oxalyl dichloride and chloroacetic acid afforded the corresponding thiazolidine derivatives 8, 9 and 10, respectively. Reaction of 2-mercapto-3-phenylamino-3H -quinazolin-4-one (11) with hydrazine hydrate afforded 2-hydrazino-3-phenylamino-3H -quinazolin-4-one (12). The reactivity 12 towards carbon disulphide, acetyl acetone and ethyl acetoacetate gave 13, 14 and 15, respectively. Condensation of 12 with isatin afforded 2-[N -(2-oxo-1,2-dihydroindol-3-ylidene)hydrazino]-3-phenylamino-3H -quinazolin-4-one (16). 2-(4-Oxo-3-phenylamino-3,4-dihydroquinazolin-2-ylamino)isoindole-1,3-dione (17) was synthesized by the reaction of 12 with phthalic anhydride. All isolated products were confirmed by their ir, 1H nmr, 13C nmr and mass spectra. [source]

Effects of non-ionic and mixed cationic,non-ionic micelles on the rate of alkaline hydrolysis of phthalimide

M. Niyaz Khan
Abstract Pseudo-first-order rate constants (kobs) for the alkaline hydrolysis of phthalimide (PTH) show a monotonic decrease with the increase in [C16E20]T (total concentration of Brij 58) at constant [CH3CN] and [NaOH]. This micellar effect is explained in terms of the pseudophase model of micelles. The rate of hydrolysis of PTH in C16E20 micellar pseudophase appears to be negligible compared with that in the aqueous pseudophase. The values of kobs for C12E23 (Brij 35) show a sharp decrease at very low values of [C12E23]T followed by a very slow decrease with increase in [C12E23]T at relatively higher values of the latter. The rate of hydrolysis becomes too slow to monitor at [C12E23]T ,0.04,M in the absence of cetyltrimethylammonium bromide (CTABr) and at [C12E23]T ,0.05,M in the presence of 0.006,0.02,M CTABr at 0.02,M NaOH whereas such characteristic behavior is kinetically absent with C16E20. The values of kobs, obtained at different [NIS]T (where NIS represents C16E20 and C12E23) in the presence of a constant amount of CTABr, follow the empirical relationship kobs,=,(k0,+,kK[NIS]T)/(1,+,K[NIS]T) where k and K are empirical parameters. The values of k are only slightly affected whereas the values of K decrease with increase in [CTABr]T for the mixed C16E20,CTABr micellar system. The rate of hydrolysis of PTH at ,0.01,M C12E23 and ,0.01,M CTABr reveals the formation of phthalic anhydride whereas this was not observed in the mixed C16E20,CTABr micellar system under similar experimental conditions. Copyright 2002 John Wiley & Sons, Ltd. [source]

Synthesis of soluble branched polyimides derived from an ABB, monomer

Kun-Li Wang
Abstract A novel ABB, monomer, an isomeric mixture of 4-[4-(2,4-diaminophenoxy)phenoxy]phthalic acid 2-methyl ester, was successfully prepared. The direct polycondensation of the ABB, monomer was carried out to form polyamic acid monomethyl ester as a precursor with an inherent viscosity of 0.30 dL/g and a number-average molecular weight of 12,000. The degree of branching of the precursor, determined by 1H NMR, was 0.07. The low degree of branching was caused by the differences in the reactivities of the amino groups. The shape factor was calculated to be 0.72. End-modified reactions with acetyl chloride, benzoyl chloride, and phthalic anhydride were carried out. After the chemical imidization of the end-modified precursors, end-modified polyimides were successfully prepared. The end-modified polyimides were soluble in dimethyl sulfoxide, dimethylformamide (DMF), and N -methyl-2-pyrrolidinone. On the basis of thermogravimetry and differential scanning calorimetry measurements of the polyimides, the 5 wt % thermal loss temperatures were determined to be 400,520 C, and the glass-transition temperatures were determined to be 200,258 C. According to the X-ray diffraction measurements, the end-modified polyimides were amorphous. A strong but brittle film was prepared from an acetamide end-modified polyimide solution, via casting from a DMF solution, with a tensile strength of 46 MPa, an elongation at break of 4%, and a modulus of 1.3 GPa. 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3200,3211, 2004 [source]

Polycondensation of lactic acid catalyzed by organic acid anhydrides

Yanbin Bai
Abstract Poly(lactic acid) was prepared by the utilization of the acid anhydrides cis -butenedoic anhydride, phthalic anhydride and pyromellitic dianhydride as catalysts. The effect of the amount of catalyst, temperature and reaction time on the polymerization was investigated in detail. The results show that the acid anhydride catalysts are very efficient in bulk polycondensation, giving poly(D,L -lactic acid) with average molecular weights (Mw) of (1.7,2.3) 104 in high yield. Copyright 2007 Society of Chemical Industry [source]

New aspects of unsaturated polyester resin synthesis.

Part 2.
Abstract The distribution of unsaturations in the prepolymer of a typical unsaturated polyester (UP) resin (maleic anhydride, phthalic anhydride and 1,2-propylene glycol) has been shown to influence the kinetics of the cure process with styrene monomer. Segments containing double bonds in close proximity appear to lower the reactivity of the resin due to steric hindrance, as indicated by the fact that the rate of cure and the final degree of cure, measured by differential scanning calorimetry (DSC), increase as the average sequence length (SL) of maleic units decreases. This implies that the reactivity of UP resins may be improved by synthesis of prepolymers with certain reactant sequence-length distributions. The copolymer formed by the melt condensation process of maleic anhydride, phthalic anhydride and 1,2-propylene glycol in the absence of a transesterification catalyst has a non-random structure with a tendency towards blockiness. This was established using 1H NMR analysis in tandem with deterministic and Monte Carlo modelling techniques. Copyright 2003 Society of Chemical Industry [source]

Synthesis of 5-Substituted 2-Methylbenzimidazoles with Anticancer Activity

Sh. I. El-Naem
Abstract A series of compounds comprising the thiocarboximidopyrazolyl 5, the phenylpyrazolyl 6, the dimethylpyrazolyl 7, the nitrophenylpyrazolyl 8, the dimethyloxazolyl 9, the benzoxazepinyl 10, and pyrimidyl 11 a,c derivatives of 3-(2-methyl-1H -benzimidazol-5-ylazo)pentane-2, 4-dione was synthesized. Moreover, 5-amino-2-methylbenzimidazole (3) was reacted with phthalic anhydride or maleic anhydride in acetic acid or in toluene to produce 12,15. Treating 5, 6-diamino-2-methylbenzimidazole (16) with ethyl cyanoacetate or diethyl malonate or acetyl acetone leads to the formation of the benzodiazepine derivatives 17,20. The cytotoxic activity of the compounds 2, 7, 9, 10, and 11 was tested against 60 types of human cancer cell lines. Compounds 7 and 9 were found to be the most potent. [source]

Electrochemical Oxidation of Benzoic Acid Derivatives on Boron Doped Diamond: Voltammetric Study and Galvanostatic Electrolyses

B. Louhichi
Abstract The electrochemical oxidation of aqueous wastes polluted with benzoic and salicylic acids and phthalic anhydride on boron-doped diamond electrodes has been studied. The complete mineralization of the organic waste has been obtained in each case regardless of the nature of the compound, composition of the solution, and current density. Different voltammetric behaviors between benzoic acid, salicylic acid, and phthalic anhydride were obtained in the voltammetric study, but no differences in the electrochemical oxidation of the three compounds seems to exist in the bulk electrolyses study. The total mineralization of the three compounds at different current densities confirms that the oxidation must occur directly on the electrode surface and/or by hydroxyl radicals generated by decomposition of water and/or by other oxidants electro-generated from the sulfate oxidation. [source]