Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2002-11-22
2004-02-24
Rotman, Alan L. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
Reexamination Certificate
active
06696595
ABSTRACT:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/JP01/04036 which has an International filing date of May 15, 2001, which designated the United States of America.
TECHNICAL FIELD
The present invention relates to a method for producing a high purity alkyladamantyl ester by distilling and purifying a crude alkyladamantyl ester containing impurities.
BACKGROUND ART
Heretofore, when a solution to be distilled which contains a target compound also contains materials which promote decomposition of the target compound despite the fact that the target compound is a compound which is easily decomposed under influence of heat, a catalyst or the like, the target compound is easily decomposed during distillation. Therefore, it is difficult to obtain the target compound at a high purity or a high yield by purification by distillation. In general, even if a very small amount of materials which exhibit a decomposition promoting action is contained, it is very difficult to identify and remove the materials to such an amount that does not adversely affect the target compound because they cause decomposition of the target compound at the time of heating. In such a case, a purification method other than distillation must be used so as to purify a easily decomposable target compound with good reproducibility and at a high purity.
Meanwhile, demand for products of higher purity has been increasing every year. In particular, a reduction in metal components of a product used in a semiconductor production process is strongly demanded. As a purification method which can remove such metal components efficiently, purification by distillation is suitable.
In recent years, it has been reported that polymers obtained from alkyladamantyl esters having polymerizable groups have high dry etching resistance in a semiconductor production process (refer to JP-A 5-265212), and a possibility of their use as resist materials for semiconductors has been receiving attention. When these alkyladamantyl esters are used as resist materials for semiconductors, high purity alkyladamantyl esters having reduced metal components are required.
It is known that the alkyladamantyl ester can be produced by reacting 2-alkyl-2-adamantanol or 2-alkylideneadamantane which is obtained via 2-adamantanone from adamantane as a starting material or 2-adamantanone with an organometallic reagent such as methyl magnesium bromide so as to obtain a metal alkoxide and reacting a carboxylic acid derivative such as a carboxylic acid ester, a carboxylic anhydride or a carboxylic acid halide or a carboxylic acid with the obtained metal alkoxide.
In general, the alkyladamantyl ester is easily decomposed when stimulated by acid, heat or the like. For example, it is known that the alkyladamantyl ester is decomposed into a carboxylic acid or the like when heated in the presence of a catalytic amount of acid. By use of such a characteristic, the alkyladamantyl ester is used as a raw material for a chemically amplified resist in a semiconductor production process. Therefore, to purify the alkyladamantyl ester by distillation, it is commonly practiced to wash the alkyladamantyl ester with an alkali solution such as a sodium hydroxide solution as a pretreatment so as to remove acid components.
However, when a crude alkyladamantyl ester which has been subjected to a conventional pretreatment such as washing with an alkali solution so as to remove acid components is distilled by a commonly used method, the alkyladamantyl ester is decomposed during distillation for some reason, thereby producing a decomposition product such as a carboxylic acid or 2-alkylideneadamantane. Thus, a high purity alkyladamantyl ester has not been able to be obtained at a good yield.
Further, it has been found that a crude alkyladamantyl ester or a distilled and purified alkyladamantyl ester is decomposed during storage for some reason, thereby causing such a problem as coloration. In addition, it has also been found that an alkyladamantyl ester having a polymerizable group has a problem that when the alkyladamantyl ester is decomposed during storage to have coloration, a molecular weight does not increase even if it is polymerized.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a method for producing a high purity alkyladamantyl ester by applying an efficient purification method to a crude alkyladamantyl ester for which an efficient distillation and purification method has not been known.
The present inventor has made intensive studies so as to solve the above problems. As a result, he has found that a crude alkyladamantyl ester can be purified efficiently by distilling the alkyladamantyl ester in the presence of a heterocyclic compound and/or a basic compound and that the above compounds also have an effect of improving storage stability of the alkyladamantyl ester. The present inventor has completed the present invention by these findings.
That is, the present invention is a method for producing a high purity alkyladamantyl ester which comprises the steps of esterifying an adamantane compound having an —OH group, —OM group or ═R group (wherein M is an alkali metal atom or MgX (wherein X represents a halogen atom), and R is a divalent aliphatic hydrocarbon group) and distilling a crude alkyladamantyl ester obtained to form a high purity alkyladamantyl ester, wherein the distillation is carried out in the presence of a heterocyclic compound and/or a basic compound.
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, a crude alkyladamantyl ester to be distilled is obtained by esterification of an adamantane compound having an —OH group, —OM group or ═R group (wherein M is an alkali metal atom or MgX (wherein X represents a halogen atom), and R is a divalent aliphatic hydrocarbon group). The crude alkyladamantyl ester obtained by such a process contains an impurity which can decompose the alkyladamantyl ester. Although the impurity has not heretofore been identified yet, the present inventors assume that it may be a compound which decomposes under distillation conditions and produces acid.
In the —OH group, —OM group or ═R group (wherein M is an alkali metal atom or MgX (wherein X represents a halogen atom), and R is a divalent aliphatic hydrocarbon group) in the adamantane compound which is a raw material of the crude alkyladamantyl ester, the alkali metal atom represented by M is a potassium atom, a sodium atom or the like, and the halogen atom represented by X is a chlorine atom, a bromine atom, an iodine atom or the like. Further, the divalent aliphatic hydrocarbon group represented by R is exemplified by a divalent group having 1 to 4 carbon atoms such as a methylidene group, an ethylidene group, a propylidene group, an isopropylidene group and the like.
Illustrative examples of the adamantane compound having the —OH group, —OM group or ═R group include 2-alkyl-2-adamantanol (wherein the alkyl group has 1 to 6 carbon atoms) having an —OH group, 2-alkylideneadamantane (wherein the alkylidene group has 1 to 4 carbon atoms) having an ═R group, and a compound represented by the following formula (1)
(wherein R
1
is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and M is an alkali metal atom or MgX (wherein X represents a halogen atom)).
Illustrative examples of a specific production method of the crude alkyladamantyl ester include a method comprising the steps of alkylating 2-adamantanone with a Grignard reagent such as an alkyl magnesium halide or an organometallic reagent such as alkyl lithium so as to obtain an adamantane compound having an —OM group and then esterifying the adamantane compound with a carboxylic acid halide; a method comprising the steps of alkylating 2-adamantanone with an organometallic reagent so as to obtain 2-alkyl-2-admantanol and then esterifying the compound with a carboxylic acid halide, carboxylic anhydride or carboxylic acid ester; and a method comprising the steps of alkylating 2-adamantanone with an organometall
Hirota Yoshihiro
Kobayakawa Takashi
Yamaguchi Masao
Yamamoto Hiromasa
Reyes Hector M
Tokuyama Corporation
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