Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
1999-11-18
2001-03-20
Geist, Gary (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
Reexamination Certificate
active
06204409
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel urethane compound. More particularly, the present invention relates to a novel biscarbamate compound having a norbornane skeleton.
Further, the present invention relates to a method for producing a polycyclic aliphatic diisocyanate using the above-described urethane compound, and more particularly, a method for producing a polycyclic aliphatic diisocyanate having a norbornane skeleton.
BACKGROUND ART
Conventionally, aromatic urethane and (cyclic)aliphatic urethane are known as urethane compounds, and typical examples thereof include methyl carbamate, ethyl carbamate, diethyltolylene-2,4-dicarbamate, dimethylmetaxylylene dicarbamate, 1,4-bis(methoxycarbonylaminomethyl)cyclohexane, di-n-butylhexamethylene-1,6-dicarbamate, 5-(butoxycarbonylamino)-1-(butoxycarbonylaminomethyl)-1,3,3-trimethylcyclohexane and the like, and they are utilized in various uses.
Further, though developing agents for thermosensible paper, powder paints (e.g., electrodeposition paint and the like), spectacle lenses and the like obtained by using as a raw material a diisocyanate compound having a norbornane skeleton have excellent properties, as their production method, there is only known a method in which carbamoyl obtained by reaction of a diamine compound having a norbornane skeleton with phosgene is thermally-decomposed. However, phosgene has strong toxicity, and in addition, phosgene and hydrochloric acid by-produced in large amount require complicated treatment and an apparatus for the treatment should have corrosion. resistance leading to complicated constitution.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a novel urethane compound which can be utilized as a raw material of block isocyanate, diisocyanate, developing agent for thermosensible paper, powder paint and the like. Another object of the present invention is to provide a production method thereof, and a method for producing a cyclic aliphatic diisocanate by using a biscarbamate compound having a norbornane skeleton which is a novel urethane compound, without using phosgene.
The present inventors have widely studied for attaining the above-described object, and as a result, found that a urethane compound having specific structure is novel and is a useful compound for the above-described uses, thus completed the present invention.
Namely, an object of the present invention is to provide a novel urethane compound represented by the following general formula (1):
(wherein, R1 and R2 may be the same or different and represent a straight or branched alkyl group, (substituted) cycloalkyl group or (substituted) aryl group.).
The present inventors have found that a diisocyanate compound having a norbornane skeleton can be produced by using a biscarbamate compound having a norbornane skeleton without using phosgene, thus completed the present invention.
Namely, the present invention provides the following subjects (1), (2) and (3) to (10).
(1) A biscarbamate represented by the following general formula (1):
(wherein, R1 and R2 may be the same or different and represent a straight or branched alkyl group, (substituted) cycloalkyl group or (substituted) aryl group.).
(2) A novel urethane compound comprising a biscarbamate described in (1) above.
(3) A method for producing a biscarbamate compound wherein a biscarbamate compound described in (1) above is produced from urea or carbonate.
(4) A method for producing a biscarbamate compound wherein in producing a biscarbamate compound described in (1) above using a diamine compound, urea and aliphatic alcohol, the production is conducted while removing out of the reaction system ammonia by-produced in reaction of the diamine compound, urea and aliphatic alcohol.
(5) The method for producing a biscarbamate compound according to (4) described above, wherein vapor phase is drawn out from a reaction vessel and is condensed, then, a condensed component is recycled to the reaction vessel, and a non-condensed component is also recycled to the reaction vessel after removal of ammonia therefrom.
(6) The method for producing a biscarbamate compound according to (4) described above, wherein the production is conducted while maintaining the ammonia concentration in the reaction solution at 1 wt. % or less.
(7) A method for producing a polycyclic aliphatic diisocyanate wherein a cyclic diisocyanate is produced by thermally-decomposing a biscarbamate described in (1) above.
(8) The method for producing a polycyclic aliphatic diisocyanate according to (7) described above, wherein the thermal-decomposition is conducted at a total content of compounds having a norbornane ring in the thermal-decomposition reaction solution of 60 wt. % or more and a content of a biscarbamate in the thermal-decomposition reaction solution of 50 wt. % or less.
(9) The method for producing a polycyclic aliphatic diisocyanate according to (7) described above, wherein a biscarbamate is thermally-decomposed, the thermally-decomposed product is separated into a mixture in which the total content of compounds having a norbornane ring is 60 wt. % or more and the content of a biscarbamate is 50 wt. % or less, and other components, and the mixture is thermally-decomposed to produce a polycyclic aliphatic diisocyanate.
(10) The method for producing a polycyclic aliphatic diisocyanate according to (7) described above, wherein the thermal-decomposition reaction is conducted at least at two stages, and thermal-decomposition of the latter stage is conducted at a temperature at least 5° C. higher than that of thermal-decomposition of the former stage.
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Aso Shinji
Noguchi Takeshi
Ogawa Shinji
Burns Doane Swecker & Mathis L.L.P.
Geist Gary
Mitsui Chemicals Inc.
Oh Taylor V.
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