IL24367A - Permselectve membranes and process of making same - Google Patents

Abstract

1,161,513. Permselective membranes. ISRAEL, STATE OF. and A. SUSZER. 23 Sept., 1966 [24 Sept., 1965], No. 42490/66. Heading B5B. [Also in Divisions C3 and D2] Permselective membranes are made by bonding organic fibre-active molecules containing acidic or basic groups to a cellulosic sheet. The bonding comprises ether or ester links. The membranes exhibit permselectivity in a broad pH range. The permselectivity exceeds 14 mV in a cell containing N/10 to N/20 KCI, and the resistance < 20 ohm/cm<SP>2</SP>. Links are formed by (a) partially esterifying the sheet with isatoic anhydride or a derivative thereof, diazotizing the resultant anthranoyl ester of cellulose, and coupling an agent containing acidic or basic groups; (b) by the interaction of the cellulosic sheet with a halogenated N- containing heterocyclic compound which may contain at least one sulphonic acid group, or at least one basic group, which may be alkylated; (c) etherification of the cellulose with the dibasic salt of tris-#-sulphatoethylsulphonium inner salt; or (d) etherification with propane or butane sultone. The cellulosic sheet may be of regenerated cellulose or partially hydrolysed cellulose esters, e.g. cellulose acetate.

Description

0 ΰ 3 η I η η ι π D π π πριπ 1 VE MEMBRANES and State of Israel Arise It is an object of the present invention to provide novel permselective It is a further object of the present invention to provide permselective membranes for use in the desalination of It is yet a further object of the present invention to provide a process for the production of permselective Other and further objects of the present invention will become apparent According to the present invention there is provided a novel process for the production of permselective The novel membranes according to the present invention are characterized by having attractive electrochemical and mechanical properties for electrodialytic water The production of membranes according to the invention is inexpensive and quite and the products give very good permselectivity in eleetrodialysis cell The novel membranes according to the present invention are prepared from preferably cellulosic sheet such as parchmentized foils and films of regenerated cellulose as sheets of partially cellulose esters such as cellulose acetate and the Such cellulosic sheet materials are according to the present to chemical resulting organic in chemical bonding to the cellulosic sheet of pendant File 12 molecules which contain optionally one or more acidic or functional groups which convert the sheet into a According to a broad aspect of the there is provided a process for making permselective membranes which comprises substantially permanently bonding via etheric or ester links organic molecules containing acidic or basic functional group to a cellulosic sheet thus imparting to the resulting membrane in the pH range of The permselectivity exceeds about 14mV in a cell containing to potassium the permselective membranes exhibit electrical resistances less than about 20 According to a further aspect of the there is provided a permselective membrane comprising a cellulosic sheet to which there are bonded by ester or etheric organic molecules containing therein acidic or basic functional According to one embodiment of the invention the cellulosic sheet is interacted with an anhydride such for isatoic or a derivative chemically bonding same to a hydroxyl group of the cellulosic material by an ester linkage leaving a free amine function for or for further This amine is then diazotized by conventional methods and finally coupled with an acidic compound such as a sulphonic File 12435 According to a second embodiment of this invention the attachment of the permselectivity producing compound may be accomplished by first reacting a trichlorotriazine compound with an acidic or basic such as a sulphonic containing or an containing compound to produce a dichlorotriazine derivative and this reaction product is then interacted with the cellulosic sheet material to produce a permselective Other heterocyclic compounds containing at least one nitrogen atom and containing bonds can be used in place of the triazine For example halogen stituted halogen substituted amides of quinoxaline carboxylic acids can be used and suitable functional groups can be attached as set According to another molecules can be attached to the cellulosic material by an ether link and these will be exemplified by compounds that contain reactive sulfonium moieties or sultone such as inner According to another mode of producing permselective the cellulosic sheet such as is first partially esterified with isatoic anhydride or a derivative the resulting anthranoyl ester of cellulose is and the diazotized intermediate is reacted with a compound having the aforementioned basic or acid functional Other anhydrides that may File 12435 disul anhydride and Amongst compounds suitable for reaction with the diazo ized intermediate there may be mentioned phenol sulphonic dimethyl azoic containing ionic functional groups rendering the sheet Wherever the basic functional groups are not of the they may be optionally alkylated to increase their of A better and fuller understanding of the present invention be had by referring to the following which are to be construed in a A sheet of cellophane of about mm thickness was immersed for about 2 hours in a 10 per cent by weight aqueous solution of at a pH of between and and the steadily agitated solution was maintained at a temperatures between At the end of this period the of the solution was adjusted by the addition of an alkali as sodium sodium sodium phosphate or sodium to a pH of between 8 and 12 and the sheet was maintained in the solution for an additional 3 After rinsing with warm and subsequently with cold there waa a mechanically strong permselective The electrical resistance of this membrane varied between about and and its permselectivity between and aqueous asium chloride was It is assumed that the product has a structure as ors not bound by but the invention no validity of this proposed Example 2s Parchment paper of about mm thickness was constant agitation immersed under during 6 hours in 20 prepared percent by weight aqueous solution of a reacting tetrachloropyrimidine and the monoazoic dye of the following chemical formula at temperature and at a pH of between and After this the pH was adjusted to 11 12 b the addition of an as in Example and the paper was maintained in the solution for a further hours at After this the membrane was rinsed in Its electrical resistance was between and the permselectivlty was m measured in a cell containing and by the membrane temperature Kraft paper of about mm thickness was maintained during 2 hours in 15 per cent by weight aqueous solution of disodiura salt sulfonium inner sal at a of at The sheet was subsequently dried room temperature without prior rinsing and introduced further into pe cent aqueous sodium hydroxide solution hour eady at a temperature of about There was obtained an membrane which had a resistance o to and a permselectivity of It is assumed that the structure of the membrane may be represented as Example A cellophane sheet of about mm thickness maintained during 2 hours with constant agitation in an aqueous per cent by weight solution of sulfaminyl of the following at a pH of to After this the pH of the solution was adjusted by the addition of as in Example to pH to and the sheet was left in the solution for a further Afte rinsing and drying the shee 20 minutes with percent aqueous sodium for pressed out and immersed 2 hours with e constant agitation in a 10 per cent by weight solution of propane su The sheet was rinsed with warm and cold and There was obtained a membrane having a resistance of 2 about ohm em and a permselectivity of between and potassium Example Parchment paper of about thickness was for maintained 4 hours in a 5 cent by weigh aqueous solution of the derivative of trisulfonic The agitated solution was maintained at a temperature between and at a pH of to After this period the sheet was without into a pe cent by weigh aqueous solution of sodium carbonate containing 2 per cent by weigh sodium and in this solution TfiyfTrfg 8 hours at After rinsing warm and a mechanically strong membrane was The electrical resistance of this membrane about ohm cm its permselectivity between and potassium chloride bein Example A foil of cellophane of mm thickness was esterified with isatoic anhydride according to known The anthranoylated having a nitrogen content of about to per cent by was diazotized by immersion 1 hour at 0 in a per cent s of sodium nitrite acidified towards with hydrochloric The sheet was rinsed with icewater and coupling with for disulfonic acid was effected by immersion 3 hours in a 2 per cent by weight alkaline solution of this compound at There was obtained a membrane having an electrical resistance and a permselectivity of between and aqueous potassium A proposed structure of the product can indicated schematically as E3cample A sheet of diazotized anthranoylated cellophane was prepared as in Example and this was coupled immersion in with dimethyl aniline by 2 cent for by weight solution of this compound 3 hours at a of at a temperature of The sheet was rinsed and zed in a 25 per alcoholic solution of methyl There was obtained an anionic membrane having a permselectivity of measured as in the preceding and a resistance of the Without to compound the permselectivity is Example A sheet of diazotized was prepared as set Example 6 and coupled with the monoazo dye of the in an There was obtained a cationic 2 membrane of about ohmcm resistance and permselectivity of measured as in the preceding A sheet of cellophane of about mm thickness as set out in Example The sheet was diazotized 1 hour at with acidic solution of sodium After rinsing with icewater the sheet was immersed i an alkaline 2 per cent alkaline of trisulfonie acid for 3 hours at a temperature of There was obtained a ca ionic membrane which had a resistance of 1 and a of as in the preceding insufficientOCRQuality

Claims (8)

1. P.A.24361 File 12 5 29.1.69 WHAT i≤ CLAIM IS: 1· A process for producing ion-permselective membranes, exhibiting permselectivity in the range of pH 1 to 14, which comprises substantially permanently bonding, via ester or ether links, organic molecules containing acidic or basic functional groups to a cellulosic sheet, converting this into the desired membrane.

2. A process according to Claim 1, wherein said permselectivity exceeds about 14 saV in a cell containing N/10 to N/20 potassium chloride.

3. 2he process according to Claim 1, wherein said penaselective membranes exhibit electrical resistances of less than about 20 ohms/cm .

4. A process according to Claim 1, wherein said ester links are prepared by the steps of partially esterifying said cellulosic sheet with isatoic anhydride or a derivative thereof, diazotizing the so obtained ant ranoyl ester of cellulose, and coupling said diazotiaed ester product with a coupling agent, said agent containing acidic or basic groups.

5. A process according to Claim 4» wherein the derivatives are sulfoisatoic anhydride, 3-(4 sulfophenylazo)-isatoic anhydride, or 3-(l,4,-disulfophenylazo) isatoic anhydride.

6. A process according to Claim 1, wherein said ester link is obtained by the interaction of the cellulosie sheet with a halogenated nitrogen-containing heterocyclic? compound.

7. A process according to Claim 6 wherein said heter-°" J¾fcyelic compound is selected from the group consisting of chlorinated s-triazine, a chlorinated pyrimidine compound, and a substituted amide of 2t3^icliloro-quinoxaline-6-car- boxylic acid.

8. A process according to Claims 6 or 7, wherei the P.A. No. 24367 Pile No. 12435/6 Date t 13.V.1969 14. A permselective membrane comprising a cellulosic sheet to which there are bonded, by ester or etheric linkages, organic molecules containing acidic or basic functional groups. 15· A permselective membrane consisting of a cellulose sheet to which there are bonded molecules of an ester of anthranilic acid or of a derivative thereof, which contain basic or acidic functional groups. l6. A permselective membrane comprising a cellulosic sheet to which there are bonded via etheric links a plurality of halogenated nitrogen containing heterocyclic molecules, said molecules being substituted by acidic or basic functional groups. 17· Permselective membranes substantially as hereinbefore described. 18. Permselective membranes whenever obtained by a process as claimed in any of the preceding process claims. DATED THIS 23rd day of SEPTEMBER 1965.