US2892823A

US2892823A - Modified water-soluble polyacrylamides and method of making same

Info

Publication number: US2892823A
Application number: US640069A
Authority: US
Inventors: Fred E Boettner; Warren D Niederhauser
Original assignee: Rohm and Haas Co
Current assignee: Rohm and Haas Co
Priority date: 1957-02-14
Filing date: 1957-02-14
Publication date: 1959-06-30
Anticipated expiration: 1976-06-30
Also published as: FR1198808A; BE564743A; BE564744A; FR1198809A; GB876591A; DE1060602B; GB877956A; DE1060143B

Description

United States Patent ODIFIED WATER-SOLUBLE POLYACRYLAM- IDES AND IVIETHOD OF MAKING SAME Fred E. Boettuer, Philadelphia, Pa., and Warren D. Niederhauser, Huntsville, Ala., assignors to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Application February 14, 1957 Serial No. 640,069

17 Claims. (Cl. 260-861) This invention deals with modified water-soluble polyacrylamides as new compositions of matter. It further deals with methods for the preparation of these modified water-soluble polyacrylamides.

The modified water-soluble polyacrylamides contemplated in this invention may be represented by the following formulae:

in which X and Y are integers, M is a cation, and D is a modifying monomeric unit capable of copolymerization with methyl acrylate, to be more fully explained hereinafter.

The compounds of this invention corresponding to Formulas I and II are prepared by reacting N-methylglucamine with a modified poly(methyl acrylate) in molecular ratios in the range of from about 0.1 to 1.1 equivalents of methyl acrylate, with Formula I representing the compounds exhibiting a 1:1 ratio of stated units and Formula II representing the other ratios. The modified po1y(methyl acrylates) are to be construed to mean in the preferred embodiment any methyl acrylates that can be copolymerized with any alkyl methacrylates in which the alkyl portion contains from one to eighteen carbon atoms or any alkyl acrylates in which the alkyl portion contains from two to eighteen carbon atoms. It is also quite possible and satisfactory to modify the poly(methyl acrylates) with any other compound that readily forms a copolymer with methyl acrylate. The compounds that may be employed to modify the poly(methyl acrylates) include acrylonitrile, acrylic acid, styrene and ring-substituted styrenes containing no more than a total of 18 carbon atoms, hydroxysubstituted alkyl vinyl ethers in which one to two hydroxy groups may be attached to an alkylene chain of two to eighteen carbon atoms and in which no hydroxy group is closer to the ether oxygen than two carbon atoms, and in which, if there are two hydroxy groups, such groups are on different carbon atoms; alkanamidoalkyl vinyl ethers in which the non-vinyl portion contains from 3 to 23 carbon atoms; vinyl alkyl sulfides in which the alkyl portion contains no more than 18 carbon atoms and in which portion there may be one or two hydroxy substituents provided no hydroxy substituent is nearer to the sulfur atom than two carbons and if two P we hydroxy substituents are present they are on different carbon atoms; dialkylaminoalkyl vinyl sulfides in which the dialkyl portion attached to the amino nitrogen considered individually may contain up to about eight carbon atoms and considered collectively may form a fiveto six-membered heterocyclic amino group with the amino nitrogen atom, and in which the nitrogen atom is always tertiary and is connected to the sulfur atom by means of an alkylene group containing from two to eighteen carbon atoms; N-vinyl lactams and alkyl substituted N-vinyl lactams preferably containing from six to twenty carbon atoms; alkyl vinyl sulfones in which the alkyl portion contains up to about eighteen carbon atoms; N-vinylalkyleneureas containing from five to twelve carbon atoms; and N vinyl N aminoalkylalkyleneureas containing from seven to twenty carbon atoms. In the above monomers, the alkyl groups may exhibit any possible spatial configurations such as normal, iso, or tertiary. These alkyl groups may be acyclic or cyclic, including alkyl substituted cyclic, as long as the total carbon content conforms to the defined amount. In the hydroxy substituted compounds the hydroxy group or groups may be attached at any possible location as long as the previous definition is adhered to. In the ring substituted styrenes the substituents may occupy any possible ring location or locations and when the substituents are alkyl groups they may have any possible spatial configuration.

Typical of the monomer reactants that may be employed to modify the poly(methyl acrylates) include preferably ethyl acrylate, isopropyl acrylate, cyclopentyl acrylate, Z-ethylhexyl acrylate, decyl acrylate, dodecyl acrylate, octadecyl acrylate, methyl methacrylate, tertbutyl methacrylate, eyclohexyl methacrylate, octyl methacrylate, undecyl methacrylate, and octadecyl methacrylate. There may also be typically used acrylonitrile, acrylic acid, styrene, p-butylstyrene, p-octylstyrene, ochlorostyrene, o,p-dipropylstyrene, o-methyl-p-decylstyrene, hydroxyethyl vinyl ether, hydroxyoctyl vinyl ether, dihydroxydodecyl vinyl ether, formamidoethyl vinyl ether, butanamidodecyl vinyl ether, acetamidooctadecyl vinyl ether, butyl vinyl sulfide, hydroxybutyl vinyl sulfide, octyl vinyl sulfide, octadecyl vinyl sulfide, dimethylaminoethyl vinyl sulfide, diethylaminodecyl vinyl sulfide, morpholinopentyl vinyl sulfide, pyrrolidinyloctyl vinyl sulfide, piperidinodecyl vinyl sulfide, N-vinyI-2-pyrrolidone, Nvinyl-5-rnethyl-2-pyrrolidone, N-vinyl-4,4-diethyl-Z-pyrrolidone, N-vinyl-4-butyl-5-octyl-2-pyrrolidone, N-vinyl-6-methyl-2-piperidone, N-vinyl-6-octyl-2-piperidone, N-vinyl-2,2,6,6-tetramethyl-4-piperidone, N-vinyl- 2-oxohexarnethylenimine, N-vinyl-5,5-dimethyl 2 oxohexamethylenimine, N-vinyl 4-butyl-5-octyl-2-oxohexamethylenimine, methyl vinyl sulfone, isobutyl vinyl sulfone, tert-octyl vinyl sulfone, dodecyl vinyl sulfone, octadecyl vinyl sulfone, N-vinylethyleneurea, N-vinyltrimethyleneurea, N-vinyl-1,2-propyleneurea, N-vinylbutyleneurea, N-vinyl-N'-aminoethylethyleneurea, and N- vinyl-N-dibutylaminododecylethyleneurea. The symbol D is to be construed to mean any of the monomeric units that copolymerize with methyl acrylate. For instance, methyl methacrylate, as represented by D, would be r C-CHrand oetyl acrylate would be -CI'I-CH1 COOCH; C00C8 l7 The other methyl acrylate modifying monomeric units would have representations as D according to the above explanation.

The range of proportions of the methyl acrylate unit to the modifying monomer unit which is represented as D in the above given formula may vary within the range of about 1:1 to 12:1, as desired.

While the present reaction between N-methylglucamine and the modified polymeric methyl acrylates will occur only at the methyl acrylate portion of the copolymer, as indicated in Formulas I, II, and III, it is possible to obtain valuable products wherein N-methylglucamine is reacted with a methyl acrylate unit that has been modified by any of the modifying monomers presented heretofore. In this way it is possible to obtain modified water-soluble polyacrylamides that may have properties that vary as the modifying monomeric unit varies in kind and amount. For instance, it is possible to obtain a modified water-soluble polyacrylamide that may on drying out have enhanced stiffening characteristics not possible with unmodified water-soluble polyacrylamides. Also, it is similarly possible to incorporate other desirable properties, such as enhanced toughness, hardness, chemical resisting, water insensitivity and others, by employing a modified polymeric methyl acrylate in a way not known heretofore. It is therefore possible by the method of this invention to provide modified water-soluble polyacrylamides that have a variety of characteristics not previously achievable with the unmodified water-soluble polyacrylamides disclosed in our copending application filed on even date therewith.

Only the poly(methyl acrylates) are suitable for the reaction with N-methylglucamine and other poly(alkyl acrylates) such as the poly(ethyl acrylates), poly(butyl acrylates), and the like cannot be used for reaction with N-methylglucamine, although they may be employed as modifiers of the methyl acrylate as pointed out heretofore. Furthermore, none of the other modifying monomers set forth previously can be used for reaction with the N-methylglucamine. Only the stated poly(methyl acrylates) are suitable for reaction with the N-methylglucamine. It is not entirely certain why the excluded poly(alkyl acrylates) and all of the other modifying monomeric units do not react with N-methylglucamine in the same manner as the specific poly( methyl acrylates). It is, however, quite probable that excessive cross-linking and subsequent insolubilization occurs with the excluded compounds, a result that is highly undesirable. It is therefore necessary in order to achieve the purposes of this invention that the copolymeric reactant contain a substantial portion of methyl acrylate units in order to form the defined modified water-soluble polyacrylamides.

The integer Y will have a value that will vary according to the amounts of methyl acrylate units that are not converted into a corresponding acrylamide. The actual value of Y is relatively unimportant within the limits of the molecular ratios of methyl acrylate units and N- methylglucamine previously set forth. To further illustrate the relationship of Y to the entire molecule if two molecular equivalents of methyl acrylate are employed for each molecular equivalent of N-methylglucamine, then the value of Y will be one and if nine molecular equivalents of methyl acrylate are used for each molecular equivalent for N-methylglucamine, then Y will have a value of eight. Therefore, it is apparent that the actual value of Y will vary according to the molecular equivalents of N-methylglucamine and methyl acrylate units employed and, accordingly, Formulas II and III will so vary.

The integer X will vary generally from about 230 to 4700, but it is important that the range of X and Y be such that the product is water-soluble. The modified poly(methyl acrylate) reactants that are useful in this invention range in average value molecular weight from about 20,000 to somewhat above 400,000.

The compounds of this invention represented by Formula III are prepared by reacting N-methylglucamine and modified poly(methyl acrylate) according to the ratios of Formula II and then hydrolyzing the resultant compound with an alkaline agent having the formula MOH in which M is preferably ammonium, sodium, potassium, lithium, and the like. That is, the compounds of Formula II are in ester form, whereas the compounds of Formula III are hydrolyzed into salt form. What has been said concerning integers X and Y applies equally to the compounds of Formulas II and III. Compounds represented by Formulas I, II, and III are analogous and similarly useful for the purposes of this invention.

While all of the products of this invention as defined by Formulas I, II, and III are useful for the present purposes there, of course, may be some degrees of differences of properties in addition to the modification of properties previously referred to. For instance, generally, the higher the molecular weight of the modified polymer reactant the more N-methylglucamine is required to confer water-solubility on the product and conversely. The important consideration is that the products should be water-soluble. It is, therefore, clear that another of the objects of this invention is to prepare modified water-soluble polyacrylamides from modified waterinsoluble polymeric compounds and to thereby make products useful for many applications not available to the insoluble polymeric reactants.

It is necessary to employ in the present reaction an inert organic solvent, preferably of relatively low volatility. It is preferable that both of the reactants be substantially completely soluble or miscible with the solvent and essentially unreactive with the solvent, particularly the N-methylglucamine. An excess of solvent is frequently advantageous such as from about two to six times the approximate volume of the reactants. Useful in this respect are dimethylformamide, dimethylsulfoxide, dioxane, and the like.

Temperatures in the range of about to 155 C. are employed with a range of -145 C. preferred. There is no appreciable reaction within a reasonable time below about 110 C. Substantial reaction rates are noticed beginning about 115 C. At temperatures appreciably above C. there is the tendency to obtain undesired cross-linked insoluble products. Therefore, such higher temperatures should be avoided. Generally, when a temperature in the upper part of the defined range is used a shorter reaction time is necessary and when a temperature in the lower part of the defined range is employed a longer reaction time is required. For instance, the reaction is generally complete in about three to five hours when the upper temperature values are used, whereas the reaction may require from about 20 to 24 hours for completion when the lower temperature range is employed varying of course with variations in the modified copolymeric reactant. However, the reaction time is not essentially critical but merely reflects upon the yields obtained. The important consideration is that the reaction be conducted for a sufficient length of time to permit the formation of modified water-soluble polymeric products from the corresponding modified water-insoluble polymeric reactants. This means that the reaction should not be conducted for too short or too long a period of time, for in the former instance, insutficient water solubility will be conferred on the product to satisfy the requirements of this invention or, in the latter instance, the products which have already had sufficient water solubility conferred upon them may proceed to undesired cross-linking and concurrent insolubilization. Therefore, the standard to be used is not that of an absolute time interval but rather that period of time necessary to confer water solubility on the product and short of that time when insolubilization might occur. The products of this invention lie between these two extremes.

Yields in excess of 65 to 72% and above are consistently achieved. While all of the mechanics of the present invention are not fully understood at this time, it is believed that the reaction proceeds so unexpectedly smoothly because of an autogenous catalytic effect imparted by the polyhydroxyalkyl group of the N-methylglucamine reactant.

If it is desired to make the products of this invention represented by Formula III, it is only necessary to hydrolyze a compound of Formula II with a sufiicient amount of an alkaline agent such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, or 'the like.

It is possible, if desired, to react a product of Formula II with relatively low molecular weight amines to produce further aminated compounds. Such amines as dimethylamine, dibutylamine, N-methyl-N-propylamine, dimethylaminopropylamine, diethylaminobutylamine, and the like are useful for this purpose.

In order to isolate the product, one may pour the reaction mixture into benzene or a mixture of benzene and heptane or the like which solvent or mixture of solvents is a non-solvent for the product. The product is then filtered to separate it from the solvent or mixture of solvents. It is then desirable to remove any excess of the alkaline neutralizing agent, such as by employing a mixture of cation and anion exchange resins. The resins may be subsequently separated by filtration and the product dried if desired by conventional means, such as under reduced pressure.

The products of this invention range from white or light colored viscous masses to powders and glass-like resins. The products of this invention are valuable as aggregants for the conditioning of soil and in this respect they have activities superior to those of commercially acceptable aggregants. For instance, it is typical for products to cause aggregation to a sufiicient particle size of from 95 to above 98% of all the particles treated. These products are useful in the paper industry in wet strength applications. The present products are useful in the textile industry as whiteness retention agents and are markedly superior to the carboxymethyl cellulose agents particularly in their stability toward microorganisms. They are useful as thickeners in water base paints and they impart a variety of characteristics to the film depending on the amount and nature of the modifying monomeric compounds present. Valuable films of significant hardness, toughness, chemical resistivity, and aqueous passivity may be prepared as desired.

The compounds of this invention and the method for their preparation may be more fully understood from the following examples which are offered by Way of illustration and not by way of limitation. Parts by weight are used throughout. Example 1 There are added to a reaction vessel equipped with a stirrer and thermometer 142 parts of a dimethylformamide 25% solution of a polymer composed of 80% of methyl acrylate, and 20% of methyl methacrylate. This solution is diluted with 300 parts of dimethylformamide and there is then added 97.5 parts of N-methylglucamine. The reaction mixture is heated to 140 C. under a blanket of nitrogen until the reaction mixture becomes completely water soluble (about 4% hours). The reaction mixture is then cooled to room temperature and poured into 2500 parts of benzene to cause the product to precipitate. The precipitated polymer is cut into small pieces and allowed to soak in benzene overnight. The material is then dried under vacuum. The product is a clear glasslike resin and has a nitrogen content of 5.38% (5.39% theoretical). The product corresponds to the formula OB-CH1 30 0 CHIJ JONCH J CHAGHOHMC E2011 4.7

In a similar way there are prepared the products of this invention corresponding to the following formulae:

on. CH-CH; -CH: l ONCH: milOOCaHul and CH; -OH-OH, CH= LONCHa JOOC5H 1 Example 2 Into a reaction vessel there are added 460 parts of a dimethylformamide 20% solution of twelve parts of methyl acrylate to each part of dodecyl methacrylate. A total of 181.2 parts of N-methylglucamine and parts of dimethylformamide is added. The reaction mixture is heated under a blanket of nitrogen at to C. (three and one-half hours) until the reaction mixture becomes completely soluble in cold water. The reaction mixture is then cooled to room temperature and poured into benzene to precipitate the product. The product is filtered, washed well with heptane, soaked overnight in heptane, and finally dried under a high vacuum. The product had a nitrogen content of 5.0% (5.03% theoretical) and corresponds to the formula In like manner there are prepared the compounds of this invention corresponding to the following formulae:

I-CONCH; J LCOOCHj-CH-CIHIJ HzfCHOHMCHgOI-l 10 IH 1 CH-CH.

There is added to a reaction vessel equipped with a stirrer and thermometer 142 parts of a dimethylformarnide 25% solution of a copolymer of 80% methyl acrylate and 20% ethyl methacrylate. This solution is diluted with 300 parts of dimethylformamide and there is then added 58.5 parts of N-methylglucamine. The reaction mixture is then heated to 140 C. under a blanket of nitrogen until the mixture becomes completely water soluble (about four and one-half hours). The reaction mixture is then cooled to room temperature and poured into 2500 parts of benzene to cause precipitation of the product. The precipitated polymer is cut into small pieces and allowed to soak in benzene overnight. The material is then dried under vacuum. The product is a clear, sticky, soft resin which is soluble in water giving a viscous solution. The dried polymer has a nitrogen content of 4.6%, indicating that 73.5% of the acrylate groups present have reacted with N-methylglucamine. The product has the following structure:

it r

OBI-43H. H-CHr- The above product is dissolved in water to give an aqueous 5% solution and hydrolyzed with an excess of aqueous 40% sodium hydroxide at room temperature. A commercial grade of cation and anion exchange resins '7 is added to remove the excess sodium hydroxide. The ion exchange resin mixture is separated by filtration and the product used as a water solution. The product may be obtained by drying by conventional means under reduced pressure. The product corresponds to the following formula:

1. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a poly (methylacrylate), that has been modified by any monomeric unit that forms copolymers with methyl acrylate, with N-methylglucamine at a reaction temperature in the range of 115 to 155 C. in the presence of an inert volatile organic solvent and concluding the reaction while a water-soluble product is obtained.

2. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a poly (methylacrylate), that has been modified by any monomeric unit that forms copolymers with methyl acrylate, with N-methylglucamine in such molecular proportions that about 0.1 to 1.1 equivalents of N-methylglucamine are present for each equivalent of methyl acrylate at a reaction temperature in the range of 115 to 155 C. in the presence of an inert volatile organic solvent and concluding the reaction while a water-soluble product is obtained.

3. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a poly (methyl acrylate), that has been modified by a member from the class consisting of (1) alkyl acrylates and (2) alkyl methacrylatcs, with N-methylglucamine in such molecular proportions that about 0.1 to 1.1 equivalents of N-methylglucamine are present for each equivalent of methyl acrylate at a reaction temperature in the range of 120 to 145 C. in the presence of an inert volatile organic solvent and concluding the reaction while a watersoluble product is obtained, wherein said (1) alkyl contains from two to eighteen carbon atoms and said (2) alkyl contains one to eighteen carbon atoms.

4. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a copolymer of methyl acrylate and an alkyl methacrylate with N-methylglucamine at a reaction temperature in the range of 115 to 155 C. in the presence of an inert volatile organic solvent and concluding the reaction while a water-soluble product is obtained, wherein said alkyl group contains from one to eighteen carbon atoms.

5. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a copolymer of methyl acrylate and an alkyl acrylate with N-methylglucarnine at a reaction temperature in the range of 115 to 155 C. in the presence of an inert vol t le organic solvent and concluding the reaction while a water-soluble product is obtained, wherein said alkyl group contains from two to eighteen carbon atoms;

6. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a copolymer of methyl acrylate and an alkyl methacrylate with N-methylglucamine at a reaction temperature in the range of to 155 C. in the presence of an inert volatile organic solvent and concluding the reaction while a water-soluble product is obtained and hydrolyzing the water-soluble product with an alkaline agent, wherein said alkyl group contains from one to eighteen carbon atoms.

7. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a copolymer of methyl acrylate and an alkyl acrylate with N-methylglucamine at a reaction temperature in the range of 115 to 155 C. in the presence of an inert volatile organic solvent and concluding the reaction while a watersoluble product is obtained and hydrolyzing the watersoluble product with an alkaline agent, wherein said alkyl group contains from two to eighteen carbon atoms.

8. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a copolymer of methyl acrylate and an alkyl methacrylate having a molecular weight of 20,000 to about 400,000 with N-methylglucamine at a reaction temperature in the range of to C. in the presence of an inert volatile organic solvent and concluding the reaction while a water-soluble product is obtained and hydrolyzing the water-soluble product with an alkaline agent, wherein said alkyl group contains from one to eighteen carbon atoms.

9. A method for the preparation of a modified watersoluble polyacrylamide which comprises reacting a copolymer of methyl acrylate and an alkyl acrylate having a molecular weight of 20,000 to about 400,000 with N- methylglucamine at a reaction temperature in the range of 120 to 145 C. in the presence of an inert volatile organic solvent and concluding the reaction while a water-soluble product is obtained, wherein said alkyl group contains from two to eighteen carbon atoms.

10. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by any monomeric unit that forms copolymers with methyl acrylate and N-methylglucamine.

11. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by any monomeric unit that forms copolymers with methyl acrylate and N-methylglucamine, in which there are from 0.1 to 1.1 equivalents of N-methylglucamine for each equivalent of methyl acrylate.

12. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by any monomeric unit that forms copolymers with methyl acrylate and N-methylglucamine, in which there are from 0.1 to 1.1 equivalents of N-methylglucamine for each equivalent of methyl acrylate, said modified poly(methyl acrylate) having an average value molecular weight of about 20,000 to about 400,000.

13. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by a member from the group consisting of (1) alkyl methacrylates in which said 1) alkyl group contains from one to eighteen carbon atoms and 2) alkyl acrylates in which said (2) alkyl group contains from two to eighteen carbon atoms, and N-methylglucamine.

14. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by a member from the group consisting of (1) alkyl methacrylates in which said 1) alkyl group contains from one to eighteen carbon atoms and 2) alkyl acrylates in which said (2;) alkyl group contains from two to eighteen carbon atoms, and N-methylglucamine, in which there are from 0.1 to 1.1 equivalents of N-methylglucamine for each equivalent of methyl acrylate.

15. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by a member from the group consisting of (1) alkyl methacrylates in which said 1) alkyl group contains from one to eighteen carbon atoms and 2) alkyl acrylates in which said (2) alkyl group contains from two to eighteen carbon atoms and N-methylglucamine, in which there are from 0.1 to 1.1 equivalents of N-methylglucamine for each equivalent of methyl acrylate, said modified poly(methyl acrylate) having an average value molecular weight of about 20,000 to about 400,000.

16. A modified water-soluble polyacrylamide of poly- (methyl acrylate), that has been modified by an alkyl 10 methacrylate in which said alkyl portion contains from 1 to 18 carbon atoms, and N-methylglucamine.

17. A modified water-soluble polyacrylamine of poly- (methyl acrylate), that has been modified by an alkyl acrylate in which said alkyl portion contains from 2 to 18 carbon atoms, and N-methylglucamine.

References Cited in the file of this patent UNITED STATES PATENTS 2,744,885 De Benneville et al. May 8, 1956

Claims

1. A METHOD FOR THE PREPARATION OF A MODIFIED WATERSOLUBLE POLYACRYLAMIDE WHICH COMPRISES REACTING A POLY (METHYLACRYLATE), THAT HAS BEEN MODIFIED BY ANY MONOMERIC UNIT THAT FORMS COPOLYMERS WITH METHYL ACRYLATE, WITH N-METHYLGLUCAMINE AT A REACTION TEMPERATURE IN THE RANGE OF 115* TO 155*C. IN THE PRESENCE OF AN INERT VOLATILE ORGANIC SOLVENT AND CONCLUDING THE REACTION WHILE A WATER-SOLUBLE PRODUCT IS OBTAINED.