Phthalic anhydride

About: Phthalic anhydride is a research topic. Over the lifetime, 5261 publications have been published within this topic receiving 48697 citations. The topic is also known as: 2-benzofuran-1,3-dione & isobenzofuran-1,3-dione.

Performance of nano-Co3O4/peroxymonosulfate system: Kinetics and mechanism study using Acid Orange 7 as a model compound

Abstract: Nano-Co 3 O 4 was prepared by precipitation method and was successfully applied as heterogeneous catalyst to activate peroxymonosulfate (PMS) and degrade a model compound Acid Orange 7 (AO7). The catalyst exhibits spherical morphologies with minor particle agglomeration, small particle average size (20 nm) and high specific surface area (18 m 2 /g). The degradation kinetics of AO7 induced by nano-Co 3 O 4 /PMS system was investigated at both acidic and neutral pH conditions. The heterogeneous character of PMS activation with nano-Co 3 O 4 is more pronounced at neutral pH as indicated by fast degradation rate of AO7 and low dissolved Co ion. The catalyst presented a long-term stability through using the catalyst for multiple runs in the degradation of AO7. The main degradation intermediates of AO7 identified by GC/MS and LC/MS were 4-hydroxybenzenesulfonic acid, 1,2-naphthalenedione, coumarin, phthalic anhydride, phthalimide and 2-formyl-benzoic acid. Proposed degradation pathways were elucidated in light of the analyzed degradation products and frontier electron density theory.

Chemospecific manipulations of a rigid polysaccharide: syntheses of novel chitosan derivatives with excellent solubility in common organic solvents by regioselective chemical modifications

Abstract: Efficient procedures for the preparations of soluble chitosan derivatives have been established on the basis of the regioselective chemical modifications. Selective and quantitative N-phthaloylation of chitosan proceeds smoothly by the reaction of chitosan with phthalic anhydride in N,N-dimethylformamide (DMF) at 130 "C. The resulting phthaloylchitosan exhibits much improved solubility in common organic solvents such as DMF, NJV-dimethylacetamide, dimethyl sulfoxide, and pyridine. The enhanced solubility of new types of chitosan derivatives under homogeneous reaction conditions. Facile conversions of phthaloylchitosan, a key starting material, into several 6-0-substituted derivatives are carried out by the reactions with bulky substituents such as triphenylmethyl (trityl) and @-tolylsulfony1)oxy (tosyloxy) groups. These reactions also proceed in homogeneous solution under mild conditions, and the degrees of substitution are estimated to be 1.0. Subsequent 3-0-acetylation of the secondary hydroxyl groups of 6-0-substituted materials gives rise to regioselectively modified chitosan derivatives showing much better solubility. Specific N-dephthaloylation or 0-detritylation of 6-0-trityl derivatives affords versatile intermediates, which permit the introduction of additional functional groups regioselectively.

Synthesis of Fluorinated Fluoresceins

Abstract: Several novel fluorinated fluoresceins (Oregon Green dyes) were prepared by the reaction of fluororesorcinols with phthalic anhydride and its derivatives. A novel regiospecific synthesis of fluororesorcinols was key to the successful synthesis of these new fluorophores. (Polyfluoro)nitrobenzenes were reacted with 2 equiv of sodium methoxide followed by reduction, hydrodediazoniation, and demethylation, giving the first straightforward synthesis of 2-fluororesorcinol, 4-fluororesorcinol, 2,4-difluororesorcinol, and 2,4,5-trifluororesorcinol. These fluorinated fluoresceins have higher photostability and ionize at a lower pH (pKa = 3.3−6.1) than fluorescein (pKa = 6.5). Some of the fluorinated fluoresceins have very high quantum yields (0.85−0.97), which, in combination with their lower pKas and high photostability, makes them superior fluorescent dyes for use as reporter molecules in biological systems.