.Oct. 15, ‘1946. VF. J. METZGER 2,409,441 ' PRODUCTION OF GLYCOLS Filed Ilay '1, 194: // WITHDR F/q 1 4%,,” 6 Patented Oct. 15, 1946 2,409,441 UNITED STATES PATENT OFFICE 2,409,441 PRODUCTION OF GLYCOLS Floyd J. Metzger, New York, N. Y., assignor, by mesne assignments, to U. S. Industrial Chemi cals, Inc., New York, N. Y., a corporation of Delaware ‘' Application May 7, 1943, Serial No. 486,057 3 Claims. (Cl. 260-635) ,1 2 p This invention relates to the recovery of glycols from solutions resulting from the hydration of aqueous solutions of ole?n oxides in the presence of an acid catalyst and particularly to the elimi nation of complex compounds of the glycol with the acid which are formed during the hydration. As an example of the application of the in vention, it will be described with reference to the production of ethylene glycol by hydration of pipes and valves and by depositing on heating coils may interiere with the transfer 01 heat. Frequent shut-downs are required to remove the salt, and filtration is necessary to separate the salt from the glycol. Complete separation is never possible, and some loss of glycol results. The various operations and losses add to the op erating cost. It is the object of the present invention to avoid ethylene oxide as set forth in the patent to 10 the di?iculties mentioned and to afford a simple, Frederick R. Balcar No. 2,135,271. The same procedure may be utilized, however, in the pro duction of other glycols. In the Balcar procedure, ethylene oxide is dis e?lcient and economical procedure whereby the glycol can be recovered without resort to the complicated treatment hereinbefore described. Another object of the invention is the provision solved in water containing an acid hydration 15 of a satisfactory procedure whereby both free acid and combined acid are easily separated from the glycol solution, which may be evaporated and dis tion. The solution is subjected to heating for a tilled, if necessary, without the disadvantage of period of about thirty minutes at a sulliciently salt deposits during the operation. catalyst, preferably sulphuric acid in the pro portion of about 1/2% of the weight of .the solu elevated temperature to convert the ethylene 20 Other objects and advantages of the invention oxide to ethylene glycol. A temperature of about will be apparent as it is better understood by 30°~40° C. is usually employed. reference to the following speci?cation and ac The continuous production of ethylene glycol companying drawing, which illustrates diagram by the procedure described produces an aqueous matically an apparatus suitable for the practice solution of glycol containing the acid used as 25 of the invention. the catalyst. The solution is continuously with I have discovered that the complex compound drawn from the conversion chamber. The re of glycol with an acid, which is produced during covery of the glycol from the solution presents the hydration of aqueous solutions of an ole?n considerable di?iculty. Some of the acid catalyst oxide and is not amenable to simple neutraliza is present as such in the solution. The re 30 tion with an alkali, can be broken down and that mainder is combined in some manner, not fully the acid thus released can be separated, together known, with the glycol. It cannot be titrated as with free acid originally present, by the simple free acid and is not precipitated by the addition procedure hereinafter described‘. The desired re of barium chloride. , sult is accomplished by subjecting the glycol solu Owing to the presence of the combined acid, it . .1 tion to an anion adsorbing resin of which several has been necessary to follow a complicated and types are available. Such resins have been used expensive method to remove the acid from the heretofore to separate free acids from solutions, glycol solution. This involves treating the solu but it has not been known that the combina tion with an excess of caustic soda and heating tion of glycol with an acid in the form herein at an elevated temperature for a considerable 40 described is amenable to the anion adsorption period. Thereafter, the excess alkali must be neutralized with additional acid. The consump tion of alkali and acid is considerable. The solution, then containing sodium sulphate, activity of resins.. In carrying out the invention, I may use any resin of the anion adsorption type. Several are known, and it will su?lce to mention two which is evaporated in a triple-e?ect evaporator to re 45 are commercially available. These resins are in move the water in stages and is ?nally treated general the product of condensation of organic in a vacuum distillation apparatus to vaporize amines or similar basic materials with formalde and recondense the glycol. As evaporation pro hyde. One known as “Anex” is believed to be a ceeds, the concentration of sodium sulphate in melamine resin, since it contains about 33% of creases to the limit of solubility, after which it 50 nitrogen. The other, “Amberlite 1R-4” is the precipitates as solid sodium sulphate. The salt product‘of condensation of aromatic amines such is deposited in increasing amounts in the latter as aniline with formaldehyde. The invention is stages of evaporation, and ?nally in the vacuum not limited to the use of these particular prod distillation equipment. This, of course, is un ucts, as any resin having anion adsorption activ desirable because it may result in stoppage of 55 ity can be used to accomplish the purpose. 2,409,441 4 For the purpose of the invention, a simple ap paratus may be used. It may consist of a col umn 5 in which a deep bed 8 of the resin is sup ported. The resin may be in the form of par ticles ranging in size from 16 to 50 mesh, al though larger or smaller particles may be used. A pipe 1 is connected to the bottom of the col umn to permit the introduction of the glycol s0 luticn which escapes through a pipe 9 at the top. Suitable connections i0 and H may be provided _ to permit the introduction of water and the re The procedure avoids much of the expense heretofore incident to the recovery of glycol from solutions in which it is formed by catalytic hy dration. It is'simple and more efficient, involv ing only the use of inexpensive equipment. Various changes may be made in the appa ratus without departing from the invention or sacrificing. the advantages thereof. ‘ I claim: ' 1. The method of converting an ole?n oxide to the corresponding glycol, which comprises dis solving the ole?n oxide in water containing an acid hydration catalyst that forms a non-titrat generation solution when necessary. ‘The glycol solution is introduced and caused to flow through the bed of resin at a. relatively able acid complex with the'glycol, maintaining low rate such that when the solution leaves the 15 the resulting solution under conditions favorable apparatus it will contain no free or combined for hydration of the dissolved olefin oxide to the acid. Operation is preferably at normal room corresponding glycol, and subsequently treating temperature, 1. e., 70° F., although the tempera the glycol solution with an anion adsorbing resin ture is not critical except with reference to ele to break down the glycol-acid complex with lib vated temperatures. When the resin has lost its 20 eration of the'acid and to remove the free acid adsorption power as shown by the appearance of from the solution. acid in the eiiluent, it may be regenerated by 2. The method of liberating the acid from the ?rst ?ushing the bed with water to eliminate the non-titratable glycol-acid complex formed dur glycol solution and then introducing an aqueous ing the hydration of an aqueous solution of the solution of sodium carbonate, preferably 2%-4% 25 corresponding ole?n oxide in the presence of an by weight. The resin‘ is then rinsed with water acid hydration catalyst that forms such a com and is ready _for further use. plex with the glycol and removing the free acid The glycol solution, free from acid, and par from the resulting glycol solution, which com ticularly acid'in combination with the glycol, may prises passing the aqueous glycol solution through be delivered to the multiple eifect evaporator and, 30 a bed of anion adsorbing resin. after concentration, may be distilled to recover 3. The method of liberating sulphuric acid the glycol. Since no alkali is introduced, the so from the non-titratable ethylene glycol-sulphuric lution is free from sodium sulphate and conse acid complex present in the aqueous solution requently no di?iculty is met with deposits in the sulting from the hydration of ethylene oxide in evaporating and distillation system. Moreover, 35 the presence of sulphuric acid, which comprises since the solution is free from acid and salt, a passing the aqueous solution of ethylene glycol marketable glycol may be obtained merely by through a bed of an anion adsorbing resin. evaporation and without the necessary step of distillation. FLOYD J. METZGER.