U.S. patent application number 09/757997 was filed with the patent office on 2001-12-13 for process for the preparation of free-flowing strongly acidic cation exchangers.
Invention is credited to Bachmann, Reinhard, Feistel, Lothar, Seidel, Rudiger, Siekiera, Karl-Heinz, Wegewitz, Kurt.
Application Number | 20010051664 09/757997 |
Document ID | / |
Family ID | 27215765 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010051664 |
Kind Code |
A1 |
Bachmann, Reinhard ; et
al. |
December 13, 2001 |
Process for the preparation of free-flowing strongly acidic cation
exchangers
Abstract
The invention relates to processes for the preparation of
free-flowing end products of strongly acidic cation exchangers. In
the case of the strongly acidic cation exchangers prepared by the
processes described in Patent Application P 195 48 012.0, the
particle beds of the end products are not free-flowing. By
additions of wetting agents or water-soluble initiators or
surfactants in the polymerization stage or after the filtration of
the end product and/or process engineering means, a permanent or
temporary free flowability of the particle beds of the strongly
acidic cation exchangers is achieved using the following processes.
1. By additions of known wetting agents in amounts of 0.25 g/l of
aqueous phase or water-soluble initiators in amounts of 0.05 to 20
g/l of aqueous phase to the copolymerization system 20 minutes to
120 minutes after reaching the gel point. 2. By treatment of the
strongly acidic cation exchangers with aqueous solutions of
surface-active substances having a content of 0.1 to 5 g/l in the
batch or column process. 3. By washing the strongly acidic cation
exchangers for 1 to 4 hours with hot water at at least 60.degree.
C., subsequently separating off the water and drying the end
product with utilization of the intrinsic heat.
Inventors: |
Bachmann, Reinhard;
(Engelsdorf, DE) ; Feistel, Lothar; (Delitzsch,
DE) ; Seidel, Rudiger; (Sandersdorf, DE) ;
Siekiera, Karl-Heinz; (Wolfen, DE) ; Wegewitz,
Kurt; (Bitterfeld, DE) |
Correspondence
Address: |
William C. Gerstenzang
Norris McLaughlin & Marcus, P.A.
220 East 42nd Street - 30th Floor
New York
NY
10017
US
|
Family ID: |
27215765 |
Appl. No.: |
09/757997 |
Filed: |
January 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09757997 |
Jan 10, 2001 |
|
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09091559 |
Jun 18, 1998 |
|
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|
09091559 |
Jun 18, 1998 |
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PCT/EP96/05785 |
Dec 20, 1996 |
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Current U.S.
Class: |
521/26 ;
521/28 |
Current CPC
Class: |
C08F 8/36 20130101; C08F
212/08 20130101; C08F 8/36 20130101; B01J 39/20 20130101; C08F
2800/20 20130101 |
Class at
Publication: |
521/26 ;
521/28 |
International
Class: |
C08J 005/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 1995 |
DE |
195 48 011.2 |
Oct 24, 1996 |
DE |
196 44 222.2 |
Claims
1. Process for the preparation of free-flowing strongly acidic
cation exchangers which are obtained by sulphonation of
styrene/divinylbenzene copolymers by means of sulphuric acid,
characterized in that free-flowing strongly acidic cation
exchangers can be prepared by one of the three stated processes: 1.
By additions of known wetting agents in amounts of 0.25 g/l of
aqueous phase or water-soluble initiators in amounts of 0.05 to 20
g/l of aqueous phase to the copolymerization system 20 minutes to
120 minutes after reaching the gel point, 2. By treatment of the
strongly acidic cation exchangers after the filtration with aqueous
solutions of surface-active substances having a content of 0.1 to 5
g/l in the batch or column process, 3. By washing the strongly
acidic cation exchangers for 1 to 4 hours after the filtration with
hot water at at least 60.degree. C., subsequently separating off
the water and drying the end product with utilization of the
intrinsic heat.
2. Process for the preparation of free-flowing strongly acidic
cation exchangers according to claim 1, point 1, characterized in
that sodium salts of alkanesulphonic acids having a chain length of
C.sub.12-C.sub.18, as wetting agents, or potassium peroxydisulphate
(K.sub.2S.sub.2O.sub.8), as water-soluble initiator, are added to
the copolymerization system.
3. Process for the preparation of free-flowing strongly acidic
cation exchangers according to claim 1, point 2, characterized in
that the aqueous solutions contain a surface-active substance or a
mixture of surface-active substances.
4. Process for the preparation of free-flowing strongly acidic
cation exchangers according to claim 1, point 2, and claim 3,
characterized in that adducts of ethylene oxide and propylene oxide
with natural fatty alcohols having a chain length C.sub.12-C.sub.14
or alkylphenol polyethylene glycol ethers, as nonionic surfactants,
fatty alcohol polyalkylene glycol ethers, as cationic and
amphoteric surfactants or emulsifiers, paraffinsulphonates, as
anionic surfactants, are used as surface-active substances.
5. Process for the preparation of free-flowing strongly acidic
cation exchangers according to claim 1, point 2, and claim 3,
characterized in that sorbitan fatty acid esters and/or
polyoxyethylene (20) sorbitan fatty acid esters are used as
surface-active substances for cation exchangers used in the food
industry.
Description
[0001] The invention relates to processes for the preparation of
free-flowing end products of strongly acidic cation exchangers
prepared according to Patent Application P 195 48 012.0.
[0002] Strongly acidic cation exchangers prepared by the processes
of the publications cited in Patent Application P 195 48 012.0 with
and without the use of inert swelling agents, as well as the
strongly acidic cation exchangers prepared by the process according
to the invention and of the patent application mentioned, have the
disadvantageous property that the cation exchanger dewatered in a
filter at the end of the preparation process are not sufficiently
free-flowing for industrial handling, further processing and
use.
[0003] EP 0 009 395 discloses the addition of wetting agents and
water-soluble initiators in the polymerization stage. With the aid
of the additions, the formation of an emulsion of extremely
fine-particled ion exchangers, particle size 0.01-1.5 .mu.m, is
achieved but the surface charge of coarse particles in the
anhydrous state is not influenced in such a way that they become
free-flowing as bulk material. The treatment of sulphonated
styrene/divinylbenzene copolymer with water is part of the
preparation process described in EP 0 009 395 for cation
exchangers. The end products thus prepared are not
free-flowing.
[0004] EP 0 223 596 A 2 describes the hydration of the sulphonated
product containing sulphuric acid in the process for the
preparation of a cation exchanger.
[0005] However, the treatment of the sulphonated cation exchanger
with water in this process stage does not result in the free
flowability of the end product. The relevant technical literature
proposes no solutions for eliminating these disadvantageous
properties of the particle beds of strongly acidic cation
exchangers.
[0006] It is the object of the invention to influence the
preparation process of strongly acidic cation exchangers by
suitable additions of substances and/or process engineering
measures so that the particle beds of the end products are
free-flowing.
[0007] It has now been found that free-flowing strongly acidic
cation exchangers can be prepared by means of additions of
substances and process engineering measures in the polymerization
stage or after the filtration of the end product. Specifically,
these are subsequent procedures according to the invention which
lead to a substance known per se and having novel properties:
[0008] 1. Free-flowing end products are obtained if the preparation
of the starting material for the strongly acidic cation exchanger,
the styrene/divinylbenzene copolymer is influenced in such a way
that a higher proportion of emulsion polymer forms. This is
achieved, according to the invention, by adding
[0009] wetting agents, e.g. sodium salts of alkanesulphonic acids
having a chain length C.sub.12-C.sub.18 in a concentration of up to
0.25 g/l of water or
[0010] 0.05 to 0.20 g/l of water of a water-soluble initiator, such
as, for example, potassium peroxydisulphate
(K.sub.2S.sub.2O.sub.8)
[0011] to the batch of the copolymerization system 20 to 120 min
after reaching the gel point.
[0012] Strongly acidic cation exchangers prepared according to
Examples 1 and 2 are permanently free-flowing.
[0013] 2. Free-flowing end products are also obtained if the
non-free-flowing strongly acidic cation exchangers prepared by the
procedure cited are treated with surface-active substances, such as
nonionic surfactants, as prepared by an addition reaction of
ethylene oxide and propylene oxide with natural fatty alcohols
having a chain length C.sub.12-C.sub.14, or
[0014] alkylphenol polyethylene glycol ethers or cationic and
amphoteric surfactants or emulsifiers of the fatty alcohol
polyalkylene glycol ether type or anionic surfactants of the
paraffinsulphonate type.
[0015] If the strongly acidic cation exchanger is used in the food
industry (e.g. drinking water preparation), the surface-active
substance must be suitable as an additive for food. Sorbitan fatty
acid esters and polyoxyethylene(20) sorbitan fatty acid esters may
be used for this purpose.
[0016] According to the invention, this is achieved by treating the
end products dewatered in a filter at the end of the preparation
process, in a downstream batch or column process, with an aqueous
solution which contains a surface-active substance or a mixture of
surface-active substances in amounts of 0.1 to 5 g/l of resin. The
products are then dewatered and dispatched. The free flowability
produced here is temporary and eliminated again by washing with
water. Such free-flowing strongly acidic cation exchangers can be
prepared according to Examples 3 and 4.
[0017] 3. Free-flowing strongly acidic cation exchangers are
furthermore obtained by subjecting the end products, the
non-free-flowing strongly acidic cation exchangers, to a hot water
wash which simultaneously purifies the end products and utilizes
the heat content of the end products for its superficial drying.
According to the invention, the desired effect is achieved by
treating the non-free-flowing strongly acidic cation exchangers
with hot water at a temperature equal to or higher than 60.degree.
C. for at least 1 hour, not more than 4 hours, and drying the said
cation exchangers after removal of the water utilizing the product
heat. By passing through air- or nitrogen, the removal of moisture
is accelerated, the residual moisture content is reduced and the
free-flowing state of the strongly acidic cation exchanger is
reached earlier.
[0018] Strongly acidic cation exchangers prepared according to
Examples 5 to 7 are temporarily free-flowing.
[0019] To evaluate the free flowability, the efflux characteristic
from a defined funnel was determined. The dimensions of the funnel
are shown in the attached drawing sheet.
[0020] The material of the funnel, each having the same internal
dimensions, consisted
[0021] a) of Teflon and
[0022] b) of C2A stainless steel.
[0023] The sample material is filled loosely into the funnel.
[0024] The outlet orifice of the funnel is closed.
[0025] To carry out the flow test, the funnel outlet is opened
without vibration.
[0026] The flowability of the strongly acidic cation exchangers is
assessed according to the following criteria:
[0027] 1. Total material flows by itself out of the funnel
[0028] 2. Only the lower part of the funnel flows out
spontaneously, and the complete content as a result of lightly
tapping the funnel
[0029] 3. The lower part of the funnel flows out spontaneously; the
sample material remains in the upper part of the funnel even with
intensive tapping
[0030] 4. The lower part of the funnel flows out of the funnel only
after intensive tapping
[0031] 5. No material at all flows out of the funnel, not even with
tapping.
[0032] End products having the rating 1 are classified as
"free-flowing". Since the funnel material considerably influences
the efflux behaviour of the end products, the abovementioned
evaluations must be carried out in both funnels.
[0033] Using the processes according to the invention, the
disadvantages associated with the end products are overcome and the
following advantageous properties and effects achieved.
[0034] The products are free-flowing
[0035] The free flowability does not give rise to any technical
problem in packaging in the production unit.
[0036] No metering problems into small containers at the customer's
premises
[0037] An additional purification of the product occurs during the
hot washing/separation/drying variant
[0038] The additions of substances to the copolymerization system
have the advantage that an after-treatment of the end products
after the filtration is dispensed with.
EXAMPLE 1
[0039] Polymerization is carried out as follows in a polymerization
apparatus consisting of a 2 l beaker having a plane ground joint
and equipped with stirrer, contact thermometer, gas inlet tube and
condenser and infrared heating:
[0040] 900 ml of spring water are initially introduced and 7.3 g of
anhydrous MgSO.sub.4 and 20 g of NaCl are dissolved. Thereafter, 25
ml of Wotamol solution (1 g/l) and 11 ml of Sapal solution (1 g/l)
are added and heating is carried out at 40.degree. C. and 5.8 g of
caustic soda, dissolved in 100 ml of water, are added and heating
is carried out to 71.degree. C.
[0041] At this temperature, 500 g of the polymerizable phase are
added while blanketing with nitrogen (5-10 l/h). The said phase
consists of 442.5 g of styrene, 57.7 g of divinylbenzene (65.14%
strength) and 0.45 g of Perkadox as initiator. The organic phase is
distributed over the desired particle size by stirring and is kept
at this temperature. The organic substances polymerize and go into
the gel-like state. Once this has occurred, the temperature is kept
at 69.degree. C. for 3 h. 1 h after the gel point 250 mg of the
wetting agent Mersolat (tradename for Na salts of alkanesulphonic
acids of the chain length C.sub.12-C.sub.18) are introduced into
the suspension.
[0042] After the polymerization phase, heating is carried out to
95.degree. C. and curing is effected at this temperature for 4 h.
The total batch is cooled to room temperature, then added to a 0.25
mm sieve and separated from the aqueous phase and the polymer is
washed neutral with spring water and filtered off with suction. The
polymer is dried for 2 h at 105.degree. C. and sieved. 50 g of the
particle fraction 0.25-0.8 mm are swollen in the customary manner
with dichloroethane and sulphonated with 200 ml of conc. sulphuric
acid for 6 h at 105.degree. C. After cooling to room temperature,
the product is separated from the sulphuric acid and is thoroughly
washed stepwise with 60, 40, 20% strength sulphuric acid, 20%
strength, 10% strength NaCl solution and water and rendered neutral
with dilute sodium hydroxide solution. The strongly acidic cation
exchanger obtained is free-flowing.
EXAMPLE 2
[0043] In the same polymerization apparatus as described in Example
1, an analogous aqueous phase is prepared and heated to 71.degree.
C. The organic phase consisting of the same component in the same
mixing ratios is added and polymerized. 2 hours after the gel
point, 200 mg of potassium peroxydisulphate are added and the
polymerization is completed as in Example 1. The polymer is then
separated off, worked up and sulphonated under the same conditions,
also as in Example 1. The product is free-flowing.
EXAMPLE 3
[0044] 250 ml of a strongly acidic cation exchanger based on a
styrene/divinylbenzene copolymer having a divinylbenzene content of
7.8% by weight in the sodium form are placed on a frit and treated
for up to 60 min with 500 ml of a 0.1% strength solution of the
emulsifier Lamesorb SML-20 and then filtered off with suction. The
product is free-flowing.
EXAMPLE 4
[0045] 250 ml of a strongly acidic exchanger analogous to Example 3
are placed on a filter and treated for up to 20 min with 500 ml of
a 0.4% strength antifoam solution 7800 and then filtered off with
suction. The product is free-flowing.
EXAMPLE 5
[0046] 5 m.sup.3 of a cation exchanger analogous to Example 3 are
stirred with 4-5 m.sup.3 of water for 2 h at 65.degree. C. in a
wash vessel, discharged into a filter, dewatered and transferred to
a cyclone and treated with 500 m.sup.3 of air per m.sup.3 of
exchanger over a period of 2 h. The product is free-flowing and has
42% of moisture.
[0047] The separation of the product from the wash water can also
be effected by means of a screen centrifuge.
EXAMPLE 6
[0048] 200 ml of a strongly acidic cation exchanger as in Example 3
are made into a slurry with 200 ml of water and stirred for 2 h at
80.degree. C. Thereafter, the slurry is transferred to a filter and
separated from the liquid, and air is sucked through in an amount
of 30 l/h. During this procedure, the material cools down (to
20.degree. C.) and is free-flowing after 20 minutes.
EXAMPLE 7
[0049] 23 kg of a strongly acidic cation exchanger--as in Example
3--are made into a slurry with 46 l of warm water at 63.degree. C.
and stirred for 30 minutes. The slurry was then separated on a
Konturbex H 250 screen centrifuge from the company Siebtechnik
Mulheim/Ruhr. The resin having a layer height of 5-15 mm was
brought into contact with the room air without movement and was
free-flowing after 23 minutes.
* * * * *