DE1595514A1 - Improved method for drying ion exchange resins - Google Patents

Description

1 BERLIN 33 .... "8" MtJtHH-IEN

Auguste-Viktoria-Strasse 66 Dr.-liig. HANS RUSCHKE Pienzenauer Strasse 2

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Viktoria Strasse 66

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T.Wo »:« m / »™ ä ^r _A ». - Telephone: 0811 / «« «

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Berlin West 74 94 Munich 682 77

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? Ä Straße 42 ^, Kas.e Leopo.d.tr, B.

Account 32 7608 Account 89 515

Telegram address: Telegram address:

Quadrature Berlin Quadrature Munich

D 1431 The Dow Chemical Company, Midland, Michigan, V.St _o A <

Improved method for drying ion exchange resins

The invention "relates to an improved method for Regeneration of ion exchange resins that are used as dehydrating agents «

Ion-exchange resin dehydrating agent which have been loaded with water, can be regenerated by passing a dry stream of hot air, usually at a temperature in the range of 100 - as long as through leads 150 ⁰ C by the resin until the sorbed water removed is · The long periods necessary to dry the resin and the amount of relatively expensive equipment required are significant disadvantages of this process.

It has now been found, and upon which the basis of the present invention is based, that evaporation accelerates

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and effectively performed · v / ground, by the existence of an azeotropic mixture-forming halogenated KohlenwasserstoffSo It is desirable that the azeotropic mixture formed a boiling point at atmospheric pressure of 50 - has 165 ⁰ C "Preferably, boiling the azeotropic mixture at a temperature of 85 - 125 ° C "Azeotropic mixtures with the desired boiling points are formed by the water of a moist ion exchange resin and one or more of the following halogenated hydrocarbons: trichlorethylene, perchlorethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1, 1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, carbon tetrachloride, ethylene dichloride, propylene dichloride, chloroform and 1,2,3-trichloropropane.

The process of the present invention is applicable to virtually all ion exchange resins. Because of the higher However, in durability properties, it is desirable to use a cation exchange resin. Preferably that is resin used a sulfonated styrene-divinylbenzene-JWisahpolymerisat and in particular there are sulfonated resins with an alkali hydroxide or carbonate have been neutralized

In the practice of the invention, the mixture of the ion exchanger loaded with water - resin and the halogenated hydrocarbon in one Temperature: at or above the boiling point of the azeotropic

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pen mixture held, and the azeotropic mixture is distilled off an amount of the halogenated hydrocarbon, which is sufficient to form at least one azeotropic mixture with the water to be removed is used, and the distillation operation continues until the Ion exchange resin has been dried to the desired degree «The azeotropic distillate can be condensed and the halogenated hydrocarbon can be recovered for further use by separating the essentially immiscible water and halogenated hydrocarbon layers of the condensate «

The halogenated hydrocarbons can with the are brought into contact with water-laden ion exchange resin either by passing through them heated Vapors of the halogenated hydrocarbon in contact with the resin or by immersing the resin in the liquid halogenated hydrocarbons in feathers case the water present is removed by maintaining of the system at or above the boiling point of the azeotropic oemigiches in order to effect an azeotropic distillation. When the halogenated hydrocarbon heated bowls in contact with the ion exchange resin laden with water · the to Azeotropic distillation of the necessary temperature can be achieved by satisfying the system can be heated for a long time, to a fine temperature

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or above the azeotropic boiling point. on the other hand the mixture of the halogenated hydrocarbon and the resin laden with water can also be achieved by external measures be heated to the required azeotropic distillation temperature »As an example of the latter procedure the ion exchange resin to be dried can be contained in a column or bed which is heated with the help of an electrical heating tape.

As indicated above, the halogenated hydrocarbon used in the process of the present invention is advantageously selected so that an azeotropic mixture of halogenated hydrocarbon and water with a boiling point between about 50 and 165 ⁰ C results. while higher-boiling azeotropic mixtures can cause the resin to degrade. The process according to the invention is preferably carried out at atmospheric or practically atmospheric pressure; however, for the sake of simplicity, superatmospheric prints can also be used.

The amount of halogenated hydrocarbon used depends on the amount of water in the resin to be dried on the amount of water * to be removed and on the type and shape of the ion exchange resin. Maximum drying is achieved when the azeotropic distillation is carried out as indicated by changing the temperature

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stops, in which the distillate is absent _(Engl comes off) and by the absence of a water layer in the condensates

Each ion-exchange resin which is used as a dehydrating agent or in a process that leads to a sorption of water by the resin can be regenerated by the inventive process, provided that the resin compared to the halogenate hydrocarbon is inert under the drying conditions employed ₀

The following examples illustrate the invention:

example 1

A section of glass tube with an inner diameter of 15 »8 mm was used to make a dry column. This column was up to a height of 76.3 cm, corresponding to 138 g, with a dry sulfonated styrene-divinylbenzene copolymer containing 8% by weight of divinylbenzene, in the form of spherical particles with an average diameter of 0.3 - 0.84 mm filled. Wet methylene chloride containing 0.144% v / water was passed down this column; at a flow rate of 20.4 ml / min / cm _β The effluent from the bottom of the column contained about 0.0002 wt "~ # water, a chop-off efficiency of about 99" 8 ° / o öntfjprioht "This flow through the; The column was continued until the water content of the drain was about 0.001

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Wt _o - $ rise, at which time the flow is interrupted wurdeο It was calculated that the total accounted for at this time of water removed 14.9 parts water per 100 parts by weight of the dry resin, "

A small evaporator vessel was attached to the bottom of the drying column. A quantity of about 500 ml perchlorethylene was added to this vessel and heated to boiling point therein, the vapors moving up through the dewatering column. These vapors heated the resin bed to such a high level Temperature at which the Viasser could be removed in the form of vapors of an azeotropic mixture of water and perchlorethylene, which were discharged through the top of the column. This procedure was 4 hours long _o to the absence of a Wasseröchicht in the condensate;?! continued, which indicated the completion of the formation of the azeotropic mixture "The evaporator vessel is then removed and the capacity of the dried resin was again determined by wet methylene chloride sent through the column, until the water content in the effluent to 0.001 wt. ~ $> increased The capacity after perchlorethylene vapor regeneration was found to be about 15.6 parts of water removed per 100 parts by weight of dry resin *

This procedure was repeated several times using the same resin with similar ones Results as shown by measured values based on comparable capacities after each regeneration «

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In a further experiment, the resin drying column was wrapped on the outside with an electrical heating tape, and the column was heated gently during the regeneration cycle This reduced the regeneration time and resulted in a lower pressure build-up in the evaporator under more complete conditions Regeneration of the resin that takes place during a period of 1.5 hours was completed,

Similarly, other halogenated hydrocarbons, such as trichlorethylene and methyl chloroform, have been used to regenerate water-laden ion exchange resin dehydrating agents by the procedure of the above example. These halogenated hydrocarbons have been found to be similarly effective in removing water from the dehydrating agent, _etc.

The sodium and hydrogen forms of the resin found in The above example could be used with similar results following the procedure described above to be used,

Example 2

The procedure of Example 1 was followed except that the wet ion exchange resin was placed in a vessel containing trichlorethylene. This vessel containing the wet resin immersed in the halogenated hydrocarbon was then heated to the boiling point of the azeotropic trichlorethylene mixture and the vapors of the azeotropic mixture of water and trichlorethylene were fed to a cooling column. After about 1.5 hrs _e the resin was removed and regenerated as fully

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found to be re-used as a dehydrating agent "

In summary, it should be noted that the method of this invention is not dependent on the solubility of water in the halogenated hydrocarbon « On the contrary, the invention uses a halogenated hydrocarbon which is an azeotropic mixture with low Able to form boiling point, which is essentially immiscible in two on subsequent condensation Separates components. In this way, the solubility of the components present is important for the process of the invention, doh, water and halogenated hydrocarbon, neither necessary yet desirable

Comparison search:

For purposes of comparison, two samples were dried of loaded ion exchange resin with water of the same weight after veüschiedsnen methods, even by regeneration under Durohleiten hot air through it, other mm to & he method of yorliegendj ^ ö Erf jyn-

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Claims (1)

D 1431 15955U Patent claims: 1o method for drying an ion exchange resin, evaporation of the adsorbed water from the resin into a heated atmosphere thereby taking place characterized in that the evaporation in the presence of an azeotropic mixture forming halogenated hydrocarbon performs ,, 2ο The method according to claim 1, characterized in that a halogenated hydrocarbon is used which forms an azeotropic mixture with a boiling point of 50-165 ⁰ O at atmospheric pressure. 3ο üferfahren according to claim 2, characterized in that the aqueous azeotropic mixture boils ^{at a temperature of 85-125 0 G.} 4 * Process according to one of the preceding claims, characterized in that the halogenated hydrocarbon Trichlorethylene, perchlorethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, , 1,1,2,2-tetrachloroethane, carbon tetrachloride, ethylene dichloride, Propylene dichloride, chloroform, 1,2,3 ~ trichloropropane or a mixture of two or more of these compounds is used. 5. Method according to one of the preceding claims, BATH ORIGINAL 009818/1573 15955H characterized in that the ion to be dried exchange resin a sulfonated styrene-divinylbenzene copolymer used. 6. The method according to claim 5 »characterized in that the sulfonated resin is neutralized with an alkali hydroxide or carbonate« D 1431 0 09818/1673