Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-12-19
2002-11-26
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C502S159000, C568S727000
Reexamination Certificate
active
06486364
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to amine modified acidic resin catalysts and their use in the reaction of hydroxyaromatic compounds with aldehydes and ketones in the presence of a thiol promoter to afford bisphenols, such as bisphenol A (BPA).
Bisphenols, as exemplified by BPA, are widely employed in the manufacture of polymeric materials and are typically prepared by condensation of a hydroxyaromatic compound with an aldehyde or ketone in the presence of an acidic catalyst. Bisphenol A is the principal monomer used in the manufacture of bisphenol A polycarbonate, a commercial engineering thermoplastic material. The manufacture of bisphenol A from acetone and phenol is practiced globally on a large scale with hundreds of millions of pounds of BPA produced annually. Typically, phenol is reacted with acetone in the presence of an acidic catalyst and a thiol promoter. The thiol promoter acts to improve the rate and selectivity of BPA formation in the acid catalyzed condensation of phenol with acetone. Many different combinations of acidic catalysts and thiol promoters have been investigated and some thiol promoters such as 3-mercaptopropionic acid have been employed in the commercial scale production of BPA. Notwithstanding earlier research efforts and their attendant impressive process improvements in the manufacture of bisphenols, such as bisphenol A, there is a continuing need to improve further both the rate and selectivity of bisphenol formation in the acid catalyzed condensation of hydroxyaromatic compounds with aldehydes or ketones.
BRIEF SUMMARY OF THE INVENTION
In one aspect the present invention relates to a method for making a bisphenol, said method comprising contacting a mixture comprising a hydroxyaromatic compound and a ketone or an aldehyde with an amine modified acidic resin catalyst at a temperature in a range between about 25° C. and about 95° C. in the presence of a thiol promoter. In a further aspect, the present invention relates to amine modified acidic resin catalysts.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included herein. In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings.
The term “amine modified acidic resin catalyst” as used herein refers to an acidic resin, a portion of the acidic functional groups of which have been neutralized by treatment with an amine. For example a sulfonated polystyrene resin in which about 5 to 50 percent of the SO3H groups have been converted to the corresponding pyridium salts upon treatment of the resin with the corresponding amount of the amine, pyridine, constitutes an amine modified acidic resin catalyst. The amine employed is distinct from any thiol promoter which itself comprises an amine group. Where the thiol promoter contains an amine group, for example as in cysteamine, the amine modified acidic resin catalyst is understood to comprise at least one other amine which is not a thiol promoter.
“BPA” is herein defined as bisphenol A and is also known as 2,2-bis(4-hydroxyphenyl)propane, 4,4′-isopropylidenediphenol and p,p-BPA.
“o,p-BPA” is herein defined as o,p-bisphenol A and is also known as 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane and 2,4′-isopropylidenediphenol.
As used herein the term “aromatic radical” refers to a radical having a valency of at least one and comprising at least one aromatic group. Examples of aromatic radicals include phenyl, pyridyl, furanyl, thienyl, imidazolyl, naphthyl, phenylene and biphenyl groups. The term includes groups containing both aromatic and aliphatic components, for example a benzyl group. Further, a C
3
-C
40
aromatic radical is an aromatic radical comprising between 3 and 40 carbon atoms. The 2-imidazolyl group (i) illustrates a C
3
aromatic radical.
As used herein the term “aliphatic radical” refers to a radical having a valency of at least one and comprising a linear or branched array of atoms which is not cyclic. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of carbon and hydrogen. Examples of aliphatic radicals include methyl, methylene, ethyl, ethylene, hexyl, and hexamethylene groups.
As used herein the term “cycloaliphatic radical” refers to a radical having a valency of at least one and comprising an array of atoms which is cyclic but which is not aromatic. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of carbon and hydrogen. Examples of cycloaliphatic radicals include cyclopropyl, cyclopentyl cyclohexyl and tetrahydrofuranyl groups.
As used herein the term “carbamyl group” refers to a functional group comprising the array of atoms OCONH. For example a carbamyl group is present the product of reaction of an alcohol with an isocyante as illustrated by the compound 1-naphthyl methylcarbamate, CAS No. 63-25-2.
As used herein the term “Boc group” refers to a an amine protecting group comprising the tertiary-butoxycarbonyl moiety. The combination of a nitrogen atom bearing both a hydrogen atom and the Boc group is an example of a carbamyl group.
The term “thiol promoter” as used herein refers to a molecule incorporating a thiol (SH) group. The thiol promoter acts to improve the rate and selectivity of bisphenol formation when a hydroxyaromatic compound is condensed with an aldehyde or ketone in the presence of an acidic catalyst relative to the same reaction carried out in the absence of the thiol promoter.
The term “silylmethanethiol” refers to a thiol compound in which a silicone atom and sulfur atom are each attached to the same carbon atom.
The instant invention provides a method of preparing a bisphenol, such as bisphenol A, by acid catalyzed condensation of a hydroxyaromatic compound, such as phenol, with an aldehyde, such as butanal, or a ketone, such as acetone, in the presence of a thiol promoter and an amine modified acidic resin catalyst.
The instant invention further provides amine modified acidic resin catalysts, which when used in the preparation of bisphenols, such as bisphenol A, provide selectivity advantages over known acidic resin catalyst systems. Amine modified acidic resin catalysts are prepared upon treatment of a polymeric material comprising acidic functional groups, such as sulfonic acid groups, with an amine in an amount such that between about 0.1 and about 50 percent of the acidic functional groups are neutralized. The amine modified acidic resins of the present invention are more selective catalysts, as measured by the greater selectivity for p,p-BPA formation observed when phenol and acetone are reacted in the presence of said amine modified acidic resin and a thiol promoter, relative to known acidic resin catalysts such as sulfonated polystyrene in combination with a thiol promoter.
Typically, the acidic resin catalyst which is converted to an amine modified acidic resin catalyst is a sulfonated polystyrene derivative comprising structural units I. Polymeric acidic resins comprising structure I are exemplified by
Amberlyst® 131, Amberlyst® 15 and Amberlyst® 36, all of which are strongly acidic ion exchange resins available from the Rohm and Haas Company.
Other suitable polymeric acidic resin catalysts which may be converted into the amine modified acidic resin catalysts of the present invention include Nafion® perfluorinated acidic resins available from the Dupont Company.
Typically, the acidic resin catalyst possesses between about 0.1 and about 6, preferably between about 2 and about 5 milliequivalents of acidic functional group per gram of resin. Typically, the acidic functional group is a sulfonic acid group. In the practice of the present invention it has been found advantageous to treat the acidic resin catalyst with a sufficient amount of an amine to neutralize between about 0.1 and about 50 percent, preferably between about 5 and
Caruso Andrew J.
General Electric Company
Johnson Noreen C.
Shippen Michael L.
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