U.S. patent application number 14/324329 was filed with the patent office on 2014-12-25 for method for preparing olefin fluorine compounds.
The applicant listed for this patent is Jean-Michel Bossoutrot, Pierre-Marie Sedat. Invention is credited to Jean-Michel Bossoutrot, Pierre-Marie Sedat.
Application Number | 20140378717 14/324329 |
Document ID | / |
Family ID | 41665381 |
Filed Date | 2014-12-25 |
United States Patent
Application |
20140378717 |
Kind Code |
A1 |
Bossoutrot; Jean-Michel ; et
al. |
December 25, 2014 |
Method for Preparing Olefin Fluorine Compounds
Abstract
The invention relates to a method for preparing olefin fluorine
compounds. Specifically, the invention relates to a method for
producing a (hydro)fluoroolefin compound, including: (i) in an
agitated reactor provided with at least one reactant inlet and at
least one outlet, contacting, with potassium hydroxide in an
aqueous reaction medium, at least one compound containing three to
six carbon atoms, at least two fluorine atoms, and at least one
hydrogen atom, with the proviso that at least one hydrogen atom and
one fluorine atom are located on adjacent carbon atoms, so as
produce the (hydro)fluoroolefin compound, separated in a gaseous
state from the reaction medium and from potassium fluoride; (ii) in
an aqueous medium, contacting the potassium fluoride formed in step
(i) with calcium hydroxide in a second reactor so as to produce
potassium. hydroxide and to precipitate calcium tluoride; (iii)
separating the calcium fluoride precipitated in step (ii) from the
reaction medium; and (iv) optionally recirculating the reaction
medium after optionally recirculating the reaction medium after
optionally adjusting the concentration of potassium hydroxide in
step (i), characterized in that potassium hydroxide, with regard to
the reaction medium of step (ii), is between 10 and 35 wt % of the
weight of the water/potassium hydroxide mixture of the medium.
Inventors: |
Bossoutrot; Jean-Michel;
(Chaponost, FR) ; Sedat; Pierre-Marie; (Fleurieux
Sur L'Arbresle, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bossoutrot; Jean-Michel
Sedat; Pierre-Marie |
Chaponost
Fleurieux Sur L'Arbresle |
|
FR
FR |
|
|
Family ID: |
41665381 |
Appl. No.: |
14/324329 |
Filed: |
July 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13384256 |
Jan 19, 2012 |
8809601 |
|
|
PCT/FR2010/050970 |
May 19, 2010 |
|
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|
14324329 |
|
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Current U.S.
Class: |
570/155 |
Current CPC
Class: |
C01F 11/22 20130101;
C01P 2004/61 20130101; C07C 17/25 20130101; C01P 2006/80 20130101;
C07C 17/25 20130101; C07C 21/18 20130101 |
Class at
Publication: |
570/155 |
International
Class: |
C07C 17/25 20060101
C07C017/25 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 23, 2009 |
FR |
0955137 |
Claims
1. Process for the continuous or semicontinuous manufacture of a
(hydro)fluoroolefin compound comprising (i) bringing at least one
compound comprising from three to six carbon atoms, at least two
fluorine atoms and at least one hydrogen atom, provided that at
least one hydrogen atom and one fluorine atom are situated on
adjacent carbon atoms, into contact with potassium hydroxide in an
aqueous reaction medium in a stirred reactor equipped with at least
one inlet and with at least one outlet, to give the
(hydro)fluoroolefin compound, which is separated from the reaction
medium in the gaseous form, and potassium fluoride, (ii) bringing
the potassium fluoride formed in (i) into contact in an aqueous
medium with calcium hydroxide in a second reactor, to give
potassium hydroxide and calcium fluoride precipitate, (iii)
separating the calcium fluoride precipitated in stage (ii) from the
reaction medium and (iv) optionally recycling the reaction medium
to stage (i) after optional adjustment of the concentration of
potassium hydroxide, characterized in that the potassium hydroxide
represents, in the reaction medium of stage (ii), between 10 and
35% by weight, with respect to the weight of the water and
potassium hydroxide mixture of the medium.
2. Process according to claim 1, characterized in that the
(hydro)fluoroolefin comprises a compound of formula (1)
CF.sub.3CY=CX.sub.nH.sub.p (I) in which Y represents a hydrogen
atom or a halogen atom chosen from fluorine, chlorine, bromine or
iodine, X represents a halogen atom chosen from fluorine, chlorine,
bromine or iodine, and n and p are integers and can independently
take the value zero, 1 or 2, provided that (n+p)=2, and said at
least one compound comprises a compound of formula
CF.sub.3CYRCR'X.sub.nH.sub.p, where R represents a fluorine atom
when R' represents a hydrogen atom or R represents a hydrogen atom
when R' represents a fluorine atom.
3. Process according to claim 1, characterized in that the
(hydro)fluoroolefin comprises a compound of formula (Ia)
CF.sub.3CF=CHZ (Ia) in which Z represents a hydrogen atom or a
fluorine atom, and said at least one compound comprises a compound
of formula CF.sub.3CFRCHR'Z, where R represents a fluorine atom
when R' represents a hydrogen atom or R represents a hydrogen atom
when R' represents a fluorine atom.
4. Process according to claim 1, characterized in that said
(hydro)fluoroolefin comprises 2,3,3,3-tetrafluoropropene and said
at least one compound comprises 1,1,1,2,3-pentafluoropropane into
contact with potassium hydroxide and/or
1,2,3,3,3-pentafluoropropene.
5. Process according to claim 1, characterized in that the
potassium hydroxide represent between 20 and 75% by weight, with
respect to the weight of the water and KOH mixture present in the
aqueous reaction medium of stage (i).
6. Process according to claim 1, characterized in that the
temperature at which stage (i) is carried out is between 80 and
180.degree. C.
7. Process according to claim 1, characterized in that the
temperature of stage (ii) is between 50 and 150.degree. C.
8. Process according to claim 1, characterized in that stage (ii)
is fed with potassium fluoride via the reaction medium originating
from stage (i).
9. Process according to claim 1, characterized in that the
potassium fluoride represents between 4 and 45% by weight of the
reaction medium from stage (i).
10. Process according to claim 8, further characterized in that
water is added to the reaction medium of stage (ii).
11. Process according to claim 1, characterized in that the calcium
fluoride in stage (iii) is filtered off after an optional settling
stage.
12. Process according to claim 11, characterized in that, during
settling, a portion of the concentrated calcium fluoride suspension
is recycled to stage (ii).
13. Process according to claim 1, characterized in that said
(hydro)fluoroolefin comprises 1,2,3,3,3-pentafluoropropene and said
at least one compound comprises 1,1,1,2,3,3-hexafluoropropane.
14. Process according claim 1, characterized in that the potassium
hydroxide represent between 55 and 70% by weight, with respect to
the weight of the water and KOH mixture.
15. Process according to claim 1, characterized in that the
temperature at which stage (i) is carried out is between 125 and
180.degree. C.
16. Process according to claim 1, characterized in that the
temperature at which stage (i) is carried out is between 145 and
165.degree. C.
17. Process according to claim 1, characterized in that the
temperature of stage (ii) is Between 70 and 120.degree. C.
18. Process according to claim 1, characterized in that the
temperature of stage (ii) is between 70 and 100.degree. C.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/384,256, filed Jan. 19, 2012, which is a
National Stage application of International Application No.
PCT/FR2010/050970, filed May 19, 2010. This application also claims
priority under 35 U.S.C. .sctn.119 to French Patent Application No.
0955137, filed Jul. 23, 2009.
FIELD OF THE INVENTION
[0002] A subject-matter of the invention is a process for the
preparation of fluoroolefin compounds. The invention relates more
particularly to a process for the preparation of
hydrofluoropropenes.
TECHNOLOGICAL BACKGROUND
[0003] Hydrofluorocarbons (HFCs) and in particular
hydrofluoroolefins (HFOs), such as 2,3,3,3-tetrafluoro-1-propene
(HFO-1234yf), are compounds known for their properties of
refrigerants and heat-exchange fluids, extinguishers, propellants,
foaming agents, blowing agents, gaseous dielectrics, monomer or
polymerization medium, support fluids, agents for abrasives, drying
agents and fluids for energy production units. Unlike CFCs and
HCFCs, which are potentially dangerous to the ozone layer, HFOs do
not comprise chlorine and thus do not present a problem for the
ozone layer.
[0004] 1,2,3,3,3-Pentafluoropropene (HFO-1225ye) is a synthetic
intermediate in the manufacture of 2,3,3,3-tetrafluoro-1-propene
(HFO-1234yf).
[0005] The majority of the processes for the manufacture of
hydrofluoroolefins involve a dehydrohalogenation reaction. Thus,
the document WO 03/027051 describes a process for the manufacture
of fluoroolefins of formula CF.sub.3CY=CX.sub.nH.sub.p, in which X
and Y each represent a hydrogen atom or a halogen atom chosen from
fluorine, chlorine, bromine or iodine and n and p are integers and
can independently take the value zero, 1 or 2, provided that
(n+p)=2, which comprises bringing a compound of formula,
CF.sub.3C(R.sup.1.sub.aR.sup.2.sub.b)C(R.sup.3.sub.cR.sup.4.sub.d)
with R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently
representing a hydrogen atom or a halogen atom chosen from
fluorine, chlorine, bromine or iodine, provided that at least one
of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is a halogen atom and that
at least one hydrogen atom and one halogen atom are situated on
adjacent carbon atoms, a and b being able independently to take the
value zero, 1 or 2, provided that (a+b)=2, and c and d being able
independently to take the value zero, 1, 2 or 3, provided that
(c+d)=3, into contact with at least one alkali metal hydroxide in
the presence of a phase transfer catalyst.
[0006] This document teaches, in Example 2, that, in the absence of
a phase transfer catalyst, there is no reaction when
1,1,1,3,3-pentafluoropropane (HFC-245fa) is brought into contact
with a 50% by weight aqueous potassium hydroxide (KOH) solution at
ambient temperature and under pressure for 24 hours.
[0007] In addition, this document teaches a reaction temperature of
between -20.degree. C. and 80.degree. C.
[0008] The document WO 2008/075017 illustrates the
dehydrofluorination reaction of 1,1,1,2,3,3-hexafluoropropane
(HFC-236ea) to give 1,2,3,3,3-pentafluoropropene (HFO-1225ye) at
150.degree. C. in the presence of a 50% by weight aqueous KOH
solution. In the absence of a phase transfer catalyst, the
conversion after 3 and a half hours is 57.8% and the selectivity
for HFO-1225ye is 52.4% (Test 1). In the presence of a phase
transfer catalyst, this conversion is achieved after only 2.5 hours
and the selectivity is virtually unchanged (Test 4). As indicated
in Table 2 of this document, it is necessary to use an organic
solvent in order to increase the selectivity for HFO-1225ye.
[0009] WO 2007/056194 describes the preparation of HFO-1234yf by
dehydrofluorination of 1,1,1,2,3-pentafluoropropane (HFC-245eb)
either with an aqueous KOH solution or in the gas phase in the
presence of a catalyst, in particular over a catalyst based on
nickel, carbon or a combination of these.
[0010] The document Knunyants et al., Journal of the USSR Academy
of Sciences, Chemistry Department, "Reactions of fluoro-olefins",
Report 13, "Catalytic hydrogenation of perfluoro-olefins", 1960,
clearly describes various chemical reactions on fluorinated
compounds. This document describes the dehydrofluorination of
1,1,1,2,3,3-hexafluoropropane (236ea) by passing through a
suspension of KOH powder in dibutyl ether, to produce
1,2,3,3,3-pentafluoro-1-propene (HFO-1225ye) with a yield of only
60%. This document also describes the dehydrofluorination of
1,1,1,2,3-pentafluoropropane (HFC-245eb) to give
2,3,3,3-tetrafluoro-1-propene (HFO-1234yf) by passing into a
suspension of KOH powder in dibutyl ether with a yield of only
70%.
[0011] Furthermore, FIG. 2 on page 51 of Part 2 of the nouveau
traite de chimie minerale [New Treatise on Inorganic Chemistry] by
P. Pascal, Ed. 1963, shows the appearance of the liquid/solid
equilibria of the water and potassium hydroxide system and the
measurements are collated in the table on page 52.
[0012] The dehydrofluorination reactions as described above result,
in addition to the desired hydrofluoroolefin compound, in the
formation of water and potassium fluoride. Furthermore, the
implementation of such a reaction continuously is not easy on the
industrial scale as at least three phases (gas, liquid and solid)
are involved.
[0013] The present invention provides a process for the continuous
or semicontinuous manufacture of a (hydro)fluoroolefin compound
which makes it possible to overcome the abovementioned
disadvantages. A subject-matter of the present invention is thus a
process for the continuous or semicontinuous manufacture of a
(hydro)fluoroolefin compound comprising (i) bringing at least one
compound comprising from three to six carbon atoms, at least two
fluorine atoms and at least one hydrogen atom, provided that at
least one hydrogen atom and one fluorine atom are situated on
adjacent carbon atoms, into contact with potassium hydroxide in an
aqueous reaction medium in a stirred reactor equipped with at least
one inlet for the reactants and with at least one outlet, to give
the (hydro)fluoroolefin compound, which is separated from the
reaction medium in the gaseous form, and potassium fluoride, (ii)
bringing the potassium fluoride formed in (i) into contact in an
aqueous medium with calcium hydroxide in a second reactor, to give
potassium hydroxide and to precipitate calcium fluoride, (iii)
separating the calcium fluoride precipitated in stage (ii) from the
reaction medium and (iv) optionally recycling the reaction medium
to stage (i) after optional adjustment of the concentration of
potassium hydroxide, characterized in that the potassium hydroxide
represents, in the reaction medium of stage (ii), between 10 and
35% by weight, with respect to the weight of the water and
potassium hydroxide mixture of the medium.
[0014] The present invention thus makes it possible to obtain an
advantageous process as, on the one hand, potassium hydroxide is
more reactive than calcium hydroxide in the dehydrofluorination
reaction and, on the other hand, the conversion of the calcium
hydroxide to give calcium fluoride, a by-product which can be
recovered in value, is high.
[0015] The Applicant Company has observed that the process
according to the present invention makes it possible to obtain a
mean size at 50% by weight of the particle size distribution of
calcium fluoride crystals of greater than 10 .mu.m, indeed even of
greater than 20 .mu.m and more particularly of between 20 and 60
.mu.m and thus to facilitate the washing and filtration operations
and the recycling of the potassium hydroxide.
[0016] The reaction medium of stage (i) is stirred so as to provide
for dispersion of the gas in the liquid medium.
[0017] The process according to the present invention preferably
provides a (hydro)fluoroolefin compound comprising three carbon
atoms, advantageously a (hydro)fluoroolefin compound represented by
the formula (I)
CF.sub.3CY=CX.sub.nH.sub.p (I)
in which Y represents a hydrogen atom or a halogen atom chosen from
fluorine, chlorine, bromine or iodine, X represents a halogen atom
chosen from fluorine, chlorine, bromine or iodine, and n and p are
integers and can independently take the value zero, 1 or 2,
provided that (n+p)=2, by bringing a compound of formula
CF.sub.3CYRCR'X.sub.nH.sub.p, in which X, Y, n and p have the same
meanings as in the formula (I) and R represents a fluorine atom
when R' represents a hydrogen atom or R represents a hydrogen atom
when R' represents a fluorine atom, into contact with potassium
hydroxide in stage (i).
[0018] The present invention is very particularly suited to the
manufacture of a compound of formula (Ia)
CF.sub.3--CF=CHZ (Ia)
in which Z represents a hydrogen atom or a fluorine atom, starting
from a compound of formula CF.sub.3CFRCHR'Z in which Z has the same
meanings as in the formula (Ia) and R represents a fluorine atom
when R' represents a hydrogen atom or R represents a hydrogen atom
when R' represents a fluorine atom.
[0019] Thus, 2,3,3,3-tetrafluoropropene can be obtained by
dehydrofluorination of 1,1,1,2,3-pentafluoropropane with KOH and/or
1,2,3,3,3-pentafluoropropene can be obtained by dehydrofluorination
of 1,1,1,2,3,3-hexafluoropropane with KOH in stage (i). The
1,2,3,3,3-pentafluoropropene can be in the form of the cis and/or
trans isomer.
[0020] The present invention can additionally be used for the
manufacture of 1,3,3,3-tetrafluoropropene by dehydrofluorination of
1,1,3,3,3-pentafluoropropane with KOH.
[0021] In stage (i) of the process according to the present
invention, the potassium hydroxide can represent between 20 and 75%
by weight, with respect to the weight of the water and KOH mixture
present in the aqueous reaction medium, preferably between 55 and
70%. According to the content, the potassium hydroxide can be in
the form of an aqueous solution or in the molten state.
[0022] Stage (i) is generally carried out at a temperature such
that the water formed during the dehydrofluorination reaction is
removed, in all or in part, from the reaction medium by entrainment
of the gas stream comprising the (hydro)fluoroolefin compound
resulting from the stirred reactor. This temperature is preferably
between 80 and 180.degree. C., advantageously between 125 and
180.degree. C. and very particularly between 145 and 165.degree.
C.
[0023] The dehydrofluorination reaction of stage (i) can be carried
out at atmospheric pressure but it is preferable to operate at a
pressure greater than atmospheric pressure. Advantageously, this
pressure is between 1.1 and 2.5 bar.
[0024] The reaction of stage (ii) can be carried out in a stirred
reactor or a fluidized bed reactor by reacting calcium hydroxide,
preferably in suspension in water, with the potassium fluoride
originating from stage (i). The reaction temperature can vary
within wide limits but, for economic reasons, it is preferably
between 50 and 150.degree. C., advantageously between 70 and
120.degree. C. and more advantageously between 70 and 100.degree.
C.
[0025] When a calcium hydroxide suspension is used in stage (ii),
the calcium hydroxide represents between 2 and 40% by weight, with
respect to the weight of the suspension.
[0026] Advantageously, stage (ii) is fed with potassium fluoride
via the reaction medium originating from stage (i) comprising
water, potassium hydroxide and potassium fluoride. The potassium
fluoride in stage (i) can be dissolved or in suspension. The
potassium fluoride preferably represents between 4 and 45% by
weight of the reaction medium from stage (i).
[0027] In the stage (ii), two mol of potassium fluoride react with
one mol of calcium hydroxide to give one mol of potassium fluoride
and two mol of potassium hydroxide. This generation of potassium
hydroxide makes it possible to limit the optional need to
reconcentrate and thus reduces the addition of potassium hydroxide
in the process.
[0028] It is possible to provide a stage of dilution of the
reaction medium between stage (i) and stage (ii).
[0029] The calcium fluoride precipitated in stage (ii) is separated
from the reaction medium, for example by filtration and/or
settling. A settling stage can be provided prior to the filtration.
The calcium fluoride thus separated is subsequently washed with
water.
[0030] During the settling stage, it is possible to provide for the
recycling of a portion of the concentrated calcium fluoride
suspension to stage (ii). Advantageously, the level of calcium
fluoride solids present in the reaction medium of stage (ii) is
between 2 and 30% by weight.
[0031] After separation of the calcium fluoride, the reaction
medium, with or without aqueous liquors from washing the calcium
fluoride, can be recycled to stage (i), after optional adjustment
of the potassium hydroxide content.
[0032] It can be advantageous to use an inert gas in the
dehydrofluorination stage.
[0033] The process according to the invention has the advantage of
resulting in high yields, even in the absence of phase transfer
catalyst and/or organic solvent.
[0034] The present invention also comprises the combinations of the
preferred forms, whatever the embodiment.
EXPERIMENTAL PART
Example 1
[0035] 1 kg of 50% by weight potassium hydroxide comprising 9% by
weight of KF is introduced into a reactor and heated to 100.degree.
C. 109 g of Ca(OH).sub.2 assaying 96% by weight (major impurity
being CaCO.sub.3) are subsequently added with stirring at 500
revolutions/min. After reacting for one hour, the suspension is
withdrawn. The level of solids is 3.5% by weight and the
composition by weight of the solids is as follows: [0036]
CaF.sub.2: 60% [0037] Ca(OH).sub.2: 36% [0038] CaCO.sub.3: 4%
Example 2
[0039] The operation is carried out as in Example 1, except that 1
kg of 25% by weight potassium hydroxide is introduced.
[0040] The composition by weight of the solids, after reacting for
one hour, is as follows: [0041] CaF.sub.2: 95% [0042] Ca(OH).sub.2:
1% [0043] CaCO.sub.3: 4%.
Example 3
[0044] A reactor maintained at 100.degree. C. and stirred at 500
rev/min is fed continuously with a potassium hydroxide solution
resulting from the dehydrofluorination stage and assaying, after
dilution, 28% by weight of potassium hydroxide and 6% by weight of
KF. The Ca(OH).sub.2 suspension feeding the reactor assays 20% by
weight. The residence time in the reactor is approximately 1 h.
[0045] The ability to be filtered of the suspension obtained after
reaction is very good.
[0046] The level of solids of the suspension at the outlet of the
reactor is 3.6% by weight.
[0047] The particle size of the calcium fluoride synthesized is 30
.mu.m and its purity is greater than 85% by weight.
Example 4
[0048] FIG. 1 gives the diagram of an embodiment of the present
invention. A stirred reactor (1), equipped with a heating/cooling
device and a device for measuring the temperature of the reaction
medium, which comprises a water and KOH mixture in which the KOH is
present at 60% by weight in the water, is fed continuously with a
solution of molten KOH (2), in which the KOH is present at 65% by
weight in the water, and with 1,1,1,2,3,3-hexafluoropropane (3).
The temperature is maintained at 150.degree. C. and the pressure in
the reactor is 1.2 bar absolute. The gaseous products exit from the
reactor via an orifice (4) situated on the lid and the water
present in the gas stream is removed by condensation (13).
[0049] The material exiting (5) from the reactor (1) is diluted in
line with water (6) in order to obtain a KOH assay of 30%. This
mixture is conveyed to the inlet of the reactor (7) and thus
provides for the feeding of the reactor (7) with potassium
fluoride, which can be in suspension in the aqueous medium. A
suspension of 15% by weight of calcium hydroxide in water is
introduced into the reactor (7) via the route (8). The reactor (7)
is maintained at a temperature of between 70 and 80.degree. C.
[0050] The outlet of the reactor (7) is connected to a filter (9),
in order to separate the calcium fluoride from the reaction medium
and then to wash it with water (10); the aqueous medium separated
from the calcium fluoride is subsequently recycled to the reactor
(1) after adjustment of the KOH concentration. The aqueous liquors
from washing the calcium fluoride are recycled to the tank (16) for
preparation of the suspension of calcium hydroxide in water.
[0051] The molten KOH mixture feeding the reactor (1) is prepared
by evaporation (removal of water (15)) of a 50% by weight aqueous
KOH solution (14) and of the aqueous solution originating from the
filter (9).
[0052] At the outlet of the reactor (1), the degree of molar
conversion of the 1,1,1,2,3,3-hexafluoropropane is greater than
98%. The selectivity for 1,1,1,2,3-pentafluoropropene is greater
than 99%.
[0053] At the outlet of the reactor (7), the degree of molar
conversion of the calcium hydroxide is greater than 85%.
Example 5
[0054] The operation is carried out at Example 4, except that the
reactor (1) is fed continuously with 1,1,1,2,3-pentafluoropropane
instead of 1,1,1,2,3,3-hexafluoropropane.
[0055] The stirred reactor (1) comprises a water and KOH mixture in
which the KOH is present at 65% by weight in the water.
[0056] At the outlet of the reactor (1), the degree of molar
conversion of the 1,1,1,2,3,-pentafluoropropane is greater than
98%. The selectivity for 1,1,1,2-tetrafluoropropene is greater than
99%.
Example 6
[0057] A reactor maintained at 80.degree. C. and stirred at 500
rev/min is fed continuously with a potassium hydroxide solution
resulting from the dehydrofluorination stage and assaying, after
dilution, 32.8% by weight of potassium hydroxide and 9.7% by weight
of KF. The Ca(OH).sub.2 suspension feeding the reactor assays 15%
by weight. The residence time in the reactor is approximately 1
h.
[0058] The ability to be filtered of the suspension obtained after
reaction is very good.
[0059] The level of solids of the suspension at the outlet of the
reactor is 3.6% by weight.
[0060] The particle size of the calcium fluoride synthesized is 30
pm and its purity is greater than 85% by weight.
* * * * *