FR2471391A1 - STRONG CATIONIC POLYELECTROLYTES IN POWDER BASED ON ACRYLAMIDE AND QUATERNIZED OR SALIED DIMETHYLAMINOETHYL ACRYLATE AND THEIR USE FOR FLOCCULATION OF SUSPENSION OF SOLIDS AND COALESCENCE OF EMULSIONS - Google Patents

Abstract

THE INVENTION CONCERNS STRONG CATIONIC POLYELECTROLYTES, IN POWDER, BASED ON ACRYLAMIDE AND QUATERNIZED OR SALIFIED DIMETHYLAMINOETHYL ACRYLATE AND THEIR USE FOR FLOCULATION OF SOLID MATERIALS SUPENSIONS AND THE COALESCENCE OF EMULSIONS. THESE POLYELECTROLYTES ARE CHARACTERIZED BY THE FACT THAT THEY CONTAIN, IN MOLAR PROPORTIONS, MORE THAN 50 CATIONIC PATTERNS REGULARLY DISTRIBUTED ALONG THE COPOLYMER CHAINS. APPLICATION TO THE FLOCULATION OF COLLOIDAL SUSPENSIONS AND OR THE COALESCENCE OF EMULSIONS.

Description

2471.391

  The present invention relates to polyelec-

  strong cationic trolyte, powdered, based on acrylate

  mide and quaternized or salified dimethylamincethyl acrylate and their use for the flocculation of solid suspensions and the coalescence of emulsions For some years now, in the context of pollution control, cationic polyelectrolytes have been used to dewater sludge from

waste water treatment.

  Of these, acrylamide copolymers

  and high molecular weight cationic monomers.

  are highly recommended. The French patent application

  2390983 discloses cationic polyelectrolytes, in the form of

  are soluble in water based on acrylamide and acrylonitrile.

  quaternized or salified dimethylaminoethyl

  in molar proportions of 10 to 50% cationic

  uniformly distributed along the chains of copo-

  lymers and simultaneously having an intrinsic viscosity

  higher than 6 dl measured at 30 ° C. in a molar solution of sodium chloride and a measured cationicity greater than 90% of the theoretical cationicity, for

flocculation of urban sludge.

  However, for the coalescence of the emulsions and / or for the flocculation of highly hydrophilic colloidal suspensions with a high content of volatile matter and / or high zata potential, Z, such as certain sludge

  organic, mineral, biological, stabilized or digested

  However, such polyelectrolytes are unsatisfactory.

  It has now been found that polyelectrolytes

  water-soluble, strong powdered cationic compounds consisting of quaternized or salified dimethylaminoethyl acrylamide and acrylate copolymers containing in molar proportions from 50 to 99% of cationic units

  regularly distributed along the chatnes of the copolymers

  Res, simultaneously having an intrinsic viscosity greater than 6 dl measured in a molar solution g of sodium chloride at 25 ° C. and a measured rainfall greater than 94% of the theoretical cationicity, are suitable

  particularly good at the flocculation of these sludges [-

  dales with a high content of volatile

  to the floating of eollo! dales suspensions

  and the coalescence of emulsions.

  The application of the copolymers according to the invention

  with a high density of charges,

  such as in the dewatering of urban sludge

  and / or industrial, allows to reduce the doses of employment, while ensuring a satisfactory and regular walk of the installations: cake non-clogging, of

  adequate volume and dryness, thus easily handled

  ble, good sludge rates for good damping

  installations, centrifugation efficiencies always greater than 98% for

  decanters continuously, clear filtrates containing all

  less than 1 gram per liter in dry matter

  for installations equipped with band filters.

  The reactivity ratios r1 and r2 were determined for the monomer pairs: aerylamide,

  dimethylaminoethyl aerylate salified by hydrochloric acid

  drique: AAM-CHA, acrylamide-dimethylaminoacrylate

  methyl quaternized by methyl chloride: AAM-CMA, dimethylamincethyl acrylamido methacrylate quaternized by methyl chloride: AAM-CMM. The following values were obtained:

Table I

  Monomer couples Reactivity ratios r1 r2

AAM - CHA 0.80 0.55

AAM - CMA 0.72 0.66

AAM - CMM 0.20 1.75

  These determinations of responsiveness ratios -

  were performed either by the method of A.J. YEZRIELEV and Coll, Vysokomol. Soedineniya, 1969, 11 (8), 1670,

  either by the method of T. KELEN and Coll, J. Polyter.

Sci., 1977, 15, 3047-3074.

  These reactivity ratios give favorable incorporation and composition curves for the quaternized or salified dimethylaminoethyl acrylate copolymers which results in a homogeneous distribution of the cationic segments along the copolymer chains. Table II reports the molar percentages of cationic monomer present in the copolymer, the percentage of copolymer having a composition at + 10% of the desired composition.

Table II

  So we see well in the case of couples

  AAM-CMA and AAM-CHA that the copolymer composition deviates

  less than the initial composition of the monomer mixture

  res in the case of the AAM-CMM couple. The copolymers obtained from the AAM-CHA and AAM-CMA pairs therefore have a more even distribution of the cationic units.

  than those obtained from the AAM-CMM pair.

  If calculated according to T. ALFREY and C. PRICE, J. Polymer. Sci. 1947, 2, 101, the coefficients e and

  Q which respectively determine the polarity of the link

  its ethylene and the reactivity of the monomer from

  responsiveness reports, the following values are obtained:

  % molar% of copolymer having a cationic monomer composition at 10% of the desired composition

AAM - CMA AAM - CHA AAM - CMM

99 99.8 8

89 91 15.7

61.6 86.2 36.9

98.9 22.9

96.4 98.6 944

vantes: -

Table III

  A high value for the Q coefficient indi-

  that the reactivity of the monomer, that is, its tendency

  this to add to a radical is strong. But the radicals corresponding to the monomers derived from methacrylic acid are tertiary, and therefore more stable than the radicals derived from derivatives of acrylic acid;

  we ultimately get a lower reactivity.

  The copolymers according to the invention possess

  simultaneously an intrinsic viscosity always higher than

  less than 6 dl determined by conventional methods at 25 ° C in molar solution of sodium chloride and a cationicity measured greater than 94% of the cationicity

  theoretically, as we will see later, the copolymers

  corresponding to the quaternized or salified dimethylaminoethyl acrylamide-methacrylate pairs

  not at the same time these two properties.

  The theoretical cationicity of a copoly-

  mother, the number of theoretical cationic milliequivalents

  present per gram of copolymer.

  For a copolymer of x,% moles of acrylamide

  of molecular weight A and y mole% of cationic monomer

  molecular weight B, that is to say for a copoly-

  mother whose average molecular weight, M, of a pattern is

  given by the relation M = xA + yB, the theological cationicity

  is given by the formula: Ct = 10 y

M

  The measured cationicity of the copolymers according to monomers Q e

AAM 1,120 0.190

CHA 1,663 1,096

CMA 1.907 1.262

CMM 6> 804 1) 215

  the invention is determined according to a method inspired by that described in "Development of organic analytical chemistry, pharmaceutical and bromatology - JA GAUTIER and P. MALANGEAU, 17th series, page 83 - Masson et Cie, Publishers, Paris", and who consists in assaying the cationic units by means of a 0.004 M aqueous solution of an anionic surfactant, dioctylsulfosuccinate

  of sodium, in buffered water-chloroform medium, in

  that of methyl yellow. The measured cationicity is ex-

  awarded in milliequivalents per gram.

  It is found that the copolymers according to the invention

  have a measured cationicity always very

  close to the theoretical cationicity, while the copo-

  Corresponding lymers with methacrylates instead of acrylates have measured cationicities close to the theoretical cationicities only for copolymers with high content of cationic units. A measured cationicity close to the theoretical cationicity indicates a good distribution of the cationic units along the chains; indeed, when the cationic units are grouped instead of being regularly distributed, the chains tend to form balls in which the cationic units are not reached by the reagents

  dosing and no longer play their role properly.

  Table IV gives the values of visco-

  intrinsic value (5) expressed in dl, of the cationicity g

  theoretical and measured cationicity, expressed in milli-

  cationic equivalents present per gram of copolymer, for a number of homo or copolymers derived from the following monomers: AAM, CHA, CMA, CMM, CHM:

Table IV

  Monomer% molar of Cationicity Cationicity Cm in%) dl cationic measured theoretical monomer Ct g cationic Ct Cm

MSM 50 2.82 2.75 97% 46

CMM 100 4781 418 100% 4.0

CMA 100 5.1 99% 9.1

CHA 70 4.5 94.5% 14.5

CHA 100 5.4 96.9% 10.2

CHM 100 5.16 4.9 95% 4.8

ON -P- wl '

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  Experimentally, the dose of

  K, expressed in kilograms of copolymer per tonne of solids contained in the sludge

  to obtain regular and satisfactory

  no clogging or sticking of the cake in the band filters, for sludge of various origins: urban, industrial and pretreated according to different techniques: digested sludge, stabilized sludge, biological sludge, dry matter concentrations, Ms, variables and reports volatile materials on materials

  dry, Mv, between 50 and 85%.

  The concentration of solids in a sludge is determined by drying the slurry at 1050C at constant weight and is expressed in grams per 100

grams of mud.

  The volatile content of a slurry, Mv, is determined by gasification of the sludge in an oven at 575 t 250C; it is expressed in grams for

  grams of dry matter contained in the mud.

  Organic sludges are organic sludges

  hydrophilic substances from prolonged aeration of industrial and / or urban waste water:

  discards of breweries, dairies, petroleum

chemical ...

  Stabilized sludge is an organic sludge

  hydrophilic substances mainly from urban wastewater treatment plants that have

  aerobic digestion, that is, mineralized.

  We call digested sludge, organic sludge

  hydrophilic substances mainly from urban wastewater treatment plants that have

anaerobic digestion.

  Table V presents the experimental results

  levels obtained either with copolymers according to the invention or for comparison with copolymers described

  in French Patent 2,390,983, or with homopoly-

  of dimethylaminoethyl methacrylate quaternized by methyl chloride, CMM, or finally with

  homopolymers of dimethylaminoethyl acrylate quater-

  by methyl chloride, CMA.

Table V

  (1) Collage the cake on the canvas.

  Table V shows the clear superiority of the copolymers according to the invention for the dewatering of sludges with a high content of volatile matter:

  A - The use of copolymers according to the invention

  containing in molar proportions more than 50% of cationic monomers avoids any clogging phenomenon of the band filters and allows an easy detachment of the

  dry cake and suitable volume. In part-

  The copolymer contains, in molar proportions, 70% of CMA and 30% of AAM. is suitable for this type of sludge

  Nature of Sludge Stabilized Sludge Sludge -

  digested biological sludge ProvenanCe Sludge industry Food Urban A Urban B Urban D Materials 2.6% 2.4% 2.55% 4.4% dry MS Volatile materials 84.5% 74.7% 71.8% 53% Dry matter dare job._ nature K / TK / TK / TK / T of the Polynesia

% CMA 2.5. 3.5 3.4

% CMA-20% AAM 2.65 3.25 2.5

% CMA-30% AAM 5 2.25 3 2.6

% CMA-40% AAM 2.55 3.25 2.4

% CMA-50% AAM 3 3.25 2.1

% CMA-70% AAM 2.75 (1) 3.25 (1)

% CMM 6 2.9 (1) 3.4 4.8

rich in volatile matter.

  In Table VI are reported the parameters

  walking distance from a sewage treatment plant

  urban areas treating stabilized organic sludge,

  both a solids content of 2.04% and a dry matter solids ratio, Mv, of 60%, Ms and working with a CHA-AAM copolymer, 70-30, as sludge dewatering agent. This station is equipped with a double band filter whose speed

  canvas was fixed at 1 meter per minute.

Table VI

  According to Table VI, to obtain a cake of the same dryness 13.5 + 0.2 g of dry matter for

  grams of cake, the employment dose K of polyelectro-

  lytes expressed in kilograms per tonne of dry matter contained in the sludge is significantly lower for

  the polyelectrolyte 70 CHA - 30 AAM according to the invention.

  It is known that the esters of acrylic acid

  that in general and dimethylaminoethyl acrylate in particular are much more easily hydrolysable

  than the corresponding esters of methacrylic acid.

  By simply dissolving these products in water which gives a pH solution of 11, it is found that at 20 C, dimethylaminoethyl methacrylate hydrolyses very well Food Flocculation Solid Extract Flow I Ms Flow Nature Flow Rate in g of Ms m3 / hg / 100g Kg Ms / h flocculant use for 100g flocculant g / h K / T cake

  11.35 16.9 191 70% CHA- 322 1.7 13.3

% AAM

, 77 16.9 266 "522 1.95 13.5

  11.35 20.4 232 100% CHM 733.7 3.2 13.6

__3, _,. 1 _, _ 6

  little: 6% in 30 minutes, while at the same time

  % of the dimethylaminoethyl acrylate are hydrolyzed.

  At pH 5.5 - 6, the hydrolysis of dimethylaminoacrylate

  ethyl is lower, it is in one hour of 0.8% at 400C and 3.8% at 60 C, but it is still 4 to 5 times faster than that of the corresponding ester of

methacrylic acid.

  Similar results are cited in the literature on the hydrolysis of acid and acrylic acid and methacrylic acid ester polymers. Thus in the encyclopedia KIRK-OTHMER, 2nd edition, volume 13, page 344 are mentioned, among others, the works

  G. SMETS et al., J. Polymer. Sci., 1959, 41, 375-

  showing that polymers of methyl methacrylate

  are much more resistant to hydrolysis than poly-

  These differences in behavior are considerable since in 30 minutes they are hydrolysed with a yield of 98.7%, whereas the former are only hydrolysed at 11%.

16 hours.

  It is also known that the polymerization of derivatives of acrylic acid is highly exothermic; the heat of polymerization of acrylamide is for example 19.8 0.7 Kcal / mole (FR 2246573) - It is therefore a question of being able to control the polymerization of quaternized or salified dimethylaminoethyl acrylate, in particular

  with a view to obtaining powder copolymers without

gradation of the cationic chain.

  In the prior art various solutions have been found to solve this problem. U.S. Patent 4138539 discloses a continuous polymerization process comprising a mobile polymerization zone,

  but this process requires an investment in

  which can not be made profitable by other manufacturers.

  as is the case for conventional equipment

- versatile.

  Another difficulty is to obtain poly-

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  electrolytes according to the invention, in powder form, containing as little water as possible and not requiring subsequent grinding, a very troublesome factor of dust and fines

for users.

  In the prior art, it is known to prepare acrylamide copolymers relatively easily.

  and quaternized dimethylaminoethyl acrylate or

  dissolved in water by performing the copolymerization

  at a suitable pH; but even at low concentrations, gels are obtained which are almost impossible to convert into powder. However, for industrial use it is preferable that polyelectrolytes

  in the form of an easier and less expensive powder

  to be transported as aqueous solutions.

  The polyelectrolytes according to the invention can be obtained by any suitable method. For example, according to an advantageous embodiment, the copolymerization of acrylamide and acrylate is carried out.

  quaternized or salified dimethylaminoethyl in

  necessary portions in inverted emulsion, water in oil

  (i.e., in water in the presence of a water immiscible organic solvent) and an initiator, at a pH of between 3 and 6, preferably between 4.5 and 6, then to dehydration at a lower temperature

  at 80 C, so as to avoid any phenomenon of hydrolysis.

  Dehydration can be carried out either by distillation

  azeotropic solution of the water with the solvent used during the polymerization, if the latter allows it, either by decantation, filtration, washing with a solvent miscible with water such as acetone and drying the polymer in bed

  fluidized at a temperature below 75 C.

  The organic solvent used is an aliphatic or cyclanic hydrocarbon such as heptane, branched C10 to C12 aliphatic hydrocarbon mixtures or

cyclohexane.

  Heptane and cyclohexane are preferred.

  allow the copolymer to be dehydrated azeotropically.

2471391 '

  The concentration of the monomers in the aqueous phase

  may vary from 40 to 70% and, as has been indicated-

  above, the monomer mixture can contain 50

  99% cationic monomer expressed in moles.

  As an initiator, any conventional initiation system may be used, for example photoinitiators in the presence of light, the compounds

  azoles, peroxides, organic hydroperoxides (

  benzoyl hydrate, cumene hydroperoxide) and persul-

  alkaline fats, alone or assisted, with, as

  tertiary amines (dimethylparatoluidine, triethanolamine), organic salts and

  transition metals (cobalt II octoate, acetyl-

  iron acetonate III), alkali sulphites, thiosulfates and metabisulphites, etc. The emulsifiers used are naturally

  those of low HLB (degree of hydrophilic balance, lipophilic

  Hydrophilic lipophilic balance), preferably the esters

  sorbitan fat, for example sorbitan monooleate

tanned.

  The following examples are given-for ex-

  plicative and in no way limiting to obtain the

products according to the invention.

  EXAMPLE 1 Copolymer AAM-CMA-30/70 A solution of 4 g of sorbitan monooleate in 468 g of cyclohexane is then introduced into a 2-liter reactor and, after purging the air with nitrogen, under nitrogen and with stirring a

  solution of 172.8 g (0.89 mole) of dimethylacrylate

  minoethyl quaternized with methyl chloride, CMA, and 27.2 g (0.38 mole) of acrylamide, AAM, in 200 g of water whose pH is adjusted to 4.5 by addition of acid

diluted sulfuric acid.

  It is then always introduced with stirring

  and in a nitrogen atmosphere a solution of 0.043 g of hydro-

  70% cumene peroxide in 12 g of cyclohexane and then, a few minutes later, dropwise

* 2471 391

  a solution of 0.040 g of sodium metabisulphite in g of water. As a result, the copolymerization reaction starts; the reaction temperature reaches 70-75 C

  in 5-10 minutes. After an hour of agitation in the

  In the reaction, the water is removed by azeotropic distillation to a residual water content of 15%. Then, the cooled reaction medium at room temperature is filtered, then the filtrate is washed with cyclohexane (170 ml) and finally it is dried in a fluidized bed at 95 C for 30 minutes. An AAM-CMA 30/70 copolymer, in powder form with a solids content of 96% by solids content, is thus isolated and has an intrinsic viscosity measured at C in a molar solution of sodium chloride of 8.5 dl g. and a measured cationicity of 4.2 μg / g, or 94.5% of

the theoretical cationicity.

  Examples 2 - 3 - Copolymers AAM - CMA - 20/80 and 40/60 The procedure is as in Example 1, but with 0.95 Moles of quaternized dimethylaminoethyl acrylate.

  by methyl chloride, CMA, and 0.24 mole of acrylamide

  of AAM, ie 0.83 moles of CMA and 0.55 moles of AAM.

  The AAM-CMA copolymers containing, in molar proportions, 80% CMA and 20% AAM, ie 60%, are thus obtained.

  CMA and 40% AAM. These copolymers have a cationic

  measured greater than 94% of the theoretical cationicity.

  EXAMPLE 4 Copolymer AAM-CHA 30/70 The procedure is as in Example 1, but with 0.95 mole of dimethylaminoethyl acrylate hydrochloride and 0.41 mole of acrylamide and, if necessary, by adjusting the pH of the solution. aqueous pH = 4.5 with acid

  diluted hydrochloric acid or with dilute ammonia.

  An AAM-CHA-30/70 copolymer, in powder form, is thus isolated, having an intrinsic viscosity measured at 25 ° C. in molar solution of sodium chloride of

  8.8 dl and a measured cationicity of 94.5% of the cationic

g

theoretical city.

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  Products such as those resulting from the above examples have been shown to be effective in applications

  referred to in Tables V and VI above.

  They also gave satisfactory results.

  when applied for the coalescence of emulsions such as industrial fluids based on petroleum products, emulsions from groundwater exploitation, etc. It goes without saying that the invention has been described only in a purely explanatory and non-limiting manner and that any useful modification can be made

  without departing from its scope as defined by the

hereinafter.

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Claims (6)

  1. Cationic cationic polyelectrolytes   soluble in water consisting of copolymers of acryl-   amide and quaternized or salified dimethylaminoethyl acrylate having an intrinsic viscosity greater than 6 dl measured at 25 C in molar solution of sodium chloride g and a measured cationicity greater than 90% of the theoretical cationicity, characterized by the fact that contain, in molar proportions, more than 50% of cationic units distributed regularly along copolymer chains.   Cationic polyelectrolytes according to claim 1, characterized in that the acrylate   of dimethylaminoethyl is salified by chlorhydroxy drique.   3. Cationic polyelectrolytes according to claim 1 characterized in that dimethylaminoethyl acrylate is quaternized by chloride of methyl.   4. Application of cationic polyelectrolytes   powder compositions according to any of the claims   1 to 3, characterized in that said polyelectrolytes are   These are used for the floeulation of colloidal suspensions of solids and / or coalescence emulsions.   5. Application of cationic polyelectrolytes   according to claim 4, characterized by the fact   said polyelectrolytes are used for the treatment of   urban and / or industrial sludge.   6. Application of the cationic polyelectrolytes according to claim 7, characterized in that said polyelectrolytes are used at a dose of 1   at 5 kg per tonne of dry matter of the media to be treated.