United States Patent Office Patiented Jan

3,165,556 United States Patent Office Patiented Jan. 12, 1965, 2 ence of excessive amounts of water. In fact, the presence 3,165,556 of water has always been considered to be deleterious in PREPARATION OF DEVNY AND TETRAWNYL the vinylation of aliphatic alcohols. ETHERS OF PENTAERYTHERSTOL The two-step process of the present invention is ad Normata Shachat, Levittown, and James J. Bagiel, Sr., mirably suited to being practiced in a continuous opera Phiadelphia, Pa., assigaors to Rohia & Haas Cort 5 tion. Illustratively, a solution of pentaerythritol and a pany, Philadelphia, Pa., a corporation of Delaware catalytic amount of base in water is saturated with acety No Drawing. Filed Apr. 21, 1961, Ser. No. 104,551 lene under pressure at 0°-25°C. in a suitable reactor. The 2 Claims. (C.260-6E5) base may suitably be selected from sodium and potassium This invention deals with the divinyl and tetravinyl O hydroxides and alkoxides (preferably methoxides). The ethers of pentaerythritol, as new compositions of matter, mixture is then pumped continuously under a pressure Suf and as the products of a new process for preparing them. ficient to prevent the formation of a gas phase through a Vinylation processes are well known in which the gen reaction zone which is held at the reaction temperature eral modus operandi is to mix a substance to be vinylated (130°-200° C.) with acetylene, an acetylene solvent, a suitable catalyst, and 5 After a holding time of from 1 to 20 minutes, the reac reacting the mixture under appropriate conditions of ten tion mixture is passed from the reaction Zone through a . perature and pressure. Examples of such processes are pressure release valve, and any excess acetylene gas which the vinylation of alcohols, as by the method disclosed in is evolved is recycled. The liquid effluent settles into two U.S. Patent 2,969,395, and the vinylation of glycerol, as layers. The lower aqueous layer is drawn off and directed by the method disclosed in U.S. Patent 2,969,400. 20 into the reactor for reuse in the aqueous vinylation stage In these and related prior art vinylation processes a crit of the process. The upper layer, which consists of the ical requirement is the use of an organic solvent for partial vinylation products, is dried over a Suitable drying acetylene. It is for this reason that attempts to apply agent, treated with a catalytic amount of base, saturated these prior methods to the vinylation of pentaerythritol with acetylene at a low temperature to maintain a liquid have failed. 25 mixture and led to a second reaction Zone at 130-200 Pentaerythritol is a high melting solid (M.P. 256-265 C. This second stage of the process is very much like C.) known to be essentially insoluble in most organic the general procedure described in U.S. Patent 2,969,395. solvents. One of the requirements for a solvent in the The products of complete vinylation obtained from this vinylation reaction is that it be inert to acetylene at vinyla second stage are obtained and are purified by such con tion temperatures (130-200 C.). Another requirement is 30 ventional techniques as distillation, crystallization, etc. that the solvent be stable with respect to the base that is Optionally, in the continuous process, an auxiliary, employed as a catalyst for the reaction. The problem water-miscible, good acetylene solvent may be included in has been that pentaerythritol is only slightly soluble in the original reaction mixture to increase the amount of organic solvents which meet these two requirements. It absorbed acetylene which enters into the reaction. An has, therefore, hitherto been impossible to vinylate pen 35 other alternative to the procedure described above is to taerythtritol successfully because of the difficulty in get saturate the pentaerythritol solution with acetylene, and to ting sizable quantities of it to go into solution. lead it and an aqueous solution of the catalyst to the We have now discovered that it is possible to Solve this reactor in individual streams. Still another option is to problem, with surprising success, by performing the cat introduce all three components, the pentaerythritol, the alytic vinylation of pentaerythritol with the use of an 40 catalyst and the acetylene individually into the reaction aqueous base as the solvent. An alcoholic base, instead Zone as aqueous solutions. of an aqueous base, may be used also. However, an alco If desired, it is of course unnecessary to proceed through holic base leads to an undesirable side reaction; namely, the second stage of the process. If a partially vinylated formation of the vinyl ether of the alcohol solvent. product, such as the divinyl ether of pentaerythritol, is de Illustratively, at temperature of about 150 C., acety sired, it can be produced in substantial quantities in this lene was absorbed by the aqueous mixture at such a good way. This divinyl ether is a highly useful polyfunctional rate that, during a period of about five hours and under cross-linking agent, and this ready means for its prepara 200-400 p.s.i.g. acetylene pressure, between 50 and 75% tion and isolation is a valuable improvement in the art. of the pentaerythritol was converted to a distillable liquid it may be stated that all of the polyvinyloxy compounds mixture of partial vinylation products. (If convenient, 50 which are provided by the present invention are useful greater pressures up to about 2000 p.s.i.g. could be as cross-linking agents for ion-exchange resins and textiles used to good advantage in the practice of this invention.) (cellulose cross-linkers). Typical methods for their prepa The mixture of liquid products from this aqueous vinyla ration will be found in the following examples. tion was then treated with acetylene and a catalytic amount of base in the conventional manner (i.e. using an organic Example I acetylene solvent) to effect complete vinylation. The final result was a mixture composed of about 70% tetravinyl A solution consisting of 880 parts of HO, 120 parts of ether of pentaerythritol, 30% of 2-methyl-5,5-divinyloxy potassium hydroxide and 410 parts of pentaerythritol was methyl-1,3-dioxane, and less than 1% of the bis-acetal. placed in a 3-l., mechanically stirred autoclave. The The tetravinyl ether was readily separated from the mix 60 system was pressure tested with nitrogen flushed with ture by crystallization. nitrogen, and then flushed with acetylene. The reaction The novelty of using water as a solvent in this reac mixture was heated at 145-160° C. for five hours while tion will be readily apparent since it is well known that acetylene was introduced at a pressure of 300-470 lbs./ simple monohydric alcohols, such as methanol, n-butanol, sq. in. The excess acetylene was vented and the crude isopropanol, etc., do not undergo vinylation in the pres reaction mixture (1682 parts) which separated neatly 3,165, 556 f ea into two layers was removed from the reactor. The the pure compound exhibited absorption bands at 1634, upper organic layer was separated and the aqueous layer 1615, 1197 and 1082 cm.-1 which are attributable to vinyl was washed several times with ether. The ether washes ether functions. were combined with the organic layer and the ether was Analysis.--Calculated for CH2O: C, 64.98; H, 8.39; stripped at atmospheric pressure. Flash distillation of Inol. wt., 240.3; hydrolyzable aldehyde, 16.6 meg./g. the product mixture to a pot temperature of 159 C. at Found: C, 64.72; H, 8.28; mol. wt. (ebuilioscopic in 0.44 mm. afforded 499 parts of a liquid mixture of partial acetone), 251; hydrolyzable aldehyde (hydroxylamine vinylation products, and 201 parts of a brown glossy hydrachloride method), 16.5 meq/g. solid residue which was partially soluble in water. Re A mole of the tetravinyl ether cleanly absorbed four distillation of the liquid distillate afforded 250 parts of 0. Iinoles of hydrogen over a platinum oxide catalyst at a liquid mixture of partial vinylation products, boiling room temperature and atmospheric pressure. range 65° C./0.15 mm. to 93° C./0.13 mm., n25 1.4716 As an unequivocal structure proof of the main prod to 1.4781, hydrolyzable aldehyde (hydroxylamine hydro ucts of the complete vinylation of pentaerythritol, the fol chloride method), 11.9 to 12.9 med./g., which could not lowing reactions were performed. A mixture of the be separated readily by distillation, and 122 parts of the 5 completely vinylated products of pentaerythritol was divinyl ether of pentaerythritol, B.P. 99.5-100.5 examined by infrared spectroscopy and vapor phase chro C./0.16-0.28 mm. The divinyl ether of pentaerythritol matography. The infrared spectrum indicated the com was a colorless crystalline solid which could be recrystal plete absence of a hydroxyl function and the chromato lized easily from hydrocarbon solvents such as petroleum gran showed the presence of three components, one in ether, cyclohexane, etc., M.P. 63-64 C. The infrared 20 approximately 70% (previously shown to be the tetra spectrum of the compound showed strong absorption vinyl ether of pentaerythritol), one in approximately bands at 3520 and 1050 cm., which may be ascribed to 30% and the other in trace amounts. primary hydroxyl functions, and at 1628, 1614, 1192 and Analysis.-Found: hydrolyzable aldehyde (hydroxyl 1082 cm., which indicate the presence of vinyl ether amine hydrochloride method), 13.4 med./g.; vinyl ether groupS. 25 (iodine method), 12.8 meg/g.; hydroxyl number, 25. Analysis.-Calculated for CHO: C, 57.43; H, 8.57; The mixture (52.1 parts) was completely hydrogenated vinyl ether, 10.6 meq/g.; hydroxyl number, 596.

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