FI86841B - Method for production of (1-phenylethyl)hydroquinone - Google Patents

Description

1 86841

The present invention relates to linear polyesters, and more particularly to optically anisotropic liquid crystal polyesters prepared by melt, and relates to a process for the preparation of (1-phenylethyl) hydroquinone.

Liquid crystal polyesters, or those having optical anisotropy in the molten phase, are well known in the art. Numerous patents describe such polyesters and some are generally described, for example, by W.J. In an article published by Jackson, Jr. in the British Polymer Journal in December 1980, 15 entitled "Liquid Crystal Polymers IV Liquid Crystalline Aromatic Polyesters."

Some aromatic polyesters have optical anisotropy in the molten state and can be melt-spun into crystalline fibers which, in the subsequent heat treatment, further crystallize and substantially improve in toughness. Such heat-treated polyester fibers can be used for a variety of purposes, for example, in ring cards and other industrial and consumer products that require high strength and low weight with associated economic and other advantages. Specific applications for this type of liquid crystal polyester include high strength reinforcements for a variety of thermoplastic and thermosetting polymeric materials.

In addition to being used as fibers, such polyesters 30 can also be used in molds, for example by injection molding, as molded bodies in a wide variety of substrates with excellent rigidity and toughness and strength.

The parent application, i.e., F1 patent application 853,765, discloses an improved, low cost, high performance, thermotropic polyester that is optically anisotropic in the melt phase and is formed into fibers or molds by molding into other useful articles using conventional conventional molding. and design technology.

The melt-spinnable liquid crystal polymers contemplated herein are fiber-forming molecular weight and are optically anisotropic in the molten phase and contain repeating groups of formulas I and II.

15 y ch3-ch 2 O and optionally either groups of formula III or groups of formula IV or both (R) 25 ^ I / - \ x -O \ o- '-7 (III) (IV) 30 wherein R is 1- Alkyl having 5 carbon atoms, e.g. methyl or tertiary butyl. Preferably, the polymer consists essentially of groups I, II and III, and most preferably with a molar ratio between about III and II of about 1.

The polymers contemplated herein, that is, those having the groups of formulas I and II described above and optionally of either formula III or formula IV or both, are formed by reacting polyester-forming precursors containing said groups with polyester-forming precursors. The reaction conditions. Thus, they can be formed by solution polymerization, which is a preferred method, as well as by melt or emulsion polymerization. They can be formed from diacids, diacid halides, diols or esters by transesterification. To carry out the preparation in a preferred manner, the polymers are synthesized by a solution polymerization process in which the group I precursor is terephthaloyl chloride. The preferred Group II precursor is (1-phenylethyl) hydroquinone, and the preferred Group III precursor is phenylhydroquinone and the preferred Group IV precursor is C1-C5 alkyl substituted hydroquinone.

When synthesizing and recovering the polymer, the polymer can be formed from the usable shaped articles referred to above by conventional methods. Thus, for example, the polymer can be extruded and formed into pellets to obtain a compacted product, which product can then be fed to another extruder and formed into various articles such as fibers using a spinneret or films or sheets using any film or sheet forming nozzle. In addition, the material can be injection molded into various configurations using a conventional injection molding method. When forming into fibers, it is desirable to heat treat the fiber roll. This can be accomplished simply by heating the fiber roll 30 while the fibers are at rest in an inert atmosphere, such as a stream of nitrogen, to a sufficient temperature and for a sufficient time to significantly increase the toughness. It is at least about 50% to increase toughness. Such heat treatment is also desirable for other items, e.g., sheets, films, and molded articles.

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Those skilled in the art will be accustomed to selecting the particular starting materials used and it will be readily apparent to them that polymer grade starting materials should be used. In addition, for the most commendable results, it is desirable to use 5 stoichiometric amounts of reactants. In passing, it should be mentioned that, in general, the molar ratio between group II and group III and / or group IV can vary over a wide range. For example, in a preferred terpolymer of groups I, II and III, the ratio of group II to group III is suitably about 1: 4 to about 4: 1, desirably about 1: 2 to about 2: 1, and more equimolar amounts to obtain more preferred results.

As previously indicated, Group II is preferably incorporated into a thermotropic polyester using (1-phenylethyl) hydroquinone as the monomer. In addition, as indicated, such a group can be incorporated into a polyester using an ester derivative thereof. Such ester derivatives are customarily prepared by those skilled in the art using (1-phenylethyl) hydroquinone as the starting material.

It is known from Chemical Abstracts (1953) Vol. 47, 1638b that when styrene and hydroquinone are reacted in toluene in the presence of Lewis acid (sulfuric acid) using hydroquinone in the same molar amount as styrene, almost exclusively 2,5-bis derivatives of hydroquinone are formed .

However, it has now been found that an important method for synthesizing (1-phenylethyl) hydroquinone is to react styrene with hydroquinone in the presence of an organic diluent, preferably ether, and effective reaction-stimulating amounts of Lewis acid.

The invention thus relates to a process for the preparation of (1-phenylethyl) hydroquinone, in which styrene and hydroquinone are reacted in the presence of an organic diluent and effective reaction-stimulating amounts of 35 Lewis acid, which process is characterized in that the reaction is carried out using Lewis p-toluenesulfonic acid and tetraethylene glycol dimethyl ether as the organic diluent and using a molar excess of hydroquinone, and that (1-phenylethyl-5H) hydroquinone is recovered by distillation, whereby the organic diluent distills off the unreacted hydrogen.

The reaction is preferably carried out at about 135 ° C to about 145 ° C and the crude product is purified by portionwise distillation in vacuo.

The tetraethylene glycol dimethyl ether used as a diluent in the process, that is, a material of the formula CH3 (OCH2CH2) 4OCH3, which is commercially available under the trade name Tetraglyme material. 15 pratoluenesulfonic acid is used as the Lewis acid. It is preferred to purify the crude (1-phenylethyl) hydroquinone product by distillation using sodium hydrogen sulfite to neutralize the para-toluenesulfonic acid catalyst.

The preferred method for synthesizing melt-processed aromatic liquid crystal polyesters referred to above is the solution polymerization method, and as also referred to above, it is preferred that the starting materials be terephthaloyl chloride, (1-phenylethyl) hydroquinone or optionally either phenylhydroquinone or phenylhydroquinone. Obviously, such a reaction is carried out in the presence of a hydrochloric acid trap. Suitable hydrochloric acid traps or purifiers are organic bases, for example aliphatic and aromatic amines, in particular tertiary amines. The preferred trap is pyridine and is preferred to be used in excess, for example up to a 50% molar excess of such material. The solvents used in the solution polymerization are customarily chosen by those skilled in the art, but it is generally preferred to use low molecular weight chlorinated hydrocarbons such as fully or partially chlorinated C1-C3 alkanes such as trichloromethane, trichloroethane, with dichloromethane being preferred.

Although the foregoing describes the present invention in sufficient detail to enable one skilled in the art to do and use the same, a method for industrial application of the present invention nevertheless follows.

Preparation of (1-phenylethyl) hydroquinone A 50 liter three neck round bottom flask 10 is charged with 5 kg (45.4 moles) of hydroquinone (technical hydroquinone grade available from Eastman Chemical Products, Inc.). In addition, 10 liters of Tetraglyme material and 60 grams (0.32 moles) of para-toluenesulfonic acid monohydrate are charged. A mechanical stirrer equipped with a ground glass shaft is used and the reagent mixture is heated to about 140 ° C with slow stirring. Maintaining this temperature, 4.166 kg (40 moles) of styrene are added over about 90 minutes. During the addition of styrene, a slight exotherm occurs and the temperature is maintained at about 140 ° C (± about 5 ° C). When the addition of styrene is complete, the reaction mixture is kept at this temperature for approximately 5 hours, after which time the heating and stirring are stopped and the mixture is allowed to cool overnight. The crude product has the appearance of heavy engine oil 25 in both relative viscosity and color and is homogeneous and does not contain suspended solids. The yield is about 19.316 kg.

The crude product is purified portionwise by vacuum distillation using a 12-liter flask equipped with 30 bottom boilers, stirrers, and vacuum on a 121.92 cm x 5.08 cm (4 feet x 2 ") column packed with approximately 76.2 cm (30 ") with corrugated metal wire mesh filling, refrigerated reflux condenser, heat tracer distillate reflux distributor, front-35 vessel and associated piping In a typical distillation, approximately 10 kg of crude product is charged with about 31 grams of sodium salt using about 31 grams of sodium toluenesulfonic acid catalyst The distillation decomposition of one distillation is shown in Table I. One redistillation of all the best fractions (fractions 4 & 5) easily yields more than 96% yield of (1-phenylethyl) hydroquinone product.

Table I

Distillation of 10 (1-phenylethyl) hydroquinone at a batch weight of 10,000 grams

Fraction Weight Temperature ° C Composition (g) RFX / REB @ P%%%% 15 Sty-

_reeni HQ / TG PEHQ DPEHQ

1,150 1220C / 162 ° C 20 80 ___ @ 3 mmHg________ 2 3030 130 ° C / 163 ° C <2 95 <2 20 ____ @ 2 mmHg____ 3 2225 124 ° C / 189 ° C - 95 <3 _ @ 0.4 mmHg__ 4 925 174 ° C / 212 ° C - 7 93 _ @ 25 mmHg ___________ 25 5 2103 198 ° C / 249 ° C 4 94 2 _ @ 0.6 mmHg ____ 6 142 205 ° C / 265 ° C - - 50 50 ________ @ 0,7 mmHg_______ Residual 3078 -------- -_ 2_85 RFX = reflux REB = flask with bottom boiler P = pressure 35 HQ = hydroquinone s 86841 TG = Tetraglyme material PEHQ = (1-phenylethyl) hydroquinone DPEHQ = di (phenylethyl) hydroquinone - probably a mixture of 2,5-DPEHQ and 2,6-DPEHQ 5 Preparation of the polymer

The polymer was synthesized using a reactor equipped with both cooling and heating and a reflux condenser. The reaction was generally carried out using a moderate nitrogen flow atmosphere and substantially atmospheric pressure.

A solution containing 14.7 kg (68.7 moles) of (1-phenylethyl) hydroquinone and 12.8 kg (68.7 moles) of phenylhydroquinone, 48.2 kg of methylene chloride and 21.7 to about 26 moles was formed in the reactor. 1 kg of pyridine. The preferred order of addition is (1-phenylethyl) hydroquinone, pyridine, methylene chloride and phenylhydroquinone. Approximately 27.9 kg (137.4 moles) of tetraphthaloyl chloride was dissolved in about 83.7 kg of methylene chloride. The tetraphthaloyl chloride solution was added to the diol solution at a rate of approximately 2.7 kg per 20 minutes for about 20 minutes and then about 5.4 kg per minute for the remaining 10 minutes with vigorous stirring and maintaining the reactor temperature substantially at about 2 ° C (about 35 ° F). It is desirable not to allow the slurry temperature to exceed about 24 ° C (about 75 ° F). At the end of the addition of the Te-25 phthaloyl chloride / methylene chloride solution, the reactor temperature was maintained at about 2 ° C for one hour with stirring. 454 kg of deionized water was then added to the reaction mass and the temperature of the slurry was raised to about 41 ° C (about 104 ° F) to extract methylene chloride by distillation. After most of the methylene chloride, e.g., about 85%, was removed, the slurry temperature was raised to 85 ° C (185 ° F) and held there for approximately 1 hour with further removal of methylene chloride. The hot slurry was then fed to a rotary drum filter. The remaining wet cake was then re-slurried with an additional 454 kg of water, heated to approximately 85 ° C (185 ° F) and maintained at that temperature for approximately 1 hour before re-feeding the material to the rotary drum filter. The filtered wet cake was then reslurried using about 454 kg of acetone with the slurry heated to approximately 54 ° C (130 ° F) and held at that temperature for about 1 hour. The slurry was re-filtered and the wet cake was combined with 454 kg of additional acetone, after which this slurry was again heated to about 54 ° C (130 ° F) and maintained at that temperature for 1 hour before re-separating the solids with a rotary drum filter. The final wet cake was dried in a vacuum oven at approximately 121 ° C (250 ° F) at 67.7-15.8.0 kPars (508-660 mmHg) overnight.

The dried polymer typically has a melting point of about 320 ° C and a logarithmic viscosity number of about 0.6 to about 1.2 (dl per gram) at a concentration of about 0.5 (grams per 100 ml) in a solvent of the same volumes of trifluoroacetic acid and methylene chloride. This thermotropic polymer, which is optically anisotropic in the molten phase, can be melt-spun into fibers, extruded into films or sheets, and, as previously shown, injection molded into molds 25 to form a plurality of substrates, e.g., substrates for use on printed circuit boards. As indicated above, such objects are heat-treated.

In forming fibers having a single strand diameter of, for example, about 10 to 30 microns, the polymer is first pelletized by extruding the material into a rod, followed by cooling and then cutting the rod into pellets having a size of about 3-5 mm. Typical drum temperatures in the extruder are about 35,340 ° C. The pellets are then loaded into another conventional extruder and formed by the spinneret into fibers that can be wound on a wrapper using conventional wrapping equipment. The rolls are formed as desired by twisting onto a metal core. The rolls containing dormant fibers are then heat treated under a nitrogen atmosphere at a temperature of about 302 ° C for about 22 hours (a period of about 5 hours of reaching temperature and about 17 hours of holding). Typical properties of heat-treated crystalline monofilaments are as follows: toughness typically about 18 to about 20 grams per denier (calculated based on Instron breaking load measurement using a measurement length of 12.7 mm at 5 mm per minute and density and cross-sectional area measurement); a modulus of elasticity typically of about 510 to about 750 per 15 grams of denier; and elongation at break 3 - 4%.

As indicated above, fusible, molecular weight fiber-forming liquid crystal polyesters that are optically anisotropic in the melt can also be formed by replacing all or part of Group III with Group IV.

In Group IV, R is alkyl of 1 to 5 carbon atoms, including, for example, methyl and tertiary butyl. Preferred starting materials when it is desired to form a polyester containing a Group IV are alkyl-substituted hydroquinones, although, of course, other polyester-forming precursors may be used. Although the proportion of Group IV may vary when such a group is included in the polyester instead of Group III, it is generally used relative to Group II in an amount of about 9: 1 to 1: 9. Preferably, when using Group IV, wherein R is CH 3, the ratio of Group IV to Group II is 8: 2 to 9: 1 to produce heat-treated fibers of suitable toughness; when the ratio of group IV to group II is about 2: 8 to 8: 2, the polymers generally have melting points that are too low (e.g., 35 below about 300 ° C) for the desired effective heat treatment! - 11 86 8 41

Ic. When R is a t-butyl group, the preferred ratio of group IV to group II is 3: 7 to 8: 2. Such polyesters have melting points of 300 ° C to about 350 ° C. Furthermore, while the proportions may again vary with the polyester 5 used containing both Group III and Group IV, Group IV

the relative amounts relative to the Group III amounts are suitably from about 1: 4 to about 4: 1. Heat-treated fibers, when Group IV is used to exclude Group III, typically have the following properties: toughness 10 10 to 15 grams per denier (same as above except rate 2 mm per minute); a factor of about 250 to 500 grams per denier; and elongation about 3 to 5%. The properties of the heat-treated fibers, which essentially contain only groups I and II, are generally the same as those of the polyesters containing groups I, II and IV.

Although the foregoing illustrates the present invention, it is, of course, apparent that variations which follow patent regulations and laws and do not depart from its spirit and scope are possible.

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Claims (1)

12 86841 Patenttivaatimus Menetelmä (1-phenylethylethyl) hydroquinonine valmistamiseksi, jolloin styrenei ja hydroquinoni saatetaan reacto laimentimena tetraethyleneiglycolidimethyl ether et al. 10 käyttämällä hydroquinonia molaarisesti ylimäärin, ja etä (1-phenylethylethyl) hydroquinone otetaan talteen tislaamalla, jolloin organineninen laimennin tislautuu reagoimatta jääinen hydrokinoni Process for the preparation of (1-phenylethyl) hydroquinone, reacting styrene and hydroquinone with each other in the presence of an organic diluent and effective reaction-stimulating amounts of a Lewis acid, characterized in that the reaction is carried out by using p-toluenesulfonic acid such as Lewis acid and tetraethylene glycol dimethyl ether as an organic diluent and using the hydroquinone in a molar excess, and that (1-phenylethyl) hydroquinone is recovered by distillation, the organic diluent being distilled together with the unreacted hydrogen. .