Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-09-18
2003-03-18
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S727000
Reexamination Certificate
active
06534686
ABSTRACT:
BACKGROUND OF THE INVENTION
This disclosure relates to a method for producing and using catalysts for the production of bisphenols, and in particular to a method for producing catalysts which contain attached mercaptan promoters, and using these catalysts in the production of bisphenol-A, and its derivatives.
Typical bisphenols, such as 4,4′-isopropylidenediphenol, e.g., bisphenol-A (BPA), are widely employed as monomers in the manufacture of polymeric materials, such as engineering thermoplastics. For example, BPA is a principal monomer used in the manufacture of polycarbonate. Bisphenols are generally prepared by the electrophilic addition of aldehydes, or ketones such as acetone, to aromatic hydroxy compounds such as phenol, in the presence of an acidic catalyst composition. These types of reactions are also referred to as acid catalyzed condensation reactions. Commercially, sulfonated polystyrene resin cross-linked with divinylbenzene, e.g., PS-DVB, is typically used as a solid acid component of the catalyst composition. Reaction promoters can also be employed as part of a catalyst composition to improve the reaction rate, and selectivity, of the desired condensation reaction; in the case of BPA, the desired selectivity is for the para-para isomer. Promoters can be present as unattached molecules in the bulk reaction matrix, e.g., “bulk-promoters”, or can be attached to the resin through ionic linkages, e.g., “attached-promoters”. A useful class of promoter is the mercaptans, specifically thiols, e.g., organosulfur compounds which are derivatives of hydrogen sulfide. Unfortunately, due to the reactivity of the S—H sulfhydryl functionality, thiol promoters are prone to deactivation during their synthesis and under typical conditions used to attach the promoter to the resin, because they readily oxidize at the sulfur atom to inactive disulfide compounds, with —S—S— linkages, that do not function as promoters in the catalytic production of bisphenols. Consequently, a long felt yet unsatisfied need exists for a new and improved method to attach mercaptan promoters to catalyst supports to produce highly active and selective catalysts for the production of bisphenols.
SUMMARY OF THE INVENTION
In one embodiment, the present disclosure is drawn to method for producing a catalyst composition which catalyzes the formation of bisphenols from aromatic hydroxy compounds and carbonyl containing compounds, said method comprising the step of attaching a sulfur-protected mercaptan promoter component to a solid acid support component comprising a protic acid functionality, said sulfur-protected mercaptan promoter component having the following structure (I),
wherein R
1
is a functionality selected from the group consisting of a positively charged ammonium functionality, a positively charged guanidinium functionality, a positively charged phosphonium functionality, and a neutral amine;
wherein a is between about 0 and about 11; and
wherein R
2
is a sulfur protecting functionality which is one member selected from the group consisting of a tertiary alkyl functionality, an ester functionality, a carbonate functionality, and a benzyl functionality which is attached to the sulfur atom via the benzylic methylene carbon.
In another embodiment, the present disclosure is drawn to a method for forming bisphenols, comprising the step of reacting an aromatic hydroxy compound with a carbonyl compound in the presence of a catalyst composition, said catalyst composition comprising a solid acid component and a sulfur-protected mercaptan promoter component having the following structure (I),
wherein R
1
is a functionality selected from the group consisting of a positively charged ammonium functionality, a positively charged guanidinium functionality, a positively charged phosphonium functionality, and a neutral amine;
wherein a is between about 0 and about 11; and
wherein R
2
is a sulfur protecting functionality which is one member selected from the group consisting of a tertiary alkyl functionality, an ester functionality, a carbonate functionality, and a benzyl functionality which is attached to the sulfur atom via the benzylic methylene carbon.
DETAILED DESCRIPTION
The present disclosure is directed to a method for producing and using catalysts for the production of bisphenols, and is suitable for the preparation of attached-promoter catalysts, which can effectively catalyze the formation of bisphenols from aromatic hydroxy compounds and carbonyl containing compounds. In the context of the present disclosure, the term “catalyst” refers to a composition, wherein the individual constituents of the composition are referred to as “components”. In the context of the present disclosure, a typical catalyst comprises a “support” component that is generally a polymeric material, also referred to as a “resin”, comprising a protic acid functionality, and a “promoter” component that is generally an organic compound. As used herein, the term “functionality” is defined as an atom, or group of atoms acting as a unit, whose presence imparts characteristic properties to the molecule to which the functionality is attached. In the context of the present disclosure, a “protic acid functionality” is defined as a group of atoms that are covalently attached to the polymeric support component of the catalyst, which can act as a source of protons, e.g., a Brönsted acid, and upon deprotonation the counter-anion can serve as an anionic moiety of an ionic bond with a cationically charged promoter component. A suitable example of a support component is a polystyrene resin, cross-linked with divinylbenzene. Suitable examples of protic acid functionalities, which are attached to the support component, are a sulfonic acid functionality, which upon deprotonation produces a sulfonate anion functionality, a phosphonic acid functionality, which upon deprotonation produces a phosphonate anion functionality, and a carboxylic acid functionality, which upon deprotonation produces a carboxylate anion functionality. For example, in one embodiment of the present disclosure, the support component is a polystyrene resin, cross-linked with 4% of divinylbenzene, and functionalized with sulfonic acid groups.
Attached-promoter components are typically organic compounds, which can readily form stable cationic species. Suitable examples of promoters include, but are not limited to, alkylammonium mercaptans, alkylguanidinium mercaptans, alkylphosphonium mercaptans, and aminomercaptans. As used herein, the term “mercaptan” is defined as an organosulfur compound, which is a derivative of hydrogen sulfide, and the term “aminomercaptan” is defined as an organosulfur compound, which further comprises a nitrogen functionality. Suitable examples of aminomercaptans include, pyridyl mercaptans, benzimidazole mercaptans, phthalimido mercaptans, benzothiazole mercaptans, and imidazole mercaptans. In the case of aminomercaptans that comprise ring systems, a sulfur containing chain can be bonded to the ring system at any one of ring location that is capable of bonding a substituent. For example, in the case of aminopyridine mercaptans, a sulfur containing functionality can be appended to pyridine ring at the 2, 3, or 4 ring position. Furthermore, in each of the classes of mercaptan promoter listed above, i.e. alkylammonium mercaptans, alkylguanidinium mercaptans, alkylphosphonium mercaptans, and aminomercaptans, more than one sulfur containing chains per amino group can be present in the promoter. For example, in the case of pyridyl mercaptans, the pyridine ring can be substituted with up to 5 sulfur-containing chains. Substituent groups, which are typically represented by the symbol R in chemical structures, can also be attached to a promoter to adjust the promoter's electronic properties, steric properties, and combinations thereof, to affect the reactivity of the overall catalyst composition. Suitable promoter substituent groups include, but are not limited to, a hydrogen, a fluoride, a bromide, a chloride, an iodide, a vinyl group, a hydroxide, a
Spivack James Lawrence
Webb Jimmy Lynn
Caruso Andrew J.
Johnson Noreen C.
Shippen Michael L.
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