117-21-5Relevant academic research and scientific papers
Method of making halophthalic acids and halophthalic anhydrides
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Page/Page column 9, (2008/06/13)
A method of preparing a halophthalic acid is disclosed which comprises the steps of contacting in a liquid phase reaction mixture at least one halogen-substituted ortho-xylene with oxygen and acetic acid at a temperature in a range between about 120° C. and about 220° C. in the presence of a catalyst system yielding a product mixture comprising less than 10 percent halogen-substituted ortho-xylene starting material, a halophthalic acid product, and less than about 10,000 ppm halobenzoic acid and less than about 1000 ppm halophthalide by-products based on a total amount of halophthalic acid present in the product mixture. In addition a method for the preparation of halophthalic anhydride is also disclosed.
Processes using a phosphorus complex
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, (2008/06/13)
A process for chlorinating compounds containing a carbon atom bonded to a hetero-atom selected from the group consisting of oxygen, nitrogen and sulfur; said process comprises contacting the carbon hetero-atom containing compound with a chloro phosphorus complex of the formula wherein R is selected from the group consisting of aryl, substituted aryl, alkyl and substituted alkyl, so that the hetero-atom is replaced by at least one chlorine atom; compounds capable of being chlorinated can include, for example, carboxylic acids, acid chlorides, ketones, aldehydes, alcohols, epoxides, esters, anhydrides, ethers, thiols, and aromatic nitro groups; the reaction can be extended to compounds containing the carbon to chlorine bond alpha to a carbon atom containing at least one hydrogen atom, it can be further dehydrochlorinated, e.g., by either heating to a temperature ranging from about 50° C. to about 300° C. or by reaction with a base selected, e.g., from alkali metal hydroxides and alkoxides.
On the regioselectivity of metal hydride reductions of 3-substituted phthalic anhydrides
Soucy,Favreau,Kayser
, p. 129 - 134 (2007/10/02)
A problem of 3-methoxyphthalide reduction by metal hydrides was reinvestigated. Various effects controlling selectivity of reductions in 3-substituted phthalides were studied, and a qualitative interpretation of the results is now proposed. Methods for obtaining enhanced yields of one or the other lactonic product were developed.
Flame retardant for polymeric compositions
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, (2008/06/13)
An additive flame retardant bisimide containing halogen atoms and ammonium acid tetrahalophthalate, e.g. N,N'-bis(2-ethylene tetrabromophthalimide) ammonium acid tetrabromophthalate. These compounds are useful in a variety of polymeric compositions and demonstrate increased thermal stability. They also foam on decomposition with the evolution of gas thus readily lending themselves to the preparation of flame retardant coatings.
Remarkably Selective Chlorination of Phthalic Anhydride and Its Monochlorinated Derivatives
Verbicky, John W.,Williams, Louella
, p. 2465 - 2468 (2007/10/02)
The vapor-phase chlorination of phthalic anhydride 1 and its monochlorinated derivatives 2 and 3 in the temperature range from 390 to 600 deg C with elemental chlorine has been investigated and found to be highly selective.Thus, chlorination of 1 in the temperature range from 390 to 450 deg C was found to give high yields of monochlorinated products accompanied by only small amounts of dichlorination with a high degree of regioselectivity favoring the formation of 4-chlorophthalic anhydride.Chlorination of a 3-chlorophthalic anhydride 3 by this method has provided thefirst direct synthesis of 3,5-dichlorophthalic anhydride 7 from phthalic anhydride via chlorination.
The Schmidt reaction of anthraquinones
Flemming, Cecily A.,Gandhi, Sham S.,Gibson, Martin S.,Ruediger, Edward H.
, p. 624 - 628 (2007/10/02)
Schmidt reaction (sodium azide/sulfuric acid) of 1,5- and of 1,8-dichloroanthraquinones gives, in each case, both of the theoretically possible lactams (2,3,5,6-dibenzoazepin-4,7-diones).Two of the four theoretically possible lactams have been identified from Schmidt reaction of 1- and 2-chloroanthraquinones respectively.Methods used include:(a) preferential hydrolysis of one lactam and identification of the isomeric aminoanthraquinone formed on cyclodehydration of the resulting amino acid; (b) identification of the isomeric aminoanthraquinone(s) formed on direct treatment of a lactam (or mixture of lactams) by sulfuric acid; (c) cleavage by potassium tert-butoxide of the amino acid formed by preferential hydrolysis of one lactam and identification of the resulting benzoic acid as its methyl ester.
Aspects of Tautomerism: Part X - Neighbouring Group Effects on the Structure and Reactivity Patterns of Acid Chlorides
Bhatt, M. Vivekananda,El Ashry, Shaker H.,Somayaji, Vishwanatha
, p. 473 - 486 (2007/10/02)
The influence of neighbouring groups on the structure and reactivity patterns of over one hundred acid chlorides derived from γ- and δ-keto acids, 1,2- and 1,3-dicarboxylic acid half-esters and diacid chlorides have been examined.Contrary to reports in the literature, text books and monographs, evidence has been obtained for the non-existence of tautomerism between the isomeric pairs of either acid chlorides or half-ester acid chlorides.ce.
