Process for manufacturing epichlorohydrin
The present application claims benefit of French patent application n°
1058955 filed on October 29, 2010, the content of which is incorporated herein
by reference for all purposes.
Should the disclosure of any of the patents, patent applications, and
publications which are incorporated herein by reference conflict with the
description of the present application to the extent that it may render a term
unclear, the present description shall take precedence.
The present invention relates to a process for manufacturing
epichlorohydrin. The present invention relates more specifically to a process for
manufacturing epichlorohydrin that generates a mixture comprising
epichlorohydrin and water.
International application WO 2008/101866 filed in the name of SOLVAY
SA discloses a process for manufacturing epichlorohydrin via reaction between
dichloropropanol and a basic compound comprising a step of recovering, by
settling, the epichlorohydrin formed in the mixture resulting from the reaction
between the dichloropropanol and the basic compound. The conditions disclosed
for the settling operation do not make it possible to avoid a certain degradation of
the epichlorohydrin during this operation.
The present invention aims to overcome this problem by providing a
process for manufacturing epichlorohydrin, according to which:
(a) epichlorohydrin is prepared so as to obtain a mixture comprising
epichlorohydrin and water;
(b) the mixture obtained in step (a) is subjected to a liquid-liquid phase
separation so as to separate at least one first fraction (I) containing most of
the epichlorohydrin that was contained in the mixture obtained in step (a)
before the separation and at least one second fraction (II) containing most of
the water that was contained in the mixture obtained in step (a) before the
separation;
(c) fraction (I) and fraction (II) are drawn off;
in which the volume Vi of the fraction (I) obtained in step (b) expressed in m ,
the volume V of the fraction (II) obtained in step (b) expressed in m , the drawoff
flow rate Di of the fraction (I) in step (c) expressed in m /h and the draw-off
flow rate Dn of the fraction (II) in step (c) expressed in m /h, correspond to the
following formula:
(VII/VI) < (DII/DI)
Surprisingly, it has been observed that working under the volume and flow
rate conditions of the fractions of the process according to the invention has the
advantage of resulting in a better overall degree of recovery of the
epichlorohydrin. Without wishing to be tied to any one theoretical explanation,
it is believed that the fraction of epichlorohydrin recovered in fraction (I) and the
fraction of epichlorohydrin that can be recovered in fraction (II) are higher,
following limitation of the epichlorohydrin degradation reactions during the
phase separation step. The epichlorohydrin that can be recovered in fraction (II)
is the epichlorohydrin that can be recovered in subsequent treatment steps of
fraction (II). These degradation reactions are, for example, the hydrolysis
reactions of epichlorohydrin to monochloropropanediol and to glycerol.
In the process according to the invention, the ratio of the volumes (Vn/Vi)
is preferably less than or equal to 0.7 times the ratio of the flow rates (Dn/Di),
still preferably less than or equal to 0.5 times the ratio of the flow rates (Dn/Di),
more preferably less than or equal to 0.4 times the ratio of the flow rates (Dn/Di),
even more preferably less than or equal to 0.3 times the ratio of the flow rates
(DII/DI), more preferably still less than or equal to 0.2 times the ratio of the flow
rates (Dn/Di) and very particularly preferably less than 0.1 times the ratio of the
flow rates (Dn/Di).
In the process according to the invention, the ratio of the volumes (Vn/Vi)
is preferably greater than or equal to 0.005 times the ratio of the flow rates
(DII/DI), more preferably greater than or equal to 0.05 times the ratio of the flow
rates (Dn/Di) and very particularly preferably greater than or equal to 0 .1 times
this ratio of the flow rates (Dn/Di).
In the process according to the invention, the volume Vi of the fraction (I)
obtained in step (b) expressed in m , the volume V of the fraction (II) obtained
in step (b) expressed in m , the draw-off flow rate Di of the fraction (I) in step (c)
expressed in m /h and the draw-off flow rate Dn of the fraction (II) in step (c)
expressed in m /h, correspond to the following formula:
[(Vi + VII)/(DI + D )] < 10 h
In the process according to the invention, the sum of the volumes Vn and
Vi expressed in m3 is more preferably less than or equal to 5 times the sum of the
flow rates D and Di expressed in m /h, even more preferably less than or equal
to 2 times the sum of the flow rates Dn and Di, very particularly preferably less
than or equal to 1 times the sum of the flow rates Dn and Di, still very
particularly preferably less than or equal to 0.8 times the sum of the flow rates
DII and Di, yet very particularly preferably less than or equal to 0.5 times the sum
of the flow rates D and Di and most preferably less than or equal to 0.4 times
the sum of the flow rates Dn and Di.
In the process according to the invention, the sum of the volumes V and
Vi expressed in m is preferably greater than or equal to 0.001 times the sum of
the flow rates Dn and Di expressed in m /h, more preferably greater than or equal
to 0.01 times the sum of the flow rates Dn and Di, more preferably greater than
or equal to 0.05 times the sum of the flow rates Dn and Di and very particularly
preferably greater than or equal to 0 .1 times the sum of the flow rates Dn and Di.
In the process according to the invention, the mixture comprising
epichlorohydrin and water may originate from any manufacturing process.
Examples of such processes are the processes for manufacturing epichlorohydrin,
the processes for manufacturing a derivative of epichlorohydrin, in particular
epoxy resins, and combinations of at least two thereof. The derivatives of
epichlorohydrin and the epoxy resins may be as described in application
WO 2008/152044 filed in the name of SOLVAY (Societe Anonyme), of which
the content, and more specifically the passage from page 13, line 22, to page 44,
line 8, is incorporated herein by reference.
In the process according to the invention, the mixture comprising
epichlorohydrin and water preferably originates from a process for
manufacturing epichlorohydrin, from a process for manufacturing epoxy resins,
or from a combination of at least two of these processes.
In the process according to the invention, the mixture comprising
epichlorohydrin and water more preferably originates from a process for
manufacturing epichlorohydrin, even more preferably from a process for
manufacturing epichlorohydrin by dehydrochlorination of dichloropropanol, and
very particularly preferably from a process for manufacturing epichlorohydrin by
dehydrochlorination of dichloropropanol in which at least one portion of the
dichloropropanol was obtained from glycerol and of which at least one fraction
of said glycerol is natural glycerol. The dehydrochlorination of dichloropropanol
is preferably an alkaline dehydrochlorination. The expression "natural glycerol"
is understood to mean glycerol which has been obtained from renewable raw
materials. The natural glycerol is as described in application WO 2006/1003 12
in the name of SOLVAY (Societe Anonyme), of which the content, and more
specifically the passage from page 4, line 22, to page 5, line 24, is incorporated
herein by reference.
In the process according to the invention, at least one portion of the natural
glycerol was preferably obtained in the manufacture of biodiesel.
The processes for preparing dichloropropanol and epichlorohydrin can be
such as disclosed in International applications WO2005/054167,
WO2006/10031 1, WO2006/100312, WO2006/100313, WO2006/100314,
WO2006/100315, WO2006/100316, WO2006/100317, WO2006/106153,
WO2007/054505, WO 2006/100318, WO2006/100319, WO2006/100320, WO
2006/106154, WO2006/106155, WO 2007/144335, WO 2008/107468, WO
2008/101866, WO 2008/145729, WO 2008/1 10588, WO 2008/152045, WO
2008/152043, WO 2009/000773, WO 2009/043796, WO 2009/121853, WO
2008/152044, WO 2009/077528, WO 2010/066660, WO 2010/029039, WO
2010/029153, WO 201 1/054769 and WO 201 1/054770, filed in the name of
SOLVAY, the contents of which are incorporated herein by reference.
In the process according to the invention, the mixture obtained in step (a)
comprises epichlorohydrin, water and preferably at least one salt.
In the process according to the invention, the mixture obtained in step (a)
preferably comprises, in addition, at least one salt.
In the process according to the invention, when the mixture comprises
epichlorohydrin, water and at least one salt, this mixture more preferably
originates from a process for manufacturing epichlorohydrin as described in
application WO 2008/101866 in the name of SOLVAY (Societe Anonyme), of
which the content, and more specifically the passage from page 2, line 4, to page
6, line 21, is incorporated herein by reference.
In the process according to the invention, when the mixture comprises
epichlorohydrin, water and at least one salt, this mixture more preferably
originates from a process for manufacturing epichlorohydrin, even more
preferably from a process for manufacturing epichlorohydrin by
dehydrochlorination of dichloropropanol, and very particularly preferably from a
process for manufacturing epichlorohydrin by dehydrochlorination of
dichloropropanol in which at least one portion of the dichloropropanol was
obtained from glycerol and of which at least one fraction of said glycerol is
natural glycerol.
In the process according to the invention, the mixture from step (a)
comprises epichlorohydrin at a content generally greater than or equal to 10 g of
epichlorohydrin per kg of mixture, preferably greater than or equal to 30 g/kg,
more preferably greater than or equal to 50 g/kg, even more preferably greater
than or equal to 70 g/kg, more preferably still greater than or equal to 100 g/kg,
particularly preferably greater than or equal to 150 g/kg and more particularly
preferably greater than or equal to 170 g/kg and very particularly preferably
greater than or equal to 200 g/kg. This epichlorohydrin content is generally less
than or equal to 800 g of epichlorohydrin per kg of mixture, preferably less than
600 g/kg, more preferably less than or equal to 400 g/kg, even more preferably
less than or equal to 500 g/kg, and very particularly preferably less than or equal
to 350 g/kg.
In the process according to the invention, the mixture from step (a)
comprises water at a content generally greater than or equal to 20 g of water per
kg of mixture, preferably greater than 50 g/kg, more preferably greater than or
equal to 100 g/kg, even more preferably greater than or equal to 200 g/kg and
very particularly preferably greater than or equal to 300 g/kg. This water content
is generally less than or equal to 900 g of water per kg of mixture, preferably less
than 800 g/kg, more preferably less than or equal to 700 g/kg, even more
preferably less than or equal to 650 g/kg and very particularly preferably less
than or equal to 600 g/kg.
In the process according to the invention, when the mixture from step (a)
comprises at least one salt, the salt content is generally greater than or equal to
1 g of salt per kg of mixture, preferably greater than 10 g/kg, more preferably
greater than or equal to 50 g/kg, even more preferably greater than or equal to
80 g/kg, very particularly preferably greater than or equal to 90 g/kg and most
preferably greater than or equal to 120 g/kg. This salt content is generally less
than or equal to 250 g of salt per kg of mixture, preferably less than 220 g/kg,
more preferably less than or equal to 200 g/kg, even more preferably less than or
equal to 180 g/kg and very particularly preferably less than or equal to 160 g/kg.
In the process according to the invention, when the mixture from step (a)
comprises at least one salt, the salt may be an organic salt, an inorganic salt or a
mixture of the two. An inorganic salt is a salt whose constituent anions and
cations do not contain a carbon-hydrogen bond. The inorganic salt may be
chosen from the group constituted of metal chlorides, metal sulphates, metal
hydrogen sulphates, metal hydroxides, metal carbonates, metal hydrogen
carbonates, metal phosphates, metal hydrogen phosphates, metal borates and
mixtures of at least two thereof. Alkali and alkaline-earth metal chlorides are
preferred. Sodium and potassium chlorides are more particularly preferred and
sodium chloride is very particularly preferred.
In the process according to the invention, the mixture comprising
epichlorohydrin and water may contain at least one compound other than the
epichlorohydrin, the water and a salt. This compound may be as described for
the liquid reaction medium in application WO 2008/101866 in the name of
SOLVAY (Societe Anonyme), of which the content, and more specifically the
passage from page 6, line 22, to page 7, line 16, is incorporated herein by
reference. This other compound is, for example, a derivative of the
epichlorohydrin manufacturing process, and may be found in the group
constituted of dichloropropanols, glycerol, monochloropropanediols, glycerol
esters, esters of monochloropropanediols, esters of dichloropropanols, partially
chlorinated and/or esterified glycerol oligomers, aldehydes such as acrolein,
ketones such as chloracetone, chloroethers, basic compounds, acid compounds
such as hydrogen chloride, fatty acids, and mixtures of at least two thereof. The
at least one compound other than the epichlorohydrin, the water and a salt, is
preferably dichloropropanol.
In the process according to the invention, when the mixture from step (a)
comprises dichloropropanol, the dichloropropanol content is generally greater
than or equal to 1 g of dichloropropanol per kg of mixture, preferably greater
than 10 g/kg and more preferably greater than or equal to 50 g/kg. This
dichloropropanol content is generally less than or equal to 200 g of
dichloropropanol per kg of mixture, preferably less than 150 g/kg, more
preferably less than or equal to 100 g/kg and even more preferably less than or
equal to 75 g/kg.
This other compound may be a basic compound, for example when the
mixture containing epichlorohydrin, water and preferably at least one salt is
obtained by dehydrochlorination of dichloropropanol. This basic compound may
be an organic basic compound or an inorganic basic compound or a mixture of
the two. Organic basic compounds are, for example, amines, such as for
example imidazole and derivatives thereof, pyridine and derivatives thereof,
phosphines and ammonium, phosphonium or arsonium hydroxides. Inorganic
basic compounds are preferred. The expression "inorganic compounds" is
understood to mean compounds which do not contain a carbon-hydrogen bond.
The inorganic basic compound may be chosen from alkali metal oxides,
hydroxides, carbonates, hydrogen carbonates, phosphates, hydrogen phosphates
and borates, alkaline-earth metal oxides, hydroxides, carbonates, hydrogen
carbonates, phosphates, hydrogen phosphates and borates, and mixtures of at
least two thereof. Alkali metal oxides, alkali metal hydroxides, alkaline-earth
metal oxides, alkaline-earth metal hydroxides, and mixtures of at least two
thereof, are preferred. Sodium hydroxide, calcium hydroxide and mixtures
thereof are preferred. Sodium hydroxide is particularly preferred.
In one particular embodiment of the process according to the invention, the
pH of the mixture obtained in step (a) is controlled and maintained at a value
generally greater than or equal to 4, often greater than or equal to 5 and
frequently greater than or equal to 6 . This pH is controlled and maintained at a
value generally less than or equal to 10, often less than or equal to 9 and
frequently less than or equal to 8 .
In the process according to the invention, step (b) is generally carried out
in a liquid-liquid phase separation zone. Often, at least one liquid-liquid phase
separation zone is fed with the mixture from (a). The expression "separation
zone" is understood to mean the zone between feeding the mixture and drawing
off the first fraction (I), containing most of the epichlorohydrin that was
contained in the mixture obtained in step (a) before the separation, and the
second fraction (II) containing most of the water, and optionally salt, which were
contained in the mixture obtained in step (a) before the separation. The liquidliquid
phase separation zone may consist of any type of equipment that makes it
possible to carry out a liquid-liquid separation. Such equipment is, for example,
described in Perry's Chemical Engineers' Handbook, Sixth Edition, McGraw
Hill, 1984, Section 21-64 and 21-68.
In the process according to the invention, the mixture comprising
epichlorohydrin, water and optionally at least one salt preferably feeds a single
phase separation zone, and more specifically, this zone preferably consists of a
gravity-type separator. The gravity separator may be of assisted or unassisted
type. When the gravity separator is of assisted type, the assistance to the
gravitation may be chosen from the group constituted of centrifugal force,
pulsation, coalescence, plates and combinations of at least two thereof.
Examples of a centrifugal force-assisted gravity separator are a centrifugal dryer,
a centrifuge and a stirred column. An example of a pulsation-assisted gravity
separator is a pulsed column. An example of a coalescence-assisted gravity
separator is a settler/coalescer. An example of a plate-assisted gravity separator
is a plate settler. In the latter case, the plates reduce the settling height. The
separator is preferably chosen from the group constituted of a gravity settling
tank, a settler/coalescer, a plate settler and combinations of at least two thereof.
The separator is more preferably chosen from the group constituted of a gravity
settling tank, a settler/coalescer and combinations thereof. The separator is more
preferably a gravity settling tank.
In the process according to the invention, the liquid-liquid phase separation
is carried out at a temperature generally greater than or equal to 0°C, often
greater than or equal to 5°C, frequently greater than or equal to 10°C, in a lot of
cases greater than or equal to 20°C and in particular greater than or equal to
40°C. This temperature is generally less than or equal to 100°C, often less than
or equal to 85°C, frequently less than or equal to 75°C and in a lot of cases less
than or equal to 50°C.
In the process according to the invention, the pressure in the phase
separation zone is generally greater than or equal to 0.01 bar absolute, often
greater than or equal to 0.1 bar absolute, frequently greater than or equal to
0 .15 bar absolute, in a lot of cases greater than or equal to 0.2 bar absolute and in
particular greater than or equal to 0.6 bar absolute. This pressure is generally less
than or equal to 20 bar absolute, often less than or equal to 15 bar absolute,
frequently less than or equal to 10 bar absolute and in a lot of cases less than or
equal to 1.5 bar absolute.
In the process according to the invention, the separation of fractions (I) and
(II) is preferably carried out by unassisted gravitation or by centrifugal forceassisted
gravitation or by coalescence-assisted gravitation, preferably by
unassisted gravitation or by coalescence-assisted gravitation, and more
preferably by unassisted gravitation. The separation may be facilitated by the
use of any physical or chemical means or combinations thereof. The physical
means may be of static or mechanical type or may combine the two types. A
static physical means is, for example, the use of a static coalescing bed. A
dynamic physical means is, for example, the use of controlled stirring. The
chemical means are, for example, means that reduce the interfacial tension
between the fractions to be separated or that increase the difference in density
between fractions to be separated or that reduce the viscosity of the phases to be
separated.
In the process according to the invention, when the mixture obtained in
step (a) originates partly from a process for manufacturing epichlorohydrin by
dehydrochlorination of dichloropropanol, it is possible to add dichloropropanol
to the mixture obtained in step (a) so as to facilitate the phase separation of
step (b).
In the process according to the invention, when the mixture obtained in
step (a) originates partly from a process for manufacturing epichlorohydrin by
alkaline dehydrochlorination of dichloropropanol, it is possible to add
dichloropropanol to the mixture obtained in step (a) so as to facilitate the phase
separation of step (b).
In the process according to the invention, when the mixture obtained in
step (a) originates partly from a process for manufacturing epichlorohydrin by
alkaline dehydrochlorination of dichloropropanol and in which at least one
portion of the dichloropropanol was obtained from glycerol and of which at least
one fraction of the glycerol is natural glycerol, it is possible to add
dichloropropanol to the mixture obtained in step (a) so as to facilitate the phase
separation of step (b).
In the process according to the invention, the difference in density between
the fractions (I) and (II) is generally greater than or equal to 0.001, often greater
than or equal to 0.002, frequently greater than or equal to 0.01 and in a lot of
cases greater than or equal to 0.05. This difference in density is habitually less
than or equal to 0.4, often less than or equal to 0.2 and frequently less than or
equal to 0.1.
In the process according to the invention, the epichlorohydrin content in
fraction (I) is generally greater than or equal to 600 g of epichlorohydrin per kg
of fraction (I) and often greater than or equal to 700 g/kg. This content is usually
less than or equal to 950 g of epichlorohydrin per kg of fraction (I) and often less
than or equal to 800 g/kg.
In the process according to the invention, when the mixture from step (a)
comprises at least one salt, the salt content in fraction (II) is generally greater
than or equal to 5 g of salt per kg of fraction (II), usually greater than or equal to
30 g/kg, often greater than or equal to 50 g/kg, in a lot of cases greater than or
equal to 100 g/kg and frequently greater than or equal to 150 g/kg. This salt
content is usually less than or equal to 270 g of salt per kg of fraction (II),
generally less than or equal to 250 g, in a lot of cases less than or equal to 240
g/kg, frequently less than or equal to 220 g/kg and often less than or equal to 200
g/kg.
In the process according to the invention, the water content in fraction (II)
is generally greater than or equal to 700 g of water per kg of fraction (II), usually
greater than or equal to 720 g/kg, frequently greater than or equal to 740 g/kg
and often greater than or equal to 750 g/kg. This water content is usually less
than or equal to 995 g of water per kg of fraction (II), usually less than or equal
to 950 g/kg, frequently less than or equal to 900 g/kg and often less than or equal
to 850 g/kg.
In the process according to the invention, the volumes Vi and V of
fractions (I) and (II) may be adjusted by any means. It is possible, for example,
to independently adjust the total height of liquid in the phase separation zone and
the height of the interface between fractions (I) and (II).
The total height of liquid may, for example, be adjusted by setting the
overflow level of the phase separation zone with a dip tube or with a bottom
valve coupled to a level detector. This level detector may be based on any type
of level measurement method, such as hydrostatic methods with a float, plunger,
electromagnetic sensor, pressure sensor or bubble sensor, electrical level
measurement methods with conductive probes or capacitive probes and methods
based on the use of radiation with ultrasonic probes, radar and optical probes.
The height of the interface may be adjusted for example using an
adjustable gooseneck or via differential level measurements using the methods
described above.
In the process according to the invention, a preferred way of adjusting the
volumes Vi and Vn consists in adjusting the total height of liquid in the
separation zone via an overflow and the height of the interface between fractions
(I) and (II) via a bottom valve coupled to a level detector.
In the process according to the invention, the draw-off flow rates Di and
DII of fractions (I) and (II) may be adjusted by any means for measuring liquid
flow rate coupled to any draw-off means. The means for measuring flow rate
are, for example, via thermal mass flow meters, Coriolis mass flow meters,
ultrasonic flow meters, electromagnetic flow meters, float flow meters,
differential pressure flow meters, volumetric flow meters, turbine flow meters
and vortex flow meters. The draw-off means are, for example, via pumps,
gravity feeds with a gooseneck or gravity feeds with a valve.
In the process according to the invention, a preferred way of adjusting the
draw-off flow rates Di and Dn is to use a gravity means for the light phase and a
gravity means with a valve for the heavy phase.
The fraction (I) drawn off in the process according to the invention may be
subjected to at least one subsequent treatment chosen from the group constituted
of dilution, concentration, evaporation, distillation, stripping, liquid/liquid
extraction and adsorption, and combinations of at least two thereof. This
treatment may be as described in application WO 2008/152045 in the name of
SOLVAY (Societe Anonyme), of which the content, and more specifically the
passage from page 17, line 20, to page 23, line 5, is incorporated herein by
reference.
The fraction (II) drawn off in the process according to the invention may
be subjected to at least one subsequent treatment chosen from the group
constituted of a physical treatment, a chemical treatment, a biological treatment,
and combinations of at least two thereof. The physical treatment may be chosen
from the group constituted of dilution, concentration, evaporation, distillation,
stripping, liquid/liquid extraction, filtration and adsorption operations, alone or
in combination. The chemical treatment may be chosen from the group
constituted of oxidation, reduction, neutralization, complexation and
precipitation operations, alone or in combination. The biological treatment may
be chosen from the group constituted of aerobic or anaerobic bacterial
treatments, alone or in combination. The bacteria may be free (activated sludge,
lagooning) or fixed (bacteria bed, planted filters, sand filters, biofilter) or else
biodiscs. These treatments may be as described in application WO
2008/152043 in the name of SOLVAY (Societe Anonyme), of which the content,
and more specifically the passage from page 11, line 13, to page 29, line 7, is
incorporated herein by reference.
Examples 1 to 12 below are intended to illustrate the invention without
however limiting it.
Example 1 (in accordance with the invention)
Introduced into a gravity settling tank are 1000 kg/h of a mixture of an
aqueous phase and of an organic phase containing 225 g of epichlorohydrin/kg,
62 g of dichloropropanol/kg and 140 g of NaCl/kg. The mixture has a pH of 7 .
The settling tank functions at 40°C and under autogenous pressure of the system.
The settling tank is design to have an hold up of the aqueous phase of 0.054 m
and an hold-up of the organic phase of 0.214 m . The flows and the
compositions of the phases leaving the settling tank are calculated using
ASPEN+ and Aspen Tech software, taking into account the hydrolysis reactions
that take place in each of the phases present. The epichlorohydrin loss by
chemical reaction at the outlet of the settling tank is calculated and the results are
given in table 1.
Example 2, 3, 4 and 9 (not in accordance with the invention)
The procedure from Example 1 is followed, except that the settling is carried out
so as to ensure a defined hold-up of the aqueous and the organic phase. The
epichlorohydrin loss by chemical reaction at the outlet of the settling tank is
calculated and the results are given in table 1.
Example 5, 6, 7 and 8 (in accordance with the invention)
The procedure from Example 1 is followed, except that the settling is carried out
so as to ensure a defined hold-up of the aqueous and the organic phase. The
epichlorohydrin loss by chemical reaction at the outlet of the settling tank is
calculated and the results are given in table 1.
Example 10 and 11 (in accordance with the invention)
The procedure from Example 1 is followed, except that the settling is carried out
at 30 °C so as to ensure a defined hold-up of the aqueous and the organic phase.
The epichlorohydrin loss by chemical reaction at the outlet of the settling tank is
calculated and the results are given in table 1.
Example 12 (not in accordance with the invention)
The procedure from Example 1 is followed, except that the settling is carried out
at 30 °C so as to ensure a defined hold-up of the aqueous and the organic phase.
Theepichlorohydrin loss by chemical reaction at the outlet of the settling tank is
calculated and the results are given in table 1.
C L A I M S
1. Process for manufacturing epichlorohydrin, according to which:
(a) epichlorohydrin is prepared so as to obtain a mixture comprising
epichlorohydrin and water;
(b) the mixture obtained in step (a) is subjected to a liquid-liquid phase
separation so as to separate at least one first fraction (I) containing most of
the epichlorohydrin that was contained in the mixture obtained in step (a)
before the separation and at least one second fraction (II) containing most of
the water that was contained in the mixture obtained in step (a) before the
separation;
(c) fraction (I) and fraction (II) are drawn off;
in which the volume Vi of the fraction (I) obtained in step (b) expressed in m ,
the volume V of the fraction (II) obtained in step (b) expressed in m , the drawoff
flow rate Di of the fraction (I) in step (c) expressed in m /h and the draw-off
flow rate Dn of the fraction (II) in step (c) expressed in m /h, correspond to the
following formula:
(VII/VI) < (D /D )
2 . Process according to Claim 1, in which:
(VII/VI) < 0.7 (DII/DI)
3 . Process according to Claim 2, in which:
(VII/VI) < 0.5 (DII/DI)
4 . Process according to Claim 3, in which:
(VII/VI) < 0 .1 (DII/DI)
5. Process according to any one of Claims 1 to 4, in which the volume Vi
of the fraction (I) obtained in step (b) expressed in m3, the volume Vn of the
fraction (II) obtained in step (b) expressed in m3, the draw-off flow rate Di of the
fraction (I) in step (c) expressed in m /h and the draw-off flow rate Dn of the
fraction (II) in step (c) expressed in m /h, correspond to the following formula:
[(Vi + VII)/(DI + D )] < 10 h
6 . Process according to Claim 5, in which
[(Vi + VII)/(DI + DII)] < 1 h
7 . Process according to Claim 6, in which
[(Vi + Vii)/(Di + Dn)] < 0.5 h
8 . Process according to any one of Claims 1 to 7, in which the mixture
obtained in step (a) contains, in addition, at least one salt.
9 . Process according to claim 8, in which the salt is sodium chloride and
the salt content in the mixture obtained in step (a) is greater than or equal to 120
g of NaCl per kg of mixture.
10. Process according to Claim 8 or 9, in which the salt is sodium chloride
and the salt content in fraction (II) is greater than or equal to 5 g of NaCl per kg
of fraction (II).
11. Process according to Claim 10, in which the sodium chloride content in
fraction (II) is greater than or equal to 50 g of NaCl per kg of fraction (II).
12. Process according to Claim 11, in which the sodium chloride content in
fraction (II) is greater than or equal to 150 g of NaCl per kg of fraction (II).
13. Process according to any one of Claims 1 to 12, in which the
epichlorohydrin content in the mixture obtained in step (a) is greater than or
equal to 200 g of epichlorohydrin per kg of mixture.
14. Process according to any one of Claims 1 to 13, in which the
epichlorohydrin content in fraction (I) is greater than or equal to 600 g of
epichlorohydrin per kg of fraction (I).
15. Process according to any one of Claims 1 to 14, in which the mixture
obtained in step (a) contains, in addition, dichloropropanol.
16. Process according to Claim 15, in which the dichloropropanol content
the mixture obtained in step (a) is greater than or equal to 50 g of
dichloropropanol per kg of mixture.
17. Process according to any one of Claims 1 to 16, in which the liquidliquid
phase separation of step (b) is carried out by unassisted gravitation.
18. Process according to any one of Claims 1 to 17, in which the difference
in density between the fractions drawn off (I) and (II) is greater than or equal to
O.OOland less than or equal to 0.4.
19. Process according to any one of Claims 1 to 18, in which the mixture
obtained in step (a) originates partly from a process for manufacturing
epichlorohydrin by alkaline dehydrochlorination of dichloropropanol, and in
which at least one portion of the dichloropropanol was obtained from glycerol
and of which at least one fraction of the glycerol is natural glycerol.
20. Process according to Claim 19, in which dichloropropanol is added to
the mixture obtained in step (a).
21. Process according to any one of Claims 1 to 20, in which the pH of the
mixture obtained in step (a) is controlled and maintained at a value greater than
or equal to 4 and less than or equal to 10.