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Process for Making Amidine-Containing Copolymers

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Process for Making Amidine-Containing Copolymers lllllllllllllllllllilllilllIlllllllllllllllllllllllllllllllllllllllllllllll US005324792A United States Patent [191 [11] Patent Number: 5,324,792 Ford I ~ [45] Date of Patent: Jun. 28, 1994 [54] PROCESS FOR MAKING In?ammatory Bowel Disease,” J. Med. Chem, 26, p. AMIDINE-CONTAINING POLYMERS 1300, (1983). [75] Inventor: Michael E. Ford, Coopersburg, Pa. Neil S. Isaccs, “Physical Organic Chemistry” John Wiley & Sons, New York, p. 284. [73] Assignee: Air Products and Chemicals, Inc., Allentown, Pa. Primary Examiner-Bernard Lipman [21] Appl. No.: 146,247 Attorney, Agent, or Firm—Mark L. Rodgers; William F. [22] Filed: Nov. 2, 1993 Marsh Related US. Application Data [57] ABSTRACT [62] Division of Ser. No. 36,757, Mar. 25, 1993. Amine functional polymers which are terpolymers made up of randomly linked units of amidine or [51] Int. Cl.5 .............................................. .. O08F 8/12 amidinium formate, N-vinylformarnide and either vinyl [52] US. Cl. ............................... .. 525/378; 525/328.2; 525/379 amine or vinylamrnonium formate are prepared by [58] Field of Search .............................. .. 525/378, 379 aqueous hydrolysis of poly(N-vinylformamide) at a temperature in the range of 90° to 175° C., preferably in [56] References Cited the presence of a minor amount of ammonia or volatile U.S. PATENT DOCUMENTS amine. Best conversions and good control of polymer structure are obtained at 140° C. to 160° C. with a small 4,393,174 7/1983 Dawson et al. ................... .. 525/369 4,421,602 12/1983 Brunnmueller et a1. .. 162/ 168.2 concentration of ammonia or alkylamine. Formation of 4,444,667 , 4/1984 Burkert et a1. .. 525/383 poly(vinylammonium formate) containing no other salts 4,578,515 3/1986 Dawson et al. 525/377 or ionic coproducts is realized by degassing the hydro 4,808,683 2/1989 Itagaki et a1. ............ .. .. 525/328.2 lyzate to remove ammonia or amine from the polymer‘ 4,943,676 7/1990 Pinschmidt, Jr. et a1. ....... .. 525/383 solution. The poly(vinylamrnonium formate) affords 4,957,977 9/1990 Itagaki ct al. .................. .. 525/328.2 distinct advantages in the production of salt-free poly 5,064,909 11/1991 Itagaki et al. .................. .. 526/3282 5,194,492 3/1993 Pinschrnidt, Jr. et a1. .... .. 525/328.2 mers by catalytic decomposition of impurities. Poly( vinylamines) containing signi?cant amounts of amidine FOREIGN PATENT DOCUMENTS functionality offer advantages in, applications where 61-118406 6/1986 Japan . increased basicity is required. OTHER PUBLICATIONS J. P. Brown et al, “A Polymeric Drug for Treatment of 8 Claims, No Drawings 5,324,792 1 2 containing 90 to 10 mol percent vinylamine units and 10 PROCESS FOR MAKING AMIDINE-CONTAINING to 90 mol percent N-vinylamide units in random distri POLYMERS bution. The product described has no amidine units. Hydrolysis conditions disclosed involve the use of acids This is a division of application Ser. No. 08/036,757 5 or bases at temperatures from 20° to 200° C. Particularly ?led Mar. 25, 1993. preferred temperatures are 70° to 90° C., which is the range within which all the operative examples fall. FIELD OF THE INVENTION When using acid hydrolysis, exempli?ed by hydrochlo- ' This invention relates to poly(vinylammonium for ric acid, the pH is 0 to 5. In an alkaline medium, exem mate) and to a process for its manufacture. In another pli?ed by 10% sodium hydroxide solution, the pH is 9 aspect it relates to a process for making amidine-con to 14. It is stated that it is also possible to use ammonia, taining terpolymers by controlled aqueous hydrolysis of an amine or an alkaline earth metal base such as calcium poly(N-vinylformamide). hydroxide, or aqueous solutions of ammonia or an amine. This is not demonstrated, but it states that if the BACKGROUND OF THE INVENTION 15 solvolysis is carried out in ammonia or an amine, form Interest in amine functional polymers has grown rap amide or a substituted formamide is obtained as a by idly in recent years owing to their demonstrated utility product. in a broad spectrum of operations which capitalize on The use of ammonia or a primary or secondary amine their solubility in water and their reactivity under rela in the manufacture of water soluble poly(vinylamine) is tively mild conditions. Such polymers have found uses 20 disclosed in Japanese Laid-Open Patent Application as ?occulants, ?ltration aids, paper strengthening No. 61-1184-06 (1986), but in this procedure ammonia or agents, in enhanced oil recovery and as crosslinking' amine is used as a puri?cation acid prior to base hydro agents for epoxy resins and polyurethanes. As the com lysis using a‘ strongly basic material, preferably sodium mercial value of these polymers has become recognized, or potassium hydroxide, at 20° to 100° C. There is no more and more attention has been devoted to develop 25 indication of amidine formation. ing polymers containing amine functionality but tai While it is recognized that carboxamides can be hy lored to speci?c needs. drolyzed under either acidic or basic conditions to Poly(vinylamine) (pVA) is perhaps the most promis amines, from a practical point of view it is said to be ing of amine functional polymers because of its simplic advantageous to hydrolyze amides under acidic cataly ity of manufacture and its versatility. Since its theoreti 30 sis, using conditions normally employed for protein cal monomeric unit, vinylamine, is unstable, pVA is degradation. See Physical Organic Chemistry, N. S. made indirectly by polymerizing a vinylarnide, such as Isaacs, John Wiley and Sons, New York, (1987) pp. N-vinylformamide, and hydrolyzing the resulting poly 484-485. In either case, however, when applied to the mer to develop its amine functionality. Complete hy conversion of poly(N-vinylformamide) (pNVF), inor drolysis is dif?cult if not impossible to achieve and it is 35 ganic coproducts are formed along with the poly( well recognized that polymers made by this route and vinylamine). Base hydrolysis leads to alkali metal salts, referred to as homopolymers of vinylamine are actually such as sodium or potassium formate, while acid hydro copolymers containing vinylamine units (perhaps as lysis gives the corresponding salt of poly(vinylamine) high as 98 mol percent) and N-vinylformamide units. A and formic acid. Neutralization provides poly(vinyla third unit, amidine, has also been recognized as an impu mine) (pVA) accompanied by a salt of the acid used for rity which is to be minimized in order to increase pri hydrolysis and, unless formic acid has been removed, a mary amine functionality. formate salt. It has been known for over a decade that hydrochlo The desirability of a salt-free product is recognized in ric acid hydrolysis of poly(N-vinylacetarnide) does not U.S. Pat. No. 4,943,676, Pinschmidt, Jr. et a1. (1990). produce an absolute homopolymer but a product con The problem is addressed by avoiding the hydrolysis taining both amine and amidine units resulting from the procedure altogether. As disclosed in this patent, pNVF acid-catalyzed condensation of adjacent amine and ac is subjected to a thermolytic reaction by heating to a etamido groups. See J. P. Brown et al., Journal of Me temperature sufficient to effect thermodecarbonylation dicinal Chemistry, 26, 1300 (1983). This article, citing and yield a polymer containing free amine functionality. unpublished work of Dawson and Brock, states on page This product also contains amidine linkages formed 1304 that the amidine formation can be avoided by use from adjacent formamide and amine groups with loss of of alkaline hydrolysis media. , water. The polymer product disclosed contains ran U.S. Pat. No. 4,393,174, Dawson et a1. (1983) expands domly linked units of vinylamine, amidine and N-vinyl on the Brown et a1. disclosure in describing the prepara formamide. The amidine units are said to be unwanted tion of poly(N-vinylacetamide) and poly(N-vinylforma 55 and can be suppressed by the presence of water which mide) with subsequent hydrolysis to poly(vinylamine) drives the equilibrium reaction back to the amine and which is useful in making polymeric dyes. It is pointed formamide moieties. out that hydrolysis of the amide groups is not easy and None of the prior art appears to recognize the desir has typically been carried out in re?uxing aqueous hy ability of forming the amine-amidine-arnide terpolymer drochloric acid. Such conditions are said to result in disclosed by Pinschmidt, Jr. et a1., nor does the art amidine formation as an impurity which can be avoided suggest how to obtain such a polymer by hydrolysis of by carrying out the hydrolysis at temperatures between pNVF. 110° and 170° C. in an aqueous strong base such as SUMMARY OF THE INVENTION NaOH. U.S. Pat. No. 4,421,602, Brunnmueller et al., (1983) 65 In accordance with my invention a process is pro discloses making homopolymers of N-vinylformamide vided which enables the controlled and reproducible which are partially hydrolyzed so that from 10 to 90% production of an amine functional polymer which is a of the formyl groups are split off to obtain a polymer terpolymer of the monomeric units vinylamine, N 5,324,792 3 4 vinylformamide and amidine. In making my invention I below 100'’ C. Such lower boiling amines are preferably recognized that this amidine-containing polymer, which lower alkylamines such as methylamine, dimethylam is only generally disclosed by Pinschmidt, Jr. et al., ine, trimethylamine, ethylamine, diethylamine, triethyl cited above, is capable of offering certain advantages, amine, isopropylamine, diisopropylamine, propylamine, meriting the development of a process for its intended and the like. Primary or secondary amines are favored production. According to my invention a terpolymer of for this service. Ammonia is, however, the preferred vinylamine, N-vinylformamide and amidine is made by agent because of the ease with which it can be added subjecting poly(N-vinylformamide) to aqueous hydro ~ and removed once the hydrolysis is completed.
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