Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Ion-exchange polymer or process of preparing
Reexamination Certificate
2003-02-21
2004-05-25
Ramsuer, Robert W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Ion-exchange polymer or process of preparing
C521S032000, C521S033000, C525S383000, C558S254000, C568S727000
Reexamination Certificate
active
06740684
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a process for producing a strong-acid cation exchange resin which comprises acid groups being partially neutralized with a mercaptoalkylamine.
Strong-acid cation exchange resins which comprise acid groups being partially neutralized with a mercaptoalkylamine and their use in the production of bisphenols is known in the art.
U.S. Pat. No. 3,394,089 describes a process for the preparation of bisphenol A from acetone and phenol in the presence of a strong-acid cation exchange resin wherein from 5 to 25 percent of the acid groups are neutralized with a C
1-4
-alkyl mercaptoamine. The mercaptoalkylamine is an effective promoter for the acid catalyzed condensation of phenol and acetone. The neutralization is carried out by direct contact with the C
1-4
-alkyl mercaptoamine or by exchange with its amine salt. According to the example an aqueous slurry of sulfonic acid cation-exchange resin in acid form is contacted with an aqueous solution of mercaptoethyl amine hydrochloride.
U.S. Pat. No. 5,212,206 discloses that the partially neutralized cation exchange resin as described in U.S. Pat. No. 3,394,089 is unsuitable in the bisphenol production because of the instability of the catalyst. To overcome this deficiency, U.S. Pat. No. 5,212,206 teaches that the strong acid cation-exchange resin is neutralized with a mercaptoamine in an anhydrous medium.
U.S. Pat. No. 4,584,416 discloses partial neutralization of a sulfonated ion exchange resin by means of an N-alkylamino alkyirnercaptan hydrochloride or hydrotosylate salt.
U.S. Pat. No. 5,589,517 discloses the partial neutralization of a sulfonated ion exchange resin by contacting the ion exchange resin with an N,N-dialkylmercaptoalkylamine, an N-mercaptoalkylpyrrolidine or an N-mercaptoalkylpiperidine.
U.S. Pat. No. 3,760,006 teaches that the modification of a strong-acid cation exchange resin in acid form by partial neutralization with a thiazolidine yields an improved catalyst for the preparation of bisphenol.
U.S. Pat. No. 4,595,704 discloses that known methods for producing partially neutralized ion-exchange resins employ azirine compounds which are somewhat hazardous. The U.S. patent suggests the use of less costly and less hazardous N-(2-mercaptoalkyl)amides to prepare a strong-acid cation exchange resin which is partially neutralized with an aminoalkanethiol.
U.S. Pat. No. 4,918,245 teaches that it has been known that markedly decreased amounts of Dianin's compound are produced as by-products in the bisphenol A production if an ion exchange resin is used as a catalyst of which the functional groups are modified with mercapto groups, such as by reaction with a mercaptoethylamine. On the other hand, the US patent also discloses that o,p′-isomer is still formed as a by-product in a large amount.
Unfortunately, sulfur-containing compounds which comprise a thiol group are sensitive to attack by oxygen and metals. Accordingly, the storage of these compounds without special care results in a reduced activity of strong-acid cation exchange resins which are partially neutralized with such compounds. When the partially neutralized strong-acid cation exchange resin is used as a promoter for producing bisphenol A, a variation in promoter quality may result in product variation, which is undesirable.
Accordingly, it would be desirable to find a new process for producing a strong-acid cation exchange resin comprising a plurality of acid groups being partially neutralized with a mercaptoalkylamine. It would be particularly desirable to find a process wherein the starting material used for neutralization is not sensitive to attack by oxygen and metals.
SUMMARY OF THE INVENTION
One aspect of the present invention is a process for producing a strong-acid cation exchange resin comprising a plurality of acid groups being partially neutralized with a mercaptoalkylamine, wherein a strong-acid cation exchange resin in acid form is contacted with an alkylcarbamoyl alkylthioester in the presence of water.
Another aspect of the present invention is a process of producing a bisphenol wherein a phenolic compound is reacted with a carbonyl compound in the presence of the strong-acid cation exchange resin produced according to the process above.
Yet another aspect of the present invention is a process for isomerizing by-products resulting from the production of a bisphenol by reaction of a phenolic compound with a carbonyl compound wherein the by-products are contacted with a strong-acid cation exchange resin produced according to the process above.
DETAILED DESCRIPTION OF THE INVENTION
The alkylcarbamoyl alkylthioester can be prepared by known methods, such as taught in Houben-Weyl, Volume IX, page 750, Georg Thieme editor Stuttgart, 1955. It is not sensitive to attack by oxygen and metals to a substantial degree.
Preferred alkylcarbamoyl alkylthioesters are represented by the formula I
R
1
—C(O)—NH—R
2
—S—C(O)—R
3
(I)
wherein
R
1
and R
3
each independently is a C
1-4
-alkyl group, preferably methyl, ethyl or propyl; and
R
2
is a C
2-6
-alkylene group.
More preferably, R
1
and/or R
3
is methyl. Most preferably, both groups R
1
and R
3
are methyl.
Useful C
2-6
-alkylene groups are ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, isopentylene, neopentylene, n-hexylene and all hexylene isomers. The most preferred C
2-6
-alkylene group is n-propylene.
Preferred alkylcarbamoyl alkylthioesters are thioacetylalkyl amides. More preferred are thioacetylalkyl acetamides, such as thioacetylethyl acetamide, thioacetyl-n-propyl acetamide, thioacetyl-isopropyl acetamide, thioacetyl-n-butyl acetamide, thioacetyl-isobutyl acetamide, thioacetyl-n-pentyl acetamide, thioacetyl-isopentyl acetamide, thioacetyl-neopentyl acetamide, thioacetyl-n-hexyl acetamide or isomers thereof The most preferred alkylcarbamoyl alkylthioester is a compound of formula I wherein R
1
and R
3
each are methyl and R
2
is n-propylene, that means thioacetyl-n-propyl acetamide.
The process of the present invention is employed to modify a strong-acid cation exchange resin. Strong-acidic cation exchange resin are known in the Art, see for example “Ullmann's Enzyklopaedie der Technischen Chemie”, 4th Edition, Vol. 13, pages 297 and following. Usually they have a polymeric matrix and functional ion exchange groups.
One known type of matrix is based on phenol/formaldehyde or benzene condensation polymers that are cross-linked with an aldehyde, a chlorinated hydrocarbon or an epoxy compound. The preferred matrixes are cross-linked polystyrene or cross-linked poly(alpha-methylstyrene) or a cross-linked polymer of styrene or alpha-methylstyrene which is substituted at the benzene ring with C
1-6
-alkyl, for example methyl, ethyl, tert. butyl or isopropyl, or with halogeno-C
1-6
-alkyl, such as chloromethyl, or with aminomethyl. The cross-linking agent preferably is divinylbenzene or trivinylbenzene.
The functional groups can be directly or indirectly bound to the polymeric matrix. For example the functional groups can be bound to the polymeric matrix via alkylene groups such as C
1-3
-alkylene groups, preferably ethylene or methylene with methylene being the most preferred group.
Functional groups typically are —SO
3
H or -PO
3
HR groups wherein R is hydrogen, a C
1-6
-alkyl group, such as a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, the pentyl or hexyl groups, a C
3-6
-cycloalkyl group, such as cyclohexyl, or aryl, such as phenyl or benzyl. The most preferred functional group is —SO
3
H. A part of the functional groups can be present in the salt form, for example in the alkali or alkaline earth metal salt form. However, preferably more than 95 percent, more preferably more that 99 percent, most preferably substantially all functional groups are in the acid form prior to partial neutralization according to the process of the present invention.
Examples of suitable strong-acid cation exchange resins include perfluorinated sulfonic acid resins, strong-acid resins prepared by phosph
Feord Damian M.
Frey Johann-Wilhelm
Paliuras Mihail
Dow Global Technologies Inc.
Ramsuer Robert W.
Small Andrea D.
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