- A 1, 2, 3, 4 - cyclopentane tetracarboxylic dianhydride of the preparation method (by machine translation)
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The invention discloses a 1, 2, 3, 4 - cyclopentane tetracarboxylic dianhydride of the preparation method, the invention belongs to the field of fine chemicals preparation method. The main technical proposal is to maleic anhydride and the cyclopentadiene as the starting material, the low temperature by 1, 4 - addition reaction intermediate of synthesis of 5 - norbornene - 2, 3 - dicarboxylic acid anhydride; through the ozone oxidation, hydrolysis, hydrogen peroxide oxidation reaction to obtain the cyclopentane tetracarboxylic acid; finally to acetic anhydride as the dehydrating agent, the dehydration ring-closure of the synthesized target product 1, 2, 3, 4 - cyclopentane tetracarboxylic dianhydride. The proposal to the traditional process, mild reaction conditions, the product has high purity, high yield, pollution-free and the like, and is suitable for large-scale industrial production. (by machine translation)
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Page/Page column 3-6
(2019/05/04)
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- CAGE-SHAPED CYCLOPENTANOIC DIANHYDRIDE, METHOD FOR PRODUCTION THEREOF, AND POLYIMIDE
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A cage 1,2,3,4-cyclopentanetetracarboxylic acid (1,3:2,4)-dianhydride compound represented by formula [1], and a polyimide obtained by condensing the compound with a diamine. With the compound, it is possible to provide a polyimide which shows no absorption in the ultraviolet region and is highly transparent to light, has high insulating properties, has improved heat resistance and processability, and has excellent solubility in organic solvents. (In formula [1], R1 and R2 each independently represents a hydrogen atom, a halogen atom, or a C1-10 alkyl.)
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Page/Page column
(2014/05/07)
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- Optically active phenoxypropionic esters
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Optically active compounds of the formula I STR1 where R is C1 -C12 -alkyl or -perfluoroalkyl in which one or two non-adjacent CH2 or CF2 groups can also be replaced by --O-- and/or --CO-- and/or --CO--O-- and/or --CH=CH-- and/or --CH-halogen-- and/or --CHCN-- and/or --0--CO--CH-halogen-- and/or --O--CO--CHCN--, or is C1 -C12 -alkyl which can have a terminal chemically reactive group and in which a CH2 group can be replaced by --O--, A1 and A2 are each, independently of one another, 1,4-phenylene which is unsubstituted or substituted by one or two F and/or Cl and/or Br atoms and/or CH3 groups and/or CN groups and in which one or two CH groups can also be replaced by N, 1,4-cyclohexylene in which one or two non-adjacent CH2 groups can also be replaced by --O-- and/or --S--, 1,4-piperidinediyl, 1,4-bicyclo[2.2.2]octylene, 2,6-naphthalenediyl, decahydro-2,6-naphthalenediyl or 1,2,3,4-tetrahydro-2,6-naphthalenediyl, A3 is unsubstituted or substituted phenyl, Z is --CO--O--, --O--CO--, --CH2 CH2 --, --OCH2 --, --CH2 O--, --C C-- or a single bond and m is 0, 1, 2 or 3.
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- Process for, respectively, the production and purification of dicarboxylic and polycarboxylic acid anhydrides
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A method of preparation and/or purification of acid anhydrides is disclosed. Dicarboxylic or polycarboxylic acids contained in the anhydrides to be treated, are dehydrated in an organic solvent in the presence of activated carbon.
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