Mitsui Petrochemical Industries, Ltd.

Mitsui Chemicals, Inc.

Masahiro Kondo

Hiroaki Nakagawa

Michio Tanaka

Noriake Ohishi

Sanehiro Yamamoto

Yoshito Kurano

Naoya Sakamoto

Masato Kawamura

Hajime Ooyoshi

Mask protective device

In a method of producing a keto acid having the general formula ##STR1## wherein R.sup.1 and R.sup.2 independently represent an alkyl of 1-6 carbons or a cycloalkyl of 4-8 carbons, by reacting an m-aminophenol having the general formula ##STR2## wherein R.sup.1 and R.sup.2 are the same as above, with phthalic anhydride, in an organic solvent, the improvement comprising effecting the reaction in an amount of the organic solvent which is insufficient to dissolve the keto acid produced in the reaction, so that at least a portion of the resultant keto acid crystallizes out of the solvent and allowing the reaction to proceed in a heterogeneous system.

Method of producing keto acids

N-alkyl amino phenols, such as N-ethyl-m-amino phenol are produced in high yield and with high purity by reacting a divalent phenol, such as resorcinol, with an alkylamine, such as ethylamine, in the absence of catalyst and solvent, at a temperature of 120.degree.-210.degree. C. under elevated pressure in an inert gas atmosphere. In a first embodiment, the resulting reaction mixture is acidified to convert the N-alkylaminophenol to its water soluble salt and the resulting aqueous layer is separated from the oily layer. The aqueous layer is rendered alkaline to liberate N-alkylaminophenol as an oily layer. The N-alkyl-aminophenol oily layer is then separated from the aqueous layer and distilled. In an alternative embodiment, the reaction mixture resulting from the reaction between the divalent phenol and alkylamine is combined with an aqueous solution of an alkali to convert unreacted phenol to its water soluble salt while the product N-alkylaminophenol remains in an oily phase which is separated from the aqueous phase. An organic solvent is used as an extractant. The recovered N-alkylaminophenol organic solution is then distilled to recover N-alkylaminophenol. Purities of the recovered N-alkylaminophenol in excess of 95% can be achieved.

Method of producing N-alkylaminophenols

Disclosed is a process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming menthod. The cellulose ester film prepared according to this process is excellent in the thickness uniformity and free of color nonuniformity or streaks and has good optical properties.

Process for preparation of cellulose nitrate films

Disclosed is a process for the preparation of cellulose ester films, which comprises dissolving a cellulose ester in an organic solvent, coating the solution on a substrate under rotation and peeling the film formed on the substrate from the substrate, wherein a second organic solvent having a compatibility with the organic solvent and being a poor solvent to the cellulose ester is added to the organic solvent solution of the cellulose ester to precipitate a cellulose ester having a high molecular weight in the cellulose ester, the cellulose ester having a high molecular weight is separated from the solution, and the remaining cellulose ester solution is formed into a cellulose ester film by the rotational film-forming method. The cellulose ester film prepared according to this process is excellent in the thickness uniformity and free of color nonuniformity or streaks and has good optical properties.

Process for preparation of cellulose ester films

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Yamaguchi, Japan

Masahiro Kondo