摘要:
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.
摘要:
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.
摘要:
A process for producing a polycarboxylic acid which comprises performing liquid phase oxidation of polyalkyl-substituted aromatic aldehyde and/or oxide derivative of polyalkyl-substituted aromatic aldehyde as raw material for oxidation with molecular oxygen at two stages in water solvent in the presence of a catalyst comprising bromine or both bromine and a heavy metal(s) at a temperature of 180 to 280 ° C., thereby producing trimellitic acid or pyromellitic acid, wherein said liquid phase oxidation is performed in a continuous operation at the first stage and in a continuous operation or in a batch operation at the second stage and a total amount of bromine in said catalyst is divided to add separately at each the first stage and the second stage.
摘要:
A process for the production of a trimellitic acid by oxidizing dialkyl aromatic aldehyde and/or its oxide derivative in a liquid phase, the oxidation being carried out in a lower aliphatic carboxylic acid solvent having a water content of 5 to 70% by weight in the presence of a catalyst containing a heavy metal and bromine or being carried out in a solvent containing a lower aliphatic carboxylic acid in the presence of a bromine-manganese catalyst system containing zirconium and/or cerium, and a process for the production of high-quality trimellitic acid anhydride from the trimellitic acid.
摘要:
A process for producing 2,6-naphthalenedicarboxylic acid comprising oxidizing 2,6-dimethylnaphthalene with a gas containing oxygen in a solvent comprising a lower aliphatic carboxylic acid in the presence of a catalyst comprising cobalt, manganese, and bromine, wherein the total amount of cobalt and manganese in the catalyst is 50 to 300 mg atom per 1 g mol of 2,6-dimethylnaphthalene, a ratio by g atom of manganese to cobalt in the catalyst is 20:1 to 4:1, and the oxidation is conducted at a temperature of 200 to 250.degree. C.; and a process as described above, wherein a mother liquor which is obtained from a slurry of a product of the oxidation via a step of solid-liquid separation is recyled to a step of oxidation after heat treatment at a temperature of 150.degree. C. or higher. In accordance with the processes, accumulation of substances which affect the oxidation adversely is prevented. Moreover, a large fraction of a mother liquor of oxidation can be recycled without decrease in the yield of the reaction, and the catalyst components and the solvent components in the mother liquor of oxidation can be utilized efficiently.
摘要:
A process for producing pyromellitic acid which comprises oxidizing 2,4,5-trimethylbenzaldehyde and/or its oxidized derivative in the presence of a catalyst containing iron, manganese and bromine, or additionally containing zirconium or cerium continuously or semi-continuously using aqueous acetic acid solvent and 0.05-2% by weight of bromide ion. The catalyst used in the present invention has high activity, and the catalyst solution has low corrosive because the reaction is performed at low bromide concentration by using a solvent of aqueous acetic acid. So pyromellitic acid is produced industrially advantageously in high yield continuously or semi-continuously which has been a major difficulty up to now.
摘要:
A process for producing purified .epsilon.-caprolactone from an .epsilon.-caprolactone-containing reaction product produced by the oxidation of cyclohexanone comprising subjecting the .epsilon.-caprolactone-containing reaction product to an alkali-treatment in the presence of an inert gas atmosphere or to a heat treatment in the presence of an inert gas atmosphere or to a combined alkali-treatment and heat treatment, and distilling the treated reaction product.
摘要:
What is disclosed is a process for producing &egr;-caprolactone which comprises removing impurities by distillation from a reaction mixture obtained by co-oxidation of cyclohexanone and aldehyde, wherein &egr;-caprolactone separated from a purifying column is contacted with oxygen containing gas in the presence of cobalt. High boiling point components are removed to give an acid value of lower than 0.15 mgKOH/g. Thereby, a high quality &egr;-caprolactone providing improved polymer appearance is produced advantageously on an industrial scale without repeated purifying distillations or without using expensive stabilizer or adsorbent for the improvement of color.
摘要:
An adhesive composition, an optical member, a surface protective film, and an adhesive sheet, the adhesive composition including 100 parts by weight of a (meth)acrylic copolymer having a weight average molecular weight of about 100,000 to about 2,000,000 g/mol; about 0.01 to about 5 parts by weight of a peroxide crosslinking agent; and about 0.001 to about 5 parts by weight of a carbodiimide.
摘要:
This invention provides a fluid control device capable of making compact a fluid control device in which a valve and a limit switch are combined. A valve 6 includes a piston 26 as a moving member which includes a protruding portion protruding from an opening of a casing 21, and which linearly moves according to opening and closing of the valve 6 so as to abut against a limit switch 7. The limit switch 7 is made to face the piston 26 and is attached via a limit switch positioning unit 8 so as to be adjustable about its position. The limit switch positioning unit 8 includes a first bolt 42 fixed to a body 2, a second bolt 43 fixed to the limit switch 7, and a connection screw 44 which connects both the bolts 42, 43. The first bolt 42 and the second bolt 43 have different pitches from each other.