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(12) United States Patent (10) Patent No.: US 7,074,944 B2 Steinbrenner Et Al

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(12) United States Patent (10) Patent No.: US 7,074,944 B2 Steinbrenner Et Al USOO7074944B2 (12) United States Patent (10) Patent No.: US 7,074,944 B2 Steinbrenner et al. (45) Date of Patent: Jul. 11, 2006 (54) METHOD FOR PRODUCING (51) Int. Cl. POLYTETRAHYDROFURAN C07D 307/77 (2006.01) (52) U.S. Cl. ........................................ ... 549/429 (75) Inventors: Ulrich Steinbrenner, Neustadt (DE), (58) Field of Classification Search ................. 5497.429 Martin Haubner, Eppelheim (DE): See application file for complete search history. Achim Gerstlauer, Ludwigshafen (DE); Thomas Domschke, Speyer (56) References Cited (DE); Christoph Sigwart, Schriesheim (DE); Stefan Kashammer, Schifferstadt U.S. PATENT DOCUMENTS (DE) 5,886,138 A 3/1999 Mueller (73) Assignee: BASF Aktiengesellschaft, 6,362,312 B1 3/2002 Eller et al. Ludwigshafen (DE) FOREIGN PATENT DOCUMENTS WO 99.36459 7, 1999 (*) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 OTHER PUBLICATIONS U.S.C. 154(b) by 333 days. Tanabe et al. Studies in Surface Sci. and Catalysis, vol. 51, 108-128, 1989. (21) Appl. No.: 10/485,685 Tanabe et al..Studes in Surface Sci. and Catalysis vol. 51, (22) PCT Filed: Jul. 26, 2002 199-210, 1989. Primary Examiner Taofiq Solola (86). PCT No.: PCT/EPO2AO8340 (74) Attorney, Agent, or Firm Novak Druce & Quigg, S 371 (c)(1) LLP, Jason D. Voight (87) PCT Pub. No.: WO03/014 189 In a process for the single-stage preparation of polytetrahy drofuran and/or tetrahydrofuran copolymers having a mean PCT Pub. Date: Feb. 20, 2003 molecular weight of from 650 to 5000 dalton by polymer (65) Prior PublicationO O Data ization of tetrahydrofurany over an acid catalvsty in the presence of at least one telogen and/or comonomer, the US 2004/O186269 A1 Sep. 23, 2004 telogen and/or comonomer is added at at least two addition points in different segments of the polymerization apparatus. (30) Foreign Application Priority Data Aug. 9, 2001 (DE) ................................ 101 39 293 8 Claims, No Drawings US 7,074,944 B2 1. 2 METHOD FOR PRODUCING Known catalysts include both systems which are homoge POLYTETRAHYDROFURAN neously dissolved in the reaction system and heterogeneous, i.e. largely undissolved, systems. The present invention relates to a process for preparing It is an object of the present invention to provide an polytetrahydrofuran or tetrahydrofuran copolymers by poly economical process by means of which polytetrahydrofuran merization of tetrahydrofuran over an acid catalyst, prefer and/or tetrahydrofuran copolymers having a particular mean ably a heterogeneous acid catalyst, in the presence of at least molecular weight can be prepared in higher polymer yields one telogen and/or comonomer, wherein the telogen and/or and/or space-time yields. comonomer is added at at least two addition points in We have found that this object is achieved by a process for different segments of the polymerization apparatus. 10 preparing polytetrahydrofuran (PTHF) and/or tetrahydrofu Polytetrahydrofuran, hereinafter referred to as PTHF and ran copolymers (THF copolymers) by polymerization of also known as polyoxybutylene glycol, is used as a versatile tetrahydrofuran over a heterogeneous acid catalyst in the intermediate in the plastics and synthetic fibers industries presence of at least one telogen and/or comonomer, wherein and is employed, inter alia, for producing polyurethane, the telogen and/or comonomer is added at at least two polyester and polyamide elastomers. In addition, it is, like 15 addition points in different segments of the polymerization Some of its derivatives, a valuable auxiliary in many appli apparatus. cations, for example as dispersant or in the deinking of waste The process of the present invention makes it possible to paper. obtain PTHF and THF copolymers having a particular mean PTHF is usually prepared industrially by polymerization molecular weight in high space-time yield and at a high of tetrahydrofuran, hereinafter referred to as THF for short, conversion, with the process of the present invention being over suitable catalysts. The addition of suitable reagents able to be carried out in one stage or in two stages. However, enables the length of the polymer chains to be controlled, preference is given to the single-stage synthesis of PTHF. and the mean molecular weight can thus be set to the desired It has surprisingly been found that the cascaded addition value. Control is achieved by choice of type and amount of of the telogen and/or comonomer at at least two different the telogen. Such reagents are referred to as chain termina 25 addition points in different segments of the polymerization tion reagents or “telogens'. Selection of appropriate telo apparatus enables the space-time yield and conversion to be gens also enables functional groups to be introduced at one improved significantly. The number of addition points can or both ends of the polymer chain. be two, three, four, five or more and depends on the Thus, for example, the use of carboxylic acids or car polymerization apparatus used, in particular its type and boxylic anhydrides as telogens results in formation of the 30 capacity, and also on process engineering and economic monoesters or diesters of PTHF which subsequently have to boundary conditions. However, preference is generally be converted into PTHF by saponification or transesterifi given to using from 2 to 5 addition points. cation. These processes are therefore referred to as two-stage Examples of Suitable polymerization apparatuses are cas PTHF processes. cades of at least two tank or tube reactors, for example Other telogens act not only as chain termination reagents 35 cascades of stirred tanks, cascades of at least two fixed-bed but are also incorporated into the growing polymer chain of reactors, which may optionally be operated with circulation, the PTHF. They have not only the function of a telogen but and cascades of loop reactors. In these polymerization simultaneously act as a comonomer and can therefore be apparatuses, one segment in which an addition point for the referred to as either telogens or comonomers with equal telogen and/or comonomer is located corresponds to a tank justification. Examples of Such comonomers are telogens 40 or a tube. However, it is not necessary for each segment of having two hydroxy groups, e.g. diols (dialcohols). These the polymerization apparatus in which an addition point for can be, for example, ethylene glycol, propylene glycol, the telogen and/or comonomer is located to be a single unit butylene glycol, 1,3-propanediol. 1,4-butanediol. 2-butyne Such as a stirred tank. Rather, a reactor can be configured so 1,4-diol, 1.6-hexanediol or low molecular weight PTHF. that it fulfills the function of a plurality of reactor elements Further suitable comonomers are cyclic ethers such as 45 connected in series. It is therefore also possible to use a 1.2-alkylene oxides, for example, ethylene oxide or propy single reactor, in particular a fixed-bed reactor, which is lene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydro divided into at least two, preferably from 2 to 5, segments by furan. The use of Such comonomers leads, with the excep means of Suitable internals, for example orifice plates or tion of water, 1,4-butanediol and low molecular weight sieve trays. Furthermore, it is possible to use stirred columns PTHF, to formation of tetrahydrofuran copolymers, herein 50 having more than one stage and flow tubes, each having at after referred to as THF copolymers, and in this way makes least two addition points. Particular preference is given to it possible to achieve chemical modification of PTHF. cascades of stirred tanks comprising at least two stirred In industry, use is predominantly made of two-stage tanks, preferably from 2 to 5 tanks. processes in which tetrahydrofuran is, for example, poly The telogen can be introduced into the polymerization merized in the presence of fluorosulfonic acid to form 55 either separately on its own or as a solution in the THF, with polytetrahydrofuran esters and these are Subsequently preference being given to a telogen content of from 1 to 50 hydrolyzed to polytetrahydrofuran. As an alternative, tet mol %, based on tetrahydrofuran. Comonomers can likewise rahydrofuran is, for example, polymerized with acetic anhy be introduced into the polymerization as solutions in THF, in dride in the presence of acid catalysts to form polytetrahy which case the comonomer content can be up to 30 mol %, drofuran diacetate which is Subsequently transesterified, e.g. 60 preferably 20 mol %, based on tetrahydrofuran. However, by means of methanol, to give polytetrahydrofuran. Disad the THF and the telogen and/or comonomer are preferably vantages of Such processes are that they have to be carried introduced separately into the polymerization reactor. out in two stages and that by-products such as hydrofluoric Since the telogen effects termination of the polymeriza acid and methyl acetate are formed. tion, the mean molecular weight of the PTHF or the THF The single-stage synthesis of PTHF is carried out by 65 copolymers can be controlled via the amount of telogen polymerization of THF using water, 1,4-butanediol or low used. The more telogen present in the reaction mixture, the molecular weight PTHF as telogen over acid catalysts. lower the mean molecular weight of the resulting PTHF or US 7,074,944 B2 3 4 THF copolymers. Depending on the telogen content of the Preference is given to water, ethylene glycol. 1,3-pro polymerization mixture, it is possible to prepare PTHF and panediol. 1,4-butanediol. 1.5-pentanediol, 1.6-hexanediol. THF copolymers having mean molecular weights of from polytetrahydrofuran having a molecular weight of from 200 650 to 5000 dalton, preferably from 650 to 3 000 dalton and to 700 dalton, 1.6-hexanediol, 1,8-octanediol, 1,10-de particularly preferably from 1 000 to 3 000 dalton.
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