- Preparation method for pyromellitic dianhydride
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The invention discloses a preparation method for pyromellitic dianhydride. The preparation method comprises the following steps: (1) reacting metachlorotoluene and dichloroethane for 0.5 to 5 hours inan organic solvent under the catalytic action of aluminium trichloride or ferric chloride, generating 2,2'4,4'5,5'-hexamethyldiphenyl ethane, hydrolysing, and removing the solvent to obtain a crude product of the 2,2'4,4'5,5'-hexamethyldiphenyl ethane; and (2) heating and gasifying the crude product of the 2,2'4,4'5,5'-hexamethyldiphenyl ethane, oxidizing through air at the reaction temperature of 350 to 500 DEG C under the action of a catalyst, and collecting the product to obtain the pyromellitic dianhydride. According to the preparation method for the pyromellitic dianhydride disclosed bythe invention, the product selectivity can reach over 90 percent, the yield is good, the cost is low, and industrial production can be realized.
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Paragraph 0012; 0026; 0029; 0030; 0033; 0036
(2019/05/02)
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- MOLECULAR PROBES FOR CHEMILUMINESCENCE IMAGING AND IN VIVO DETECTION OF TARGET MOLECULES
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Chemiluminescence imaging probes for in vivo detection of biological molecules, events, or processes. The CLI probes may feature a portion of a fluorescein molecule and a portion of a luminol molecule. The fluorescein molecule and luminol molecule may be linked by a non-xanthenic aromatic ring. The CLI probes are generally non-toxic and soluble in aqueous solutions such as PBS. The CLI probes may be used to detect specific molecules in vivo.
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Paragraph 0047
(2016/12/22)
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- METHOD FOR PRODUCING CARBOXYLIC ACID ANHYDRIDE, METHOD FOR PRODUCING CARBOXYLIC IMIDE, AND METHOD FOR MANUFACTURING ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBER
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A method for producing a carboxylic acid anhydride includes heating a composition containing a specific compound in a solvent to yield the carboxylic acid anhydride. The solvent is an aprotic polar solvent having a boiling point of 50° C. or more.
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Paragraph 0115
(2017/01/19)
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- Thermal stability of ionic nets with CuII ions coordinated to di-2-pyridyl ketone: Reversible crystal-to-crystal phase transformation
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Supramolecular networks are crystalline materials based on connections between metal ions through organic ligands. In this sense, the combination of polycarboxylate anions and dipyridyl ligands is an effective strategy to produce extended structures. However, sometimes the 3D arrangement results in an ionic network, and this is the case for the novel compounds [Cu((py)2C(OH)2)2](H2bta) (1) and [Cu((py)2C(OH)2)2](fum) (2) where (py)2C(OH)2 is the gem-diol of di-2-pyridyl ketone ((py)2CO), H2bta2- is the divalent anion of 1,2,4,5-benzenetetracarboxylic acid (H4bta), and fum2- is the divalent anion of fumaric acid (butenedioic acid). Both compounds were synthesized and structurally characterized by means of single crystal X-ray diffraction and IR spectroscopy. The thermal behavior of both compounds was analyzed through TG/DTA and TDX, concluding that the thermal stability is influenced by the dehydration of the coordinated molecules and counter-anions. Additionally, 13C NMR measurements were performed to analyze the reversible crystal-to-crystal phase transformation observed for 1.
- Bravo-García, Laura,Barandika, Gotzone,Bazán, Bego?a,Urtiaga, Miren Karmele,Arriortua, María Isabel
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p. 117 - 123
(2015/04/22)
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- A visual volumetric hydrogel sensor enables quantitative and sensitive detection of copper ions
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We propose a visual volumetric sensor with 5,6-dicarboxylic fluorescein cross-linked amine-functionalized polyacrylamide hydrogel. The sensor undergoes volume response to Cu2+ ions at the μM level, which enables naked-eye quantitative detection by reading the graduation on a pipette.
- Wu, Rui,Zhang, Shenghai,Lyu, Jitong,Lu, Fang,Yue, Xuanfeng,Lv, Jiagen
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supporting information
p. 8078 - 8081
(2015/05/20)
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- Bronsted base-assisted boronic acid catalysis for the dehydrative intramolecular condensation of dicarboxylic acids
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Bronsted base-assisted boronic acid catalysis for the dehydrative self-condensation of carboxylic acids is described. Arylboronic acid bearing bulky (N,N-dialkylamino)methyl groups at the 2,6-positions can catalyze the intramolecular dehydrative condensation of di-and tetracarboxylic acids. This is the first successful method for the catalytic dehydrative self-condensation of carboxylic acids.(Figure Presented)
- Sakakura, Akira,Ohkubo, Takuro,Yamashita, Risa,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 892 - 895
(2011/05/02)
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- METHOD FOR PRODUCING CARBOXYLIC ANHYDRIDE AND ARYLBORONIC ACID COMPOUND
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When phthalic acid is heated in heptane under azeotropic reflux conditions in the presence of a catalytic amount of an arylboronic acid compound (such as 2,6-(diisopropylaminomethyl)phenylboronic acid or 2,6-bis(diisopropylaminomethyl)phenylboronic acid), phthalic anhydride is obtained in high yield.
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Page/Page column 10-11
(2012/01/13)
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- An inexpensive and efficient synthetic method for the preparation of pyromellitic dianhydride promoted by ionic liquid
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In this article, pyromellitic dianhydride could be successfully obtained in 76.7% total yield by an aerobic oxidation of 1,4-bis(chloromethyl)-2,5- dimethylbenzene or 1,5-bis(chloromethyl)-2,4- dimethylbenzene catalyzed by VO(acac)2/Cu(2-Eth)2/DABCO in [hmim]OTf and a subsequent dehydration of pyromellitic acid upon heating with acetic anhydride. The starting materials including 1,2-bis(chloromethyl)-4,5-dimethylbenzene were prepared by dichloromethylation of their corresponding xylene catalyzed by [C12mim]Br in aqueous media. ARKAT USA, Inc.
- Hu, Yu Lin,Lu, Ming,Liu, Xiao Bin,Zhang, Sheng Bin,Ji, Zhan Hui,Lu, Ting Ting
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experimental part
p. 63 - 74
(2010/10/19)
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- Esters of pyromellitic acid. Part I. Esters of achiral alcohols: Regioselective synthesis of partial and mixed pyromellitate esters, mechanism of transesterification in the quantitative esterification of the pyromellitate system using orthoformate esters, and a facile synthesis of the ortho pyromellitate diester substitution pattern
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(Chemical Equation Presented) Mild conditions and reversible anhydride formation allow a relative differentiation to be made of the four equivalent carbonyl groups of pyromellitic dianhydride (PMDA, benzene-1,2,4,5- tetracarboxylic dianhydride) in esterification, leading to regioselective methods to generate a wide range of partially or totally esterified products or products bearing differing esterifying groups at the different positions. Pyromellitate monoester anhydrides form efficiently in dichloromethane/ triethylamine from 1 equiv of the alcohol. Under the same conditions, two different alcohols can be made to react sequentially. With 2 equiv of an alcohol, the usual mixture of meta and para diesters is obtained, separated by crystallization from HOAc. Meta and para dibenzyl pyromellitates served as regiospecific sources of other diesters, by further esterification followed by hydrogenolysis. Refluxing orthoformate triesters were found to effect quantitative esterification of the pyromellitate system under autocatalytic conditions; minor ester exchange with pre-existing esters (0-5% of total product) was ascribed to reversible anhydride formation. For general esterification with alcohols, partial ester acid chlorides were obtained using oxalyl chloride. Pyromellitate triesters afforded the ortho diester anhydrides upon distillation, thereby providing facile entry into the mostly novel ortho substitution pattern in this system. The requisite triesters were prepared by selective saponification or by the prior incorporation of one benzyl ester substituent, which could be removed by catalytic hydrogenolysis. The various benzyl esters of pyromellitates hydrogenolyzed smoothly to release the carboxylic acid groups without disturbance of pyromellitate aromaticity.
- Paine III, John B.
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p. 4929 - 4939
(2008/12/21)
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- Production method of highly pure pyromellitic dianhydride
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A method of producing pyromellitic dianhydride. The method includes a step of heating a crude pyromellitic acid in the absence of acetic anhydride to convert a part of pyromellitic acid to pyromellitic anhydride, and a subsequent step of heating the resultant mixture in the presence of acetic anhydride to complete the anhydrization of pyromellitic acid. The pyromellitic dianhydride by the method contains little pyromellitic monoanhydride and other monoanhydrides derived from impurities and is less discolored. The pyromellitic dianhydride has particle properties not causing plugging, etc. during its transportation, storage and use.
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Page/Page column 8-10
(2008/06/13)
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- PROCESS FOR OXIDATION OF ORGANIC COMPOUNDS
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A method oxidizes an organic compound with oxygen in the presence of a catalyst, in which the catalyst contains a N-hydroxy- or N-(substituted oxy)-imide compound derivable from at least one selected from a target product, a reaction intermediate, and a reaction byproduct, and the catalyst is produced from at least one component selected from the target product, reaction intermediate, and reaction byproduct each formed as a result of the reaction and is used in the oxidation reaction so as to make up for a loss of the catalyst due to denaturation in the reaction. The method can easily and inexpensively make up for a loss of the catalyst denaturated in the course of reaction.
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Page/Page column 17
(2008/06/13)
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- Production method of pyromellitic acid and pyromellitic anhydride
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In a method of producing pyromellitic acid by liquid-phase oxidizing 2,4,5-trimethylbenzaldehyde in a water solvent with molecular oxygen, a recrystallization mother liquor separated in a recrystallization step is recycled to the oxidation step after a part of the water solvent is removed. With this method, the loss of pyromellitic acid and the oxidation catalyst can be minimized and the burden of discharging the waste water is reduced without lowering the efficiency of the liquid-phase oxidation reaction.
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Page column 4
(2008/06/13)
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- Process for producing pyromellitic anhydride
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The present invention has for its object to provide a production method of pyromellitic anhydride of high purity in good yield at low cost by catalytic gas-phase oxidation of a 2,4,5-trialkylbenzaldehyde with the aid of a suitable catalyst system. The present invention relates to a production method of pyromellitic anhydride comprising a step for catalytic gas-phase oxidation of a 2,4,5-trialkylbenzaldehyde with a molecular oxygen-containing gas in which said step for catalytic gas-phase oxidation is carried out in the presence of a catalyst such that a specific surface area of the catalytic active component thereof is not greater than 50 m2/g or in the presence of a catalyst containing vanadium as well as molybdenum and/or tungsten as a catalytic active component.
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- Process for producing refined pyromellitic acid and refined pyromellitic anhydride
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A process for refined pyromellitic anhydride which comprises dissolving crude pyromellitic acid or crude pyromellitic anhydride in water, then cooling an aqueous solution thus obtained to perform crystallization as pyromellitic acid, then separating a crystal thus obtained from water, then anhydrating the crystal of pyromellitic acid thus separated with heating to produce pyromellitic anhydride, then vaporizing pyromellitic anhydride thus produced, cooling vapor of pyromellitic anhydride thus obtained, and thereby, recovering a refined crystal of pyromellitic anhydride.
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- Catalyst for gas phase partial oxidation
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This invention relates to a method for producing a partially oxidized organic compound, e.g., an unsaturated aldehyde/carboxylic acid having three or more carbon atoms, or an organic acid anhydride/nitrile compound having four or more carbon atoms. This method requires a catalyst prepared by treating a carrier in such a manner that water used in the treatment achieves specific resistance.
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Example II-4
(2010/01/30)
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- Process for the preparation of pyromellitic dianhydride
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The present invention relates to a process for preparing pyromellitic dianhydride via an oxidation in gas phase under normal pressure. The process is characterized in that a catalyst system is used, which catalyst system comprises a catalyst which is a mixture of vanadium and tungsten oxides; a catalyst support comprising rutile and at least one material selected from the group consisting of tungsten carbide, silicon carbide and a mixture thereof; and a cocatalyst comprising oxides of manganese, antimony, bismuth, phosphorus, copper, aluminum, titanium or a mixture thereof, an oxide of an element of the VIIIB group of the periodic table, and an oxide of an alkali metal and/or alkaline earth metal. In this process, pyromellitic dianhydride is produced from a feedstream containing 1,2,4,5-tetraalkylbenzene in a gas flow rate of 4,000 DIFFERENCE 12,000 hr-1 via a selective oxidation at 300 DIFFERENCE 450 DEG C. in the presence of air which acts as an oxidant.
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- Compounds, polymers, resin compositions and nonlinear optical devices
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The present invention provides, as heteroaromatic compounds made functional so as to be used for nonlinear optical materials, compounds represented by the following general formula (1), and also provides polymers obtained from these and nonlinear optical parts comprising such polymers. In the formula, Ar1 and Ar2 each represents a divalent aromatic group; R1, R2 and R3 each represents an atom or a group independently selected from a hydrogen atom or an alkyl group and an aromatic group; X1 represents a monovalent organic group; n represents an integer of 2 to 12; and Z1 and Z2 each represents a group independently selected from electron attractive functional groups.
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- Process for the preparation of pyromellitic anhydride
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A process for the efficient production of high purity pyromellitic anhydride from 1-ethyl-2,4,5-triisopropylbenzene as a starting material.
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- N-cyanoimides
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Polyfunctional N-cyanoimides and their precursors and derivatives are disclosed along with methods for their preparation and interconversion. Also disclosed are curable compositions comprising the N-cyanoimides or poly(amide-cyanoamides) and reactive diluents as well as novel dianhydrides, polyimides, and poly(amide-cyanoamides) and methods for making them.
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- Process for producing pyromellitic dianhydride
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Pyromellitic dianhydride, useful as raw material for the manufacture of polyimides, is prepared in high yield and purity by the reaction of benzene derivatives such as ethylbenzene, diethylbenzenes, and triethylbenzenes with an ethylating agent in the presence of a Friedel-Crafts catalyst, the separation of tetraethylbenzenes from the reaction products by distillation, the separation of 1,2,4,5-tetraethylbenzene from other tetraethyl benzenes by differential centrifugal precipitation at -10 to -30 degrees Celsius, and the catalytic vapor-phase oxidation of tetraethyl benzenes, using a catalyst containing vanadium pentoxide and titanium dioxide.
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- Diamines and photosensitive polyimides made therefrom
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Disclosed is an aromatic diamine having the general formula where A is a group containing at least one aromatic ring, each Y is independently selected from or -OR, R is a group containing at least one olefinically unsaturated group, R' is hydrogen, alkyl to C25, aryl, or R, n is 1 to 4, and the number of olefinic groups in Y is at least 3 when each Y is and otherwise is at least 2. Photosensitive polyamic acids and polyimides can be prepared from the aromatic diamines which can be crosslinked with light to a mask to form patterns on a substrate.
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- Polymers prepared from 4,4'-bis-(2-(amino (halo) phenoxyphenyl) hexafluoroisopropyl) diphenyl ether
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The application relates to fluorine-containing polyimides, polyamide-acids/esters, polyamides, addition polyimides and imide oligomers which exhibit low melting points, better solubilities, low dielectric constants, superior thermal and thermal oxidative stability, and improved processing characteristics. The products of this application are characterized by the fact that they are derived from 4,4'-bis[2-(amino(halo)phenoxyphenyl)hexafluoroisopropyl]diphenyl ether.
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- Bis-(maleamic acid) derivatives of triamines
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The compositions described herein comprise polyimides having bis-maleimide terminal groups and having the formula: STR1 wherein Q is a trivalent aromatic radical, Ar is a divalent aromatic radical, Ar" is a tetravalent aromatic radical and n has a value of 0-20. Derivatives may be made of these compounds by homopolymerization, copolymerization with other copolymerizable materials and by reaction with Diels-Alder reactable materials.
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- Dynamic Spectral Shifts of Molecular Anions in Organic Glasses
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Time-dependent spectra of the radical anions of pyromellitic dianhydride and p-dinitrobenzene have been observed after formation by pulse radiolysis in frozen 2-methyltetrahydrofuran and triacetin glasses.At temperatures near the glass transition, the spectra shift toward the blue over the entire observed time range (100 ns - 100 s), while at temperatures well below the glass transition, the spectral shifts can be stopped or greatly slowed.The magnitudes of the shifts are not large (typically ca. 10 nm), but because they are larger than the vibrational line widths, dramatic kinetics may be observed: the absorbance grows or decays by more than a factor of five at some wavelengths.The observations are consistent with a solvent molecule reorientation mechanism for spectral shifts of molecular ions in low-temperature organic glasses.
- Huddleston, R. Kurt,Miller, John R.
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p. 2410 - 2415
(2007/10/02)
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- Polyimide derivatives having terminal unsaturated amides
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Novel compositions comprising unsaturated polyimide-polyamides and processes for their preparation are disclosed herein. These new compositions are primarily derivatives of anhydride-terminated aromatic polyimides from which they are prepared by amidation to provide unsaturated amide groups having terminal --CH=CH2 groups. These new compositions are more tractable than the original anhydride-terminated polyimides and can be converted at appropriate lower temperatures to crosslinked, insoluble, infusible polymers without by-product formation thereby extending greatly the applications for which the aromatic polyimides can be employed. Also included are monomeric compounds containing unsaturated amide groups derived from monomeric tetracarboxylic dianhydrides. These are particularly useful as crosslinking agents.
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- Polyimide derivatives having unsaturated terminal amic acid groups
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Novel compositions comprising unsaturated polyhemi-amic acid compositions and processes for their preparation are disclosed herein. These new compositions are primarily derivatives of anhydride-terminated aromatic polyimides from which they are prepared by amidation to provide unsaturated amide groups having terminal --CH=CH2 groups as hemi-amic acid groups or their derivatives. These new compositions are more tractable than the original anhydride-terminated polyimides and can be converted at appropriate lower temperatures to crosslinked, insoluble, infusible polymers without by-product formation thereby extending greatly the applications for which the aromatic polyimides can be employed. Also included are monomeric compounds containing unsaturated amide groups derived from monomeric tetracarboxylic dianhydrides. These are particularly useful as crosslinking agents.
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- Optical brightening agents of naphthalimide derivatives
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A naphthalimide derivative having the formula STR1 wherein R is an alkyl, or cycloalkyl, an aralkyl, a haloalkyl, an alkoxyalkyl, a hydroxyalkyl, an N,N-dialkylaminoalkyl, an unsubstituted or halogen-, alkyl-, alkoxy- or hydroxy-substituted aryl, or an ammoniumalkyl; X is a group of the formula, STR2 wherein A is STR3 or an unsubstituted or halogen-substituted arylene, or a group of the formula, STR4 wherein R1 is hydrogen, an alkyl, phenyl, a hydroxyalkyl, or an alkoxyalkyl; Y is --CO--, --COO--, --CONR3 -- (where R3 is hydrogen or an alkyl), or --SO2 --; R2 is hydrogen, an alkyl, a cycloalkyl, an aralkyl, a haloalkyl, an alkyl- or aryl-substituted amino-alkyl, an unsubstituted or halogen-, alkyl-, alkoxy-, hydroxy-, amino- or alkylamino-substituted aryl, a group of the formula, STR5 (where R, R1 and Y are as defined above and R4 is a bivalent group), or a group of the formula, (where R5 is direct linkage or a bivalent group; Q+ is a substituted ammonium, a cycloammonium or a hydrazinium; and α- is an anion), Which is useful for optically brightening an organic polymer material.
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