US20080194850A1

US20080194850A1 - Method for Making an Epoxide Starting with a Polyhydroxylated Aliphatic Hydrocarbon and a Chlorinating Agent

Info

Publication number: US20080194850A1
Application number: US11/915,046
Authority: US
Inventors: Philippe Krafft; Patrick Gilbeau; Dominique Balthasart; Valentine Smets
Original assignee: Solvay SA
Current assignee: Solvay SA
Priority date: 2005-05-20
Filing date: 2006-05-19
Publication date: 2008-08-14
Also published as: EA018478B1; EP2275417A2; US7615670B2; TWI320036B; EA200702552A1; EA200702553A1; JP2008540615A; BRPI0610744A2; WO2006100313A3; WO2006100314A1; BRPI0610748A2; EP1885673B1; EA017149B1; EP2284162B1; EA200702549A1; WO2006100311A3; MY148378A; JP2008545640A; KR101337048B1; CN101031532B

Abstract

Process for preparing an epoxide, wherein a reaction medium resulting from the reaction of a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof with a chlorinating agent, the reaction medium containing at least 10 g of chlorohydrin per kg of reaction medium, is subjected to a subsequent chemical reaction without intermediate treatment.

Description

The present patent application claims the benefit of patent application FR 05.05120 and of patent application EP 05104321.4, both filed on 20 May 2005, and of provisional U.S. patent applications 60/734,659, 60/734,627, 60/734,657, 60/734,658, 60/734,635, 60/734,634, 60/734,637 and 60/734,636, all filed on 8 Nov. 2005, the content of which is incorporated here by reference.
The present invention relates to a process for preparing an epoxide. Epoxides are important raw materials for the production of other compounds.
Ethylene oxide is used, for example, for the production of ethylene glycol, of di- and polyethylene glycols, of mono-, di- and triethanolamines, etc. (see K. Weissermel and H.-J. Arpe in Industrial Organic Chemistry, Third, Completely Revised Edition, VCH, 1997, page 149). Propylene oxide is an important intermediate in the preparation of propylene 1,2-glycol, of dipropylene glycol, of ethers of propylene glycol, of isopropylamines, etc. (see K. Weissermel and H.-J. Arpe in Industrial Organic Chemistry, Third, Completely Revised Edition, VCH, 1997, page 275). Epichlorohydrin is an important raw material for the production of glycerol, of epoxy resins, of synthetic elastomers, of glycidyl ethers, of polyamide resins, etc. (see Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition, Vol. A9, p. 539).
In the industrial production of propylene oxide the most commonly used technology comprises the following steps: hypochlorination of propylene to monochloropropanol and dehydrochlorination of the monochloropropanol to propylene oxide by means of an aqueous alkaline solution.
In the industrial production of epichlorohydrin the most commonly used technology comprises the following steps: high-temperature free-radical substitutive chlorination of propylene to allyl chloride, hypochlorination of the allyl chloride thus synthesized to dichloropropanol, and dehydrochlorination of the dichloropropanol to epichlorohydrin by means of an aqueous alkaline solution. Another technology, used on a smaller scale, comprises the following steps: catalytic acetoxylation of propylene to allyl acetate, hydrolysis of the allyl acetate to allyl alcohol, catalytic chlorination of the allyl alcohol to dichloropropanol, and alkaline dehydrochlorination of the dichloropropanol to epichlorohydrin. Other technologies, which have not yet gained industrial application, may be considered, including the direct catalytic oxidation of allyl chloride to epichlorohydrin using hydrogen peroxide, or the chlorination of glycerol to dichloropropanol, followed by alkaline dehydrochlorination of the dichloropropanol thus formed to epichlorohydrin.
Application WO 2005/054167 of SOLVAY SA describes a process for preparing dichloropropanol by reacting glycerol with hydrogen chloride in the presence of an organic acid as catalyst. In that process the dichloropropanol is separated from the other products of the reaction, the hydrogen chloride and the organic acid and the dichloropropanol is subjected to a dehydrochlorination reaction so as to give reaction products containing epichlorohydrin. The dehydrochlorination may be carried out in the presence of a basic agent and, in particular, of an aqueous solution of a basic agent. The separation of the organic acid is inconvenient if it forms an azeotrope with water or if its relative volatility is significant in the ternary water/dichloropropanol/hydrogen chloride mixture, and in that case the dichloropropanol is also contaminated with the esters that it forms with the organic acid.
The objective of the present invention is to provide a process for preparing an epoxide that does not exhibit these drawbacks.
The invention accordingly provides a process for preparing an epoxide, wherein a reaction medium resulting from the reaction of a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof with a chlorinating agent, the reaction medium containing at least 10 g of chlorohydrin per kg of reaction medium, is subjected to a subsequent chemical reaction without intermediate treatment.
The subsequent chemical reaction is preferably a dehydrochlorination reaction.
The dehydrochlorination reaction is preferably carried out by adding a basic compound to the reaction medium.
The invention more specifically provides a process for preparing an epoxide, comprising the following steps:

- (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is reacted with a chlorinating agent and an organic acid so as to form the chlorohydrin and chlorohydrin esters in a reaction medium containing the polyhydroxylated aliphatic hydrocarbon, the ester of a polyhydroxylated aliphatic hydrocarbon, water, the chlorinating agent and the organic acid, the reaction medium containing at least 10 g of chlorohydrin per kg of reaction medium,
- (b) at least a fraction of the reaction medium obtained in step (a), this fraction having the same composition as the reaction medium obtained in step (a), is subjected to one or more treatments in steps subsequent to step (a),
- (c) a basic compound is added to at least one of the steps subsequent to step (a), in order to react with the chlorohydrin, the chlorohydrin esters, the chlorinating agent and the organic acid, so as to form the epoxide and salts.

It has now been found that separating the organic acid and its derivatives is not indispensable, since by subjecting a mixture containing the chlorohydrin, the chlorinating agent and an organic acid to a reaction with a basic compound it is possible to produce an epoxide with an excellent yield. Surprisingly, the formation of salts resulting from the neutralization of the chlorinating agent and of the organic acid by the basic compound, and the hydrolysis of the esters formed between the chlorohydrin and the organic acid, do not disrupt the process for preparing the epoxide, even when substantial quantities of organic acid are present in the step of reaction (c) with the basic compound. A significant advantage of the process is that it is not necessary to separate the chlorinating agent and the organic acid that are used in the step of preparing the chlorohydrin.
The term “epoxide” is used here to describe a compound containing at least one oxygen bridged on a carbon-carbon bond. In general the carbon atoms of the carbon-carbon bond are adjacent and the compound may contain atoms other than carbon and oxygen atoms, such as hydrogen atoms and halogens. The preferred epoxides are ethylene oxide, propylene oxide, glycidol and epichlorohydrin, and mixtures of at least two thereof.
The term “olefin” is used here to describe a compound containing at least one carbon-carbon double bond. In general the compound may contain atoms other than carbon atoms, such as hydrogen atoms and halogens. The preferred olefins are ethylene, propylene, allyl chloride and mixtures of at least two thereof.
The term “polyhydroxylated aliphatic hydrocarbon” refers to a hydrocarbon which contains at least two hydroxyl groups attached to two different saturated carbon atoms. The polyhydroxylated aliphatic hydrocarbon may contain, but is not limited to, from 2 to 60 carbon atoms.
Each of the carbons of a polyhydroxylated aliphatic hydrocarbon carrying the hydroxyl (OH) functional group may not possess more than one OH group and must be of sp3 hybridization. The carbon atom carrying the OH group may be primary, secondary or tertiary. The polyhydroxylated aliphatic hydrocarbon used in the present invention must contain at least two sp3-hybridized carbon atoms carrying an OH group. The polyhydroxylated aliphatic hydrocarbon includes any hydrocarbon containing a vicinal diol (1,2-diol) or a vicinal triol (1,2,3-triol), including higher orders of these repeating units, which are vicinal or contiguous. The definition of the polyhydroxylated aliphatic hydrocarbon also includes, for example, one or more 1,3-, 1,4-, 1,5- and 1,6-diol functional groups. The polyhydroxylated aliphatic hydrocarbon may also be a polymer such as polyvinyl alcohol. Geminal diols, for example, are excluded from this class of polyhydroxylated aliphatic hydrocarbons.
The polyhydroxylated aliphatic hydrocarbons may contain aromatic moieties or heteroatoms including, for example, heteroatoms of halogen, sulphur, phosphorus, nitrogen, oxygen, silicon and boron type, and mixtures thereof.
Polyhydroxylated aliphatic hydrocarbons which can be used in the present invention include, for example, 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), 1,3-propanediol, 1-chloro-2,3-propanediol (chloropropanediol), 2-chloro-1,3-propanediol (chloropropanediol), 1,4-butanediol, 1,5-pentanediol, cyclohexanediols, 1,2-butanediol, 1,2-cyclohexanedimethanol, 1,2,3-propanetriol (also known as glycerol or glycerin), and mixtures thereof. With preference the polyhydroxylated aliphatic hydrocarbon used in the present invention includes, for example, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, chloropropanediol and 1,2,3-propanetriol, and mixtures of at least two thereof. More preferably the polyhydroxylated aliphatic hydrocarbon used in the present invention includes, for example, 1,2-ethanediol, 1,2-propanediol, chloropropanediol and 1,2,3-propanetriol and mixtures of at least two thereof. 1,2,3-Propanetriol, or glycerol, is the most preferred.
The esters of the polyhydroxylated aliphatic hydrocarbon may be present in the polyhydroxylated aliphatic hydrocarbon and/or may be produced in the process of preparing the chlorohydrin and/or may be prepared prior to the process of preparing the chlorohydrin. Examples of esters of polyhydroxylated aliphatic hydrocarbon include ethylene glycol monoacetate, propanediol monoacetates, glycerol monoacetates, glycerol monostearates, glycerol diacetates and mixtures thereof.
The term “chlorohydrin” is used here to describe a compound containing at least one hydroxyl group and at least one chlorine atom which are attached to different saturated carbon atoms. A chlorohydrin which contains at least two hydroxyl groups is also a polyhydroxylated aliphatic hydrocarbon. Hence the starting material and the product of the reaction may each be chlorohydrins. In that case the “product” chlorohydrin is more chlorinated than the starting chlorohydrin; in other words, it has more chlorine atoms and fewer hydroxyl groups than the starting chlorohydrin. Preferred chlorohydrins are chloroethanol, chloropropanol, chloropropanediol, dichloropropanol and mixtures of at least two thereof. Dichloropropanol is particularly preferred. Chlorohydrins which are more particularly preferred are 2-chloroethanol, 1-chloropropan-2-ol, 2-chloro-propan-1-ol, 1-chloropropane-2,3-diol, 2-chloropropane-1,3-diol, 1,3-dichloro-propan-2-ol, 2,3-dichloropropan-1-ol and mixtures of at least two thereof.
The polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon, and mixtures thereof, and the chlorohydrin in the process according to the invention may be obtained starting from fossil raw materials or starting from renewable raw materials, preferably starting from renewable raw materials.
By fossil raw materials are meant materials obtained from the treatment of petrochemical natural resources, for example petroleum, natural gas and coal. Among these materials the organic compounds containing 2 and 3 carbon atoms are preferred. When the chlorohydrin is dichloropropanol or chloropropanediol, allyl chloride, allyl alcohol and “synthetic” glycerol are particularly preferred. By “synthetic” glycerol is meant a glycerol obtained generally starting from petrochemical resources. When the chlorohydrin is chloroethanol, ethylene and “synthetic” ethylene glycol are particularly preferred. By “synthetic” ethylene glycol is meant an ethylene glycol obtained generally starting from petrochemical resources. When the chlorohydrin is monochloropropanol, propylene and “synthetic” propylene glycol are particularly preferred. By “synthetic” propylene glycol is meant a propylene glycol obtained generally starting from petrochemical resources.
By renewable raw materials are meant materials obtained from the treatment of renewable natural resources. Among these materials “natural” ethylene glycol, “natural” propylene glycol and “natural” glycerol are preferred. “Natural” ethylene glycol, propylene glycol and glycerol are obtained, for example, by conversion of sugars via thermochemical processes, it being possible for these sugars to be obtained starting from biomass, as described in “Industrial Bioproducts: Today and Tomorrow”, Energetics, Incorporated for the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Office of the Biomass Program, July 2003, pages 49, 52 to 56. One of these processes is, for example, the catalytic hydrogenolysis of sorbitol obtained by thermochemical conversion of glucose. Another process is, for example, the catalytic hydrogenolysis of xylitol obtained by hydrogenating xylose. The xylose may be obtained, for example, by hydrolyzing the hemicellulose present in maize fibres. By “natural glycerol” or by “glycerol obtained starting from renewable raw materials” is meant, in particular, glycerol obtained during the production of biodiesel or else glycerol obtained in the course of conversions of animal or vegetable oils or fats in general, such as saponification, transesterification or hydrolysis reactions.
Among the oils which can be used for preparing the natural glycerol mention may be made of all customary oils, such as palm oil, palm kernel oil, copra oil, babassu oil, former or new (low erucic acid) colza, sunflower oil, maize oil, castor oil and cotton oil, peanut oil, soyabean oil, linseed oil and crambe oil, and all oils obtained, for example, from sunflower or colza plants obtained by genetic modification or hybridization.
It is also possible to utilize used frying oils, various animal oils, such as fish oils, tallow, lard and even squaring greases.
Among the oils used it is also possible to indicate oils partially modified, for example, by polymerization or oligomerization, such as, for example, the stand oils of linseed oil and sunflower oil, and blown vegetable oils.
One particularly suitable glycerol may be obtained during the conversion of animal fats. Another particularly suitable glycerol may be obtained during the production of biodiesel. A third, very suitable glycerol may be obtained during the conversion of animal or vegetable oils or fats by transesterification in the presence of a heterogeneous catalyst, as described in documents FR 2752242, FR 2869612 and FR 2869613. More specifically, the heterogeneous catalyst is selected from mixed oxides of aluminum and zinc, mixed oxides of zinc and titanium, mixed oxides of zinc, titanium and aluminum, and mixed oxides of bismuth and aluminum, and the heterogeneous catalyst is employed in the form of a fixed bed. This latter process may be a biodiesel production process.
The chloroethanol may be obtained starting from these raw materials by any process. The processes of hypochlorinating ethylene and of chlorinating “synthetic” and/or “natural” ethylene glycol are preferred. The process of chlorinating “synthetic” and/or “natural” ethylene glycol is particularly preferred.
The chloropropanol may be obtained starting from these raw materials by any process. The processes of hypochlorinating propylene and chlorinating “synthetic” and/or “natural” propylene glycol are preferred. The process of chlorinating “synthetic” and/or “natural” propylene glycol is particularly preferred.
The chloropropanediol may be obtained starting from these raw materials by any process. The process of chlorinating “synthetic” and/or “natural” glycerol is preferred.
The dichloropropanol may be obtained starting from these raw materials by any process. The processes of hypochlorinating allyl chloride, chlorinating allyl alcohol and chlorinating “synthetic” and/or “natural” glycerol are preferred. The process of chlorinating “synthetic” and/or “natural” glycerol is particularly preferred.
In the process for preparing the epoxide according to the invention, it is preferable for at least a fraction of the chlorohydrin to be prepared by chlorinating a polyhydroxylated aliphatic hydrocarbon. The polyhydroxylated aliphatic hydrocarbon may be “synthetic” or “natural” in the senses defined above.
In the preparation process according to the invention, when the epoxide is epichlorohydrin, preference is given to “natural” glycerol, in other words glycerol obtained in the course of biodiesel production or in the course of conversions of animal or vegetable oils or fats, the conversions being selected from saponification, transesterification and hydrolysis reactions. Glycerol obtained by transesterification of fats or oils of vegetable or animal origin, the transesterification being carried out in the presence of a heterogeneous catalyst, is particularly preferred. In the process for preparing the epoxide according to the invention, the polyhydroxylated aliphatic hydrocarbon may be as described in the patent application entitled “Process for preparing chlorohydrin by converting polyhydroxylated aliphatic hydrocarbons”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing a chlorohydrin wherein a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof whose total metal content, the metals being expressed in the form of elements, is greater than or equal to 0.1 μg/kg and less than or equal to 1000 mg/kg, is reacted with a chlorinating agent.
In the process for preparing the epoxide according to the invention, the chlorohydrin obtained starting from the polyhydroxylated aliphatic hydrocarbon, from the ester of polyhydroxylated aliphatic hydrocarbon or from a mixture thereof by reaction with a chlorinating agent may be employed, for example, in accordance with the process described in application WO 2005/054167 of SOLVAY SA, the content of which is incorporated here by reference.
In the process for preparing the epoxide according to the invention, the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon and the mixtures thereof may be a crude product or a purified product as described in application WO 2005/054167 of SOLVAY SA, from page 2 line 8 to page 4 line 2.
In the process for preparing the epoxide according to the invention, the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon and the mixture thereof may have an alkali metal and/or alkaline earth metal content of less than or equal to 5 g/kg, as described in the application entitled “Process for preparing a chlorohydrin by chlorinating a polyhydroxylated aliphatic hydrocarbon”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
In the process according to the invention, the alkali metal and/or alkaline earth metal content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or a mixture thereof is less than or equal to 5 g/kg, often less than or equal to 1 g/kg, more particularly less than or equal to 0.5 g/kg and, in certain cases, less than or equal to 0.01 g/kg. The alkali metal and/or alkaline earth metal content of the glycerol is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the alkali metals are generally lithium, sodium, potassium and caesium, often sodium and potassium, and frequently sodium.
In the process for preparing a chlorohydrin according to the invention, the lithium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the sodium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the potassium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the rubidium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the caesium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the alkaline earth elements are generally magnesium, calcium, strontium and barium, often magnesium and calcium, and frequently calcium.
In the process according to the invention, the magnesium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the calcium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the strontium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the barium content of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is generally less than or equal to 1 g/kg, often less than or equal to 0.1 g/kg and more particularly less than or equal to 2 mg/kg. Said content is generally greater than or equal to 0.1 μg/kg.
In the process according to the invention, the alkali metals and/or alkaline earth metals are generally present in the form of salts, frequently in the form of chlorides, sulphates and mixtures thereof. Sodium chloride is the most often encountered.
In the process for preparing the epoxide according to the invention, the chlorinating agent of the polyhydroxylated aliphatic hydrocarbon, of the ester of polyhydroxylated aliphatic hydrocarbon or of the mixture thereof may be hydrogen chloride and/or hydrochloric acid as described in application WO 2005/054167 of SOLVAY SA, from page 4 line 30 to page 6 line 2.
Particular mention is made of a chlorinating agent which may be aqueous hydrochloric acid or hydrogen chloride which is preferably anhydrous. The hydrogen chloride may originate from a process for pyrolyzing organic chlorine compounds, such as, for example, a vinyl chloride preparation, a process for preparing 4,4-methylenediphenyl diisocyanate (MDI) or toluene diisocyanate (TDI), metal pickling processes, or the reaction of an inorganic acid such as sulphuric or phosphoric acid with a metal chloride such as sodium chloride, potassium chloride or calcium chloride.
In one advantageous embodiment of the process for preparing the epoxide according to the invention, the chlorinating agent of the polyhydroxylated aliphatic hydrocarbon, of the ester of polyhydroxylated aliphatic hydrocarbon or of the mixture thereof is gaseous hydrogen chloride or an aqueous solution of hydrogen chloride or a combination of the two.
In the process for preparing the epoxide according to the invention, the chlorinating agent of the polyhydroxylated aliphatic hydrocarbon, of the ester of polyhydroxylated aliphatic hydrocarbon or of the mixture thereof may be aqueous hydrochloric acid or hydrogen chloride, preferably anhydrous, obtained from a process for preparing allyl chloride and/or chloromethanes and/or of chlorinolysis and/or of high-temperature oxidation of chlorine compounds, as described in the application entitled “Process for preparing a chlorohydrin by reacting a polyhydroxylated aliphatic hydrocarbon with a chlorinating agent”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing a chlorohydrin from a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof and a chlorinating agent, the latter agent containing at least one of the following compounds: nitrogen, oxygen, hydrogen, chlorine, an organic hydrocarbon compound, an organic halogen compound, an organic oxygen compound and a metal.
Particular mention is made of an organic hydrocarbon compound selected from saturated or unsaturated aliphatic and aromatic hydrocarbons and mixtures thereof.
Particular mention is made of an unsaturated aliphatic hydrocarbon selected from acetylene, ethylene, propylene, butene, propadiene, methylacetylene and mixtures thereof, of a saturated aliphatic hydrocarbon selected from methane, ethane, propane, butane and mixtures thereof, and of an aromatic hydrocarbon which is benzene.
Particular mention is made of an organic halogen compound which is an organic chlorine compound selected from chloromethanes, chloroethanes, chloropropanes, chlorobutanes, vinyl chloride, vinylidene chloride, monochloropropenes, perchloroethylene, trichloroethylene, chlorobutadienes, chlorobenzenes and mixtures thereof.
Particular mention is made of an organic halogen compound which is an organic fluorine compound selected from fluoromethanes, fluoroethanes, vinyl fluoride, vinylidene fluoride and mixtures thereof.
Particular mention is made of an organic oxygen compound selected from alcohols, chloroalcohols, chloroethers and mixtures thereof.
Particular mention is made of a metal selected from alkali metals, alkaline earth metals, iron, nickel, copper, lead, arsenic, cobalt, titanium, cadmium, antimony, mercury, zinc, selenium, aluminum, bismuth and mixtures thereof.
Mention is made more particularly of a process wherein the chlorinating agent is obtained at least partly from a process for preparing allyl chloride and/or from a process for preparing chloromethanes and/or from a process of chlorinolysis and/or from a process of oxidizing chlorine compounds at a temperature greater than or equal to 800° C.
In one advantageous embodiment of the process for preparing the epoxide according to the invention, the chlorinating agent of the polyhydroxylated aliphatic hydrocarbon, of the ester of polyhydroxylated aliphatic hydrocarbon or of the mixture thereof contains no gaseous hydrogen chloride.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out in a reactor as described in application WO 2005/054167 of SOLVAY SA, at page 6 lines 3 to 23.
Mention is made particularly of plant made of or covered with materials which under the reaction conditions are resistant to chlorinating agents, especially to hydrogen chloride. Mention is made more particularly of plant made of enameled steel or of tantalum.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out in apparatus made of or covered with materials which are resistant to chlorinating agents, as described in the application entitled “Process for preparing a chlorohydrin in corrosion-resistant apparatus”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing a chlorohydrin which comprises a step wherein a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is subjected to reaction with a chlorinating agent containing hydrogen chloride and at least one other step carried out in apparatus made of or covered with materials resistant to the chlorinating agent under the conditions in which said step is performed. Mention is made more particularly of metallic materials such as enameled steel, gold and tantalum and of non-metallic materials such as high-density polyethylene, polypropylene, poly(vinylidene fluoride), polytetrafluoroethylene, perfluoroalkoxyalkanes and poly(perfluoropropyl vinyl ether), polysulphones and polysulphides, and graphite, including impregnated graphite.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out in a reaction medium as described in the application entitled “Continuous process for preparing chlorohydrins”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a continuous process for producing chlorohydrin wherein a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is reacted with a chlorinating agent and an organic acid in a liquid reaction medium whose steady-state composition comprises polyhydroxylated aliphatic hydrocarbon and esters of polyhydroxylated aliphatic hydrocarbon with a sum content, expressed in moles of polyhydroxylated aliphatic hydrocarbon, of more than 1.1 mol % and less than or equal to 30 mol %, the percentage being based on the organic part of the liquid reaction medium.
The organic part of the liquid reaction medium consists of all of the organic compounds in the liquid reaction medium, in other words the compounds whose molecule contains at least 1 carbon atom.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out in the presence of a catalyst as described in application WO 2005/054167 of SOLVAY SA, from page 6 line 28 to page 8 line 5.
Mention is made particularly of a catalyst based on a carboxylic acid or on a carboxylic acid derivative having an atmospheric boiling point of greater than or equal to 200° C., especially adipic acid and adipic acid derivatives.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out at a catalyst concentration, temperature and pressure and for residence times as described in application WO 2005/054167 of SOLVAY SA, from page 8 line 6 to page 10 line 10.
Mention is made particularly of a temperature of at least 20° C. and not more than 160° C., a pressure of at least 0.3 bar and not more than 100 bar and a residence time of at least 1 h and not more than 50 h.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out in the presence of a solvent as described in application WO 2005/054167 of SOLVAY SA, at page 11 lines 12 to 36.
Mention is made particularly of an organic solvent such as chlorinated organic solvent, an alcohol, a ketone, an ester or an ether, a non-aqueous solvent which is miscible with the polyhydroxylated aliphatic hydrocarbon, such as chloroethanol, chloropropanol, chloropropanediol, dichloropropanol, dioxane, phenol, cresol, and mixtures of chloropropanediol and dichloropropanol, or heavy reaction products such as at least partly chlorinated and/or esterified oligomers of the polyhydroxylated aliphatic hydrocarbon.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out in the presence of a liquid phase comprising heavy compounds other than the polyhydroxylated aliphatic hydrocarbon, as described in the application entitled “Process for preparing a chlorohydrin in a liquid phase”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing a chlorohydrin wherein a polyhydroxylated aliphatic hydrocarbon, an ester of polyhydroxylated aliphatic hydrocarbon or a mixture thereof is subjected to reaction with a chlorinating agent in the presence of a liquid phase comprising heavy compounds other than the polyhydroxylated aliphatic hydrocarbon, the boiling temperature of said compounds under a pressure of 1 bar absolute being at least 15° C. greater than the boiling temperature of the chlorohydrin under a pressure of 1 bar absolute.
In the process for preparing the epoxide according to the invention, the reaction of chlorinating the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof is preferably carried out in a liquid reaction medium. The liquid reaction medium may be single-phase or multi-phase.
The liquid reaction medium is composed of the entirety of the dissolved or dispersed solid compounds, dissolved or dispersed liquid compounds and dissolved or dispersed gaseous compounds at the reaction temperature.
The reaction medium comprises the reactants, the catalyst, the solvent, the impurities present in the reactants, in the solvent and in the catalyst, the reaction intermediates, the reaction products and the reaction by-products.
By reactants are meant the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon and the chlorinating agent.
The impurities present in the polyhydroxylated aliphatic hydrocarbon may include carboxylic acids, salts of carboxylic acids, fatty acid esters with the polyhydroxylated aliphatic hydrocarbon, fatty acid esters with the alcohols used in the transesterification, and inorganic salts such as alkali metal or alkaline earth metal sulphates and chlorides.
When the polyhydroxylated aliphatic hydrocarbon is glycerol, the impurities of the glycerol may include carboxylic acids, salts of carboxylic acids, fatty acid esters such as mono-, di- and triglycerides, fatty acid esters with the alcohols used in the transesterification, and inorganic salts such as alkali metal or alkaline earth metal sulphates and chlorides.
The reaction intermediates may include monochlorohydrins of the polyhydroxylated aliphatic hydrocarbon and their esters and/or polyesters, the esters and/or polyesters of the polyhydroxylated aliphatic hydrocarbon, and the esters of polychlorohydrins.
When the chlorohydrin is dichloropropanol, the reaction intermediates may include the monochlorohydrin of glycerol and its esters and/or polyesters, the esters and/or polyesters of glycerol, and the esters of dichloropropanol.
The ester of polyhydroxylated aliphatic hydrocarbon may therefore be, as appropriate, a reactant, an impurity of the polyhydroxylated aliphatic hydrocarbon or a reaction intermediate.
By reaction products are meant the chlorohydrin and water. The water may be the water formed in the chlorination reaction and/or may be the water introduced into the process, for example via the polyhydroxylated aliphatic hydrocarbon and/or the chlorinating agent, as described in application WO 2005/054167 of SOLVAY SA, at page 2 lines 22 to 28, at page 3 lines 20 to 25, at page 5 lines 7 to 31 and at page 12 lines 14 to 19.
The by-products may include, for example, partly chlorinated and/or esterified oligomers of the polyhydroxylated aliphatic hydrocarbon.
When the polyhydroxylated aliphatic hydrocarbon is glycerol, the by-products may include, for example, the partly chlorinated and/or esterified oligomers of glycerol.
The reaction intermediates and the by-products may be formed in the various steps of the process, such as, for example, during step (a) and during the treatment steps subsequent to step (b).
The liquid reaction medium may thus comprise the polyhydroxylated aliphatic hydrocarbon, the chlorinating agent, dissolved or dispersed in the form of bubbles, the catalyst, the solvent, the impurities present in the reactants, the solvent and the catalyst, such as dissolved or solid salts, for example, the reaction intermediates, the reaction products and the reaction by-products.
Steps (a), (b) and (c) of the process for preparing the epoxide according to the invention may be conducted independently in batch mode or in continuous mode. Continuous mode is preferred. Continuous mode for the 3 steps is particularly preferred.
In the preparation process according to the invention the organic acid may be a product originating from the process for preparing the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof, or a product not originating from that process. In this latter case, the organic acid may be an organic acid used to catalyze the reaction between the polyhydroxylated aliphatic hydrocarbon and the chlorinating agent. The organic acid may also be a mixture of organic acid originating from the process for preparing the polyhydroxylated aliphatic hydrocarbon and an organic acid not originating from the process for preparing the polyhydroxylated aliphatic hydrocarbon. Preference is given to using an organic acid which is not obtained during the preparation of the polyhydroxylated aliphatic hydrocarbon, this acid being used as a catalyst of the reaction between the polyhydroxylated aliphatic hydrocarbon and the chlorinating agent. Preference is given to using, in particular, acetic acid or adipic acid.
In the process according to the invention, the esters of the polyhydroxylated aliphatic hydrocarbon may originate from the reaction of the polyhydroxylated aliphatic hydrocarbon with an organic acid, before, during or within the steps which follow the reaction with the chlorinating agent.
In the process according to the invention, the chlorohydrin may be separated from the other compounds of the reaction medium in accordance with methods as described in application WO 2005/054167 of SOLVAY SA, from page 12 line 1 to page 16 line 35 and at page 18 lines 6 to 13. These other compounds are those mentioned above, and include unconsumed reactants, the impurities present in the reactants, the catalyst and the solvent, the solvent, the catalyst, the reaction intermediates, the water and the reaction by-products.
Particular mention is made of separation by azeotropic distillation of a water/chlorohydrin/chlorinating agent mixture under conditions which minimize the losses of chlorinating agent, followed by separation of the chlorohydrin by decantation.
In the process for preparing the epoxide according to the invention, the separation of the chlorohydrin and the other compounds from the reaction medium from chlorination of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out according to methods as described in patent application EP 05104321.4, filed in the name of SOLVAY SA on 20 May 2005, and the content of which is incorporated here by reference. A separation method including at least one separating operation intended to remove the salt from the liquid phase is particularly preferred.
Particular mention is made of a process for preparing a chlorohydrin by reacting a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof with a chlorinating agent wherein the polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof that is used contains at least one solid or dissolved metal salt, the process including a separating operation intended to remove part of the metal salt. Mention is made more particularly of a process for preparing a chlorohydrin by reacting a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon of a mixture thereof with a chlorinating agent wherein the polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof that is used contains at least one sodium and/or potassium chloride and/or sulphate and wherein the separating operation intended to remove part of the metal salt is a filtering operation. Mention is also made particularly of a process for preparing a chlorohydrin wherein (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is subjected to reaction with a chlorinating agent in a reaction mixture, (b) a fraction of the reaction mixture containing at least the water and the chlorohydrin is removed continuously or periodically, (c) at least one part of the fraction obtained in step (b) is introduced into a distillation step, and (d) the reflux ratio of the distillation step is controlled by supplying water to said distillation step. Mention is made very particularly of a process for preparing a chlorohydrin wherein (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is subjected to reaction with hydrogen chloride in a reaction mixture, (b) a fraction of the reaction mixture containing at least the water in the chlorohydrin is removed continuously or periodically, (c) at least part of the fraction obtained in step (b) is introduced into a distillation step, wherein the ratio between the hydrogen chloride concentration and the water concentration in the fraction introduced into the distillation step is smaller than the ratio of hydrogen chloride/water concentrations in the binary azeotropic hydrogen chloride/water composition at the distillation temperature and pressure.
In the process for preparing the epoxide according to the invention, the chlorohydrin and the other compounds can be separated from the reaction medium from chlorination of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof by methods as described in the application entitled “Process for preparing a chlorohydrin”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing a chlorohydrin comprising the following steps: (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is reacted with a chlorinating agent and an organic acid so as to give a mixture containing the chlorohydrin and esters of a chlorohydrin, (b) at least part of the mixture obtained in step (a) is subjected to one or more treatments in steps subsequent to step (a), and (c) polyhydroxylated aliphatic hydrocarbon is added to at least one of the steps subsequent to step (a), so as to react, at a temperature greater than or equal to 20° C., with the esters of the chlorohydrin, so as to form, at least partly, esters of the polyhydroxylated aliphatic hydrocarbon. Mention is made more particularly of a process wherein the polyhydroxylated aliphatic hydrocarbon is glycerol and the chlorohydrin is dichloropropanol.
In the process for preparing the epoxide according to the invention, the chlorohydrin and the other compounds can be separated from the reaction medium from chlorination of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof by methods as described in the application entitled “Process for preparing a chlorohydrin starting from a polyhydroxylated aliphatic hydrocarbon”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing chlorohydrin by reacting a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof with a chlorinating agent in a reactor which is supplied with one or more liquid streams containing less than 50% by weight of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated hydrocarbon or the mixture thereof, relative to the weight of the entirety of the liquid streams introduced into the reactor. More particular mention is made of a process comprising the following steps: (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is reacted with a chlorinating agent so as to give at least one mixture containing the chlorohydrin, water and the chlorinating agent, (b) at least a fraction of the mixture formed in step (a) is removed, and (c) the fraction removed in step (b) is subjected to a distilling and/or stripping operation wherein polyhydroxylated aliphatic hydrocarbon is added in order to separate, from the fraction removed in step (b), a mixture containing water and the chlorohydrin, having a reduced chlorinating agent content as compared with that of the fraction removed in step (b).
In the process for preparing the epoxide according to the invention, the chlorohydrin and the other compounds of the reaction medium from chlorination of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be separated by methods as described in the application entitled “Process for converting polyhydroxylated aliphatic hydrocarbons into chlorohydrins”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing a chlorohydrin comprising the following steps: (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is reacted with a chlorinating agent so as to give a mixture containing the chlorohydrin, chlorohydrin esters and water, (b) at least a fraction of the mixture obtained in step (a) is subjected to a distilling and/or stripping treatment so as to give a batch concentrated with water, with chlorohydrin and with chlorohydrin esters, and (c) at least a fraction of the batch obtained in step (b) is subjected to a separating operation in the presence of at least one additive so as to give a portion concentrated with chlorohydrin and with chlorohydrin esters and containing less than 40% by weight of water.
The separating operation is more particularly a decantation.
In the process for preparing the epoxide according to the invention, the separation and the treatment of the other compounds of the reaction medium from chlorination of the polyhydroxylated aliphatic hydrocarbon, the ester of polyhydroxylated aliphatic hydrocarbon or the mixture thereof may be carried out by methods as described in the application entitled “Process for preparing a chlorohydrin by chlorinating a polyhydroxylated aliphatic hydrocarbon”, filed in the name of SOLVAY SA on the same day as the present application. One preferred treatment consists in subjecting a fraction of the reaction by-products to a high-temperature oxidation.
Particular mention is made of a process for preparing a chlorohydrin comprising the following steps: (a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof whose alkali metal and/or alkaline earth metal content is less than or equal to 5 g/kg, a chlorinating agent and an organic acid are reacted so as to give a mixture containing at least the chlorohydrin and by-products, (b) at least part of the mixture obtained in step (a) is subjected to one or more treatments in steps subsequent to step (a), and (c) at least one of the steps subsequent to step (a) consists in an oxidation at a temperature greater than or equal to 800° C. More particular mention is made of a process wherein, in the subsequent step, a part of the mixture obtained in step (a) is removed and this part is subjected to oxidation at a temperature greater than or equal to 800° C. in the course of its removal. Particular mention is also made of a process wherein the treatment of step (b) is a separating operation selected from decantation, filtration, centrifugation, extraction, washing, evaporation, stripping, distillation and adsorption operations or combinations of at least two thereof.
In the process according to the invention, when the chorohydrin is chloropropanol, said chloropropanol is generally obtained in the form of a mixture of compounds comprising the isomers of 1-chloropropan-2-ol and of 2-chloropropan-1-ol. This mixture generally contains more than 1% by weight of the two isomers, preferably more than 5% by weight and in particular more than 50%. The mixture usually contains less than 99.9% by weight of the two isomers, preferably less than 95% by weight and very particularly less than 90% by weight. The other constituents of the mixture may be compounds originating from the processes for preparing the chloropropanol, such as residual reactants, reaction by-products, solvents and, in particular, water.
The mass ratio between the isomers 1-chloropropan-2-ol and 2-chloropropan-1-ol is usually greater than or equal to 0.01, preferably greater than or equal to 0.4. This ratio is usually less than or equal to 99 and preferably less than or equal to 25.
In the process according to the invention, when the chorohydrin is chloroethanol, said chloroethanol is generally obtained in the form of a mixture of compounds comprising the isomer 2-chloroethanol. This mixture generally contains more than 1% by weight of the isomer, preferably more than 5% by weight and in particular more than 50%. The mixture usually contains less than 99.9% by weight of the isomer, preferably less than 95% by weight and very particularly less than 90% by weight. The other constituents of the mixture may be compounds originating from the processes for preparing the chloroethanol, such as residual reactants, reaction by-products, solvents and, in particular, water.
In the process according to the invention, when the chlorohydrin is dichloropropanol, said dichloropropanol is generally obtained in the form of a mixture of compounds comprising the isomers of 1,3-dichloropropan-2-ol and of 2,3-dichloropropan-1-ol. This mixture generally contains more than 1% by weight of the two isomers, preferably more than 5% by weight and in particular more than 50%. The mixture usually contains less than 99.9% by weight of the two isomers, preferably less than 95% by weight and very particularly less than 90% by weight. The other constituents of the mixture may be compounds originating from the processes for preparing the dichloropropanol, such as residual reactants, reaction by-products, solvents and, in particular, water.
The mass ratio between the isomers 1,3-dichloropropan-2-ol and 2,3-dichloropropan-1-ol is usually greater than or equal to 0.01, often greater than or equal to 0.4, frequently greater than or equal to 1.5, preferably greater than or equal to 3.0, more preferably greater than or equal to 7.0 and, with very particular preference, greater than or equal to 20.0. This ratio is usually less than or equal to 99 and preferably less than or equal to 25.
In the process according to the invention, when the chlorohydrin is dichloropropanol and is obtained in a process starting from allyl chloride, the isomer mixture exhibits a 1,3-dichloropropan-2-ol:2,3-dichloropropan-1-ol mass ratio which is often from 0.3 to 0.6, typically approximately 0.5. When the dichloropropanol is obtained in a process starting from synthetic and/or natural glycerol, the 1,3-dichloropropan-2-ol:2,3-dichloropropan-1-ol mass ratio is commonly greater than or equal to 1.5, preferably greater than or equal to 3.0 and very particularly greater than or equal to 9.0. When the dichloropropanol is obtained starting from allyl alcohol, the 1,3-dichloropropan-2-ol:2,3-dichloropropan-1-ol mass ratio is often of the order of 0.1.
In the process according to the invention, when the chlorohydrin is dichloropropanol, the mixture of isomers exhibits a 1,3-dichloropropan-2-ol: 2,3-dichloropropan-1-ol mass ratio of generally greater than or equal to 0.5, often greater than or equal to 3 and frequently greater than or equal to 20.
In the process for preparing the epoxide according to the invention, the chlorohydrin may include a high halogenated ketone content, particularly of chloroacetone, as described in patent application FR 05.05120 of May 20, 2005, filed in the name of the applicant, and the content of which is incorporated here by reference. The halogenated ketone content may be reduced by subjecting the chlorohydrin obtained in the process according to the invention to an azeotropic distillation in the presence of water, or by subjecting the chlorohydrin to a dehydrochlorination treatment as described in this application, from page 4 line 1 to page 6 line 35.
Particular mention is made of a process for preparing an epoxide wherein halogenated ketones are formed as by-products, and which comprises at least one treatment for removing at least some of the halogenated ketones formed. Mention is made more particularly of a process for preparing an epoxide by dehydrochlorinating a chlorohydrin at least a fraction of which is prepared by chlorinating a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof, a dehydrochlorination treatment, and a treatment by azeotropic distillation of a water/halogenated ketone mixture, the intention of which is to remove at least some of the halogenated ketones formed, and a process for preparing epichlorohydrin wherein the halogenated ketone formed is chloroacetone.
In the process for preparing an epoxide according to the invention, the chlorohydrin may be subjected to a dehydrochlorination reaction to produce an epoxide as described in patent applications WO 2005/054167 and FR 05.05120, both filed in the name of SOLVAY SA.
In the process for preparing an epoxide according to the invention, the epoxide is formed during the reaction of dehydrochlorinating the chlorohydrin with the basic compound.
In a first embodiment of the process for preparing an epoxide according to the invention, a fraction of the reaction medium obtained in step (a) is withdrawn, this fraction having the same composition as the reaction medium obtained in step (a), and the basic compound is added to it during the withdrawal.
The chlorohydrin content of this fraction is generally greater than or equal to 10 g/kg, often greater than or equal to 400 g/kg and in particular greater than or equal to 500 g/kg. Said content is generally less than or equal to 750 g/kg, often less than or equal to 650 g/kg and in particular less than or equal to 600 g/kg.
The chlorinating agent content of the fraction of the mixture obtained in step (a) is generally greater than or equal to 10 g/kg, often greater than or equal to 20 g/kg and in particular greater than or equal to 30 g/kg. Said content is generally less than or equal to 150 g/kg, often less than or equal to 130 g/kg and in particular less than or equal to 100 g/kg.
The total organic acid content of the fraction of the mixture obtained in step (a) is generally greater than or equal to 1 g/kg, often greater than or equal to 2 g/kg and in particular greater than or equal to 5 g/kg. Said content is generally less than or equal to 40 g/kg, often less than or equal to 20 g/kg and in particular less than or equal to 10 g/kg. By total organic acid content is meant the sum of the amounts of organic acid per se, of esters of the organic acid and of salts of the organic acid, this sum being expressed as organic acid per se.
In a second embodiment of the process for preparing an epoxide according to the invention, a fraction of the medium obtained in step (a) is withdrawn, this fraction having the same composition as the reaction medium obtained in step (a), this fraction is subjected to one or more separation treatments, for example evaporation, stripping and/or distillation, so as to give a part enriched with chlorohydrin and with water.
The concentrations of the different species present in this part may vary greatly as a function in particular of the raw materials employed, for example the type of chlorinating agent, hydrogen chloride in anhydrous form or in aqueous solution, the water content of the polyhydroxylated aliphatic hydrocarbon or else the type of organic acid used as catalyst, or as a function of the separation treatment. Surprisingly the process according to the present invention may be employed in all of these cases.
The chlorohydrin content of the part enriched with chlorohydrin and with water is generally greater than or equal to 10 g/kg, often greater than or equal to 400 g/kg and in particular greater than or equal to 500 g/kg. Said content is generally less than or equal to 750 g/kg, often less than or equal to 600 g/kg and in particular less than or equal to 700 g/kg.
The chlorinating agent content of this part is generally greater than or equal to 10 g/kg, often greater than or equal to 20 g/kg and in particular greater than or equal to 30 g/kg. Said content is generally less than or equal to 150 g/kg, often less than or equal to 130 g/kg and in particular less than or equal to 100 g/kg.
The total organic acid content of this part is generally greater than or equal to 1 g/kg, often greater than or equal to 2 g/kg and in particular greater than or equal to 5 g/kg. Said content is generally less than or equal to 40 g/kg, often less than or equal to 25 g/kg and in particular less than or equal to 100 g/kg.
In a first variant of this second embodiment, the basic compound is added to this part enriched with chlorohydrin and with water.
In a second variant of this second embodiment, the part enriched with chlorohydrin and with water is subjected to a decantation so as to give a first portion enriched with water and a second portion enriched with chlorohydrin.
This decantation may be carried out, for example, in the reflux reservoir of a distillation column or at any desired subsequent stage, such as, for example, a stage of storage or of secondary distillation for the purposes of purification. The devices for carrying out this phase separation are described for example in Perry's Chemical Engineers' Handbook, Sixth Edition, Robert H. Perry, Don Green, 1984, sections 21-64 to 21-68.
The chlorohydrin, water and chlorinating agent contents in these two portions may be easily deduced from the ternary diagrams of the compositions of chlorohydrin/water/chlorinating agent mixtures. A ternary diagram of this kind for the 1,3-dichloropropanol/water/hydrogen chloride mixture may be found in G. P. Gibson, The preparation, properties, and uses of glycerol derivatives, Part III, The chlorohydrins, pages 970 to 975.
The first portion may contain the chlorohydrin. The chlorohydrin content is generally less than or equal to 300 g/kg, often less than or equal to 250 g/kg and in particular less than or equal to 200 g/kg.
The chlorinating agent content of this first portion is generally greater than or equal to 1 g/kg, often greater than or equal to 10 g/kg and in particular greater than or equal to 20 g/kg. Said content is generally less than or equal to 250 g/kg, often less than or equal to 200 g/kg and in particular less than or equal to 150 g/kg.
The total organic acid content of this first portion is generally greater than or equal to 1 g/kg, often greater than or equal to 2 g/kg and in particular greater than or equal to 3 g/kg. Said content is generally less than or equal to 100 g/kg, often less than or equal to 50 g/kg and in particular less than or equal to 30 g/kg.
The chlorohydrin content of the second portion is generally greater than or equal to 600 g/kg, often greater than or equal to 700 g/kg and in particular greater than or equal to 800 g/kg.
The chlorinating agent content of this second portion is generally greater than or equal to 1 g/kg, often greater than or equal to 5 g/kg and in particular greater than or equal to 10 g/kg. Said content is generally less than or equal to 50 g/kg, often less than or equal to 40 g/kg and in particular less than or equal to 30 g/kg.
The organic acid content of this second portion is generally greater than or equal to 1 g/kg, often greater than or equal to 5 g/kg and in particular greater than or equal to 10 g/kg. Said content is generally less than or equal to 150 g/kg, often less than or equal to 70 g/kg and in particular less than or equal to 30 g/kg.
The chlorohydrin ester content of this second portion is generally greater than or equal to 1 g/kg, often greater than or equal to 5 g/kg and in particular greater than or equal to 10 g/kg. Said content is generally less than or equal to 140 g/kg, often less than or equal to 70 g/kg and in particular less than or equal to 30 g/kg.
In a first aspect of this second variant, the basic agent is added solely to the first portion enriched with water.
In a second aspect of this second variant, the basic agent is added solely to the second portion enriched with chlorohydrin.
In a third aspect of this second variant, the basic agent is added to the first portion enriched with water and to the second portion enriched with chlorohydrin.
In a fourth aspect of this second variant, the basic agent is added to a mixture of the first portion enriched with water and the second portion enriched with chlorohydrin. The mixture may contain variable proportions of these two portions. The ratio by weight of the first portion enriched with water to the second portion enriched with chlorohydrin varies generally from 1/99 to 99/1, often from 89/11 to 11/89, frequently from 81/19 to 19/81, and in particular from 41/59 to 59/41.
An advantage of this second variant is that it is possible to know exactly the composition of the portions deployed in the dehydrochlorination reaction with the basic agent. This is because the composition of each of the portions is defined by the conditions under which the phase separation is operated, such as the temperature, the pressure and the composition of the fraction of the mixture obtained in step (a), including in particular the chlorinating agent content, the organic acid content and the chlorohydrin ester content. Knowledge of the composition of each of the portions deployed in the dehydrochlorination reaction in step (c) makes it possible to control this step more effectively.
In a third embodiment of the process for preparing an epoxide according to the invention, a fraction of the medium obtained in step (a) is withdrawn, this fraction having the same composition as the reaction medium obtained in step (a), this fraction is subjected to an evaporating, stripping or distillation treatment so as to give a part enriched with chlorohydrin, and the basic compound is added to this part.
The chlorohydrin content of this part is generally greater than or equal to 100 g/kg, often greater than or equal to 200 g/kg and in particular greater than or equal to 400 g/kg.
The chlorinating agent content of this part is generally greater than or equal to 0.01 g/kg, often greater than or equal to 0.05 g/kg and in particular greater than or equal to 0.1 g/kg. Said content is generally less than or equal to 110 g/kg, often less than or equal to 80 g/kg and in particular less than or equal to 65 g/kg.
The organic acid content of this part is generally greater than or equal to 0.01 g/kg, often greater than or equal to 0.1 g/kg and in particular greater than or equal to 1 g/kg. Said content is generally less than or equal to 270 g/kg, often less than or equal to 200 g/kg and in particular less than or equal to 130 g/kg.
Evaporation is intended to denote the separation of a substance by heating, under reduced pressure where appropriate.
Stripping is intended to denote the separation of a substance by vapour-mediated entrainment from a body which does not dissolve in said substance. In the process according to the invention, this body may be any desired compound which is inert relative to the chlorohydrin, such as, for example, water vapour, air, nitrogen or carbon dioxide. These same compounds may constitute the gaseous stream optionally present in the evaporation treatment.
Distillation is intended to denote the direct passage from the liquid state to the gaseous state and then condensation of the vapours obtained. By fractional distillation is meant a sequence of distillations conducted on the vapours successively condensed. The fractional distillation treatment is preferred.
The various embodiments may be combined with one another in any desired way.
By basic compound is meant basic organic compounds or basic inorganic compounds. Basic inorganic compounds are preferred. These basic inorganic compounds may be oxides, hydroxides and salts of metals, such as carbonates, hydrogen carbonates, phosphates or mixtures thereof, for example. Among the metals, preference is given to alkali metals and alkaline earth metals. Sodium, potassium and calcium and mixtures thereof are particularly preferred. The basic inorganic compounds may be present in the form of solids, liquids or aqueous or organic solutions or suspensions. Aqueous solutions or suspensions are preferred. The solutions and suspensions of NaOH, of Ca(OH)₂, purified alkaline brine and mixtures thereof are particularly preferred. By purified alkaline brine is meant the caustic soda, containing NaCl, of the kind produced in a diaphragm electrolysis process. The amount of basic compound in the solution or suspension is generally greater than or equal to 1% by weight and preferably greater than or equal to 4% by weight. This amount is commonly less than or equal to 60% by weight. An amount of approximately 50% by weight is particularly appropriate.
The basic compound may be used in superstoichiometric, substoichiometric or stoichiometric amounts with respect to the chlorohydrin. When the basic compound is used in substoichiometric amounts it is usual to use not more than 2 moles of chlorohydrin per mole of base. It is common to use not more than 1.5 moles of chlorohydrin per mole of base and preferably not more than 1.05 moles of chlorohydrin per mole of base. When the basic agent is used in superstoichiometric amounts use is made of not more than 2 moles of base per mole of chlorohydrin. In this case it is customary to use at least 1.05 moles of base per mole of chlorohydrin.
The process for preparing the epoxide according to the invention may be integrated into an overall scheme for preparing an epoxide as described in the application entitled “Process for preparing an epoxide from a chlorohydrin”, filed in the name of SOLVAY SA on the same day as the present application, and the content of which is incorporated here by reference.
Particular mention is made of a process for preparing an epoxide that comprises at least one step of purifying the epoxide formed, the epoxide being at least partly prepared by a process for dehydrochlorinating a chlorohydrin, the latter being at least partly prepared by a process for chlorinating a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof.
In the process according to the invention, the polyhydroxylated aliphatic hydrocarbon is preferably glycerol, the chlorohydrin is preferably dichloropropanol and the epoxide is preferably epichlorohydrin.
When the epoxide is epichlorohydrin the epoxide may be used for producing epoxy resins.

FIG. 1 shows one particular scheme of plant which can be used for implementing the separation process according to the invention.

A reactor (4) is supplied in continuous mode or in batch mode with the polyhydroxylated aliphatic hydrocarbon, the ester of the polyhydroxylated aliphatic hydrocarbon or the mixture thereof via line (1) and with catalyst via line (2); the chlorinating agent is supplied in continuous mode or in batch mode via line (3); a distillation column (6) is supplied via line (5) with vapours produced in reactor (4); a stream is withdrawn from column (6) via line (7) and is introduced into a condenser (8), the stream obtained from the condenser is introduced via line (9) into a phase separator (10), in which the aqueous phase and organic phase are separated. A fraction of the stream from line (7) may be withdrawn and conveyed into dehydrochlorinating reactor (31) via line (37). Dehydrochlorinating reactor (31) is supplied with basic agent via line (32). A stream containing the epoxide is withdrawn from reactor (31) via line (40). A fraction of the aqueous phase separated in phase separator (10) is optionally recycled via line (11) to the top of the column in order to maintain the reflux. Fresh water may be introduced into line (11) via line (12). The production of chlorohydrin is distributed between the organic phase withdrawn via line (14) and the aqueous phase withdrawn via line (13). A fraction of the stream from line (13) may be withdrawn and conveyed into a dehydrochlorinating reactor (31) via line (38). A fraction of the stream from line (14) may be withdrawn and conveyed into a dehydrochlorinating reactor (31) via line (39). Another part of the stream from line (14) may optionally be conveyed to the reflux of column (6) via line (30). The residue from column (6) may be recycled to reactor (4) via line (15). A fraction of heavy products is withdrawn from the reactor and is introduced via line (17) into an evaporator (18), in which a partial evaporation is conducted, for example, by heating or by gas purging with nitrogen or water vapour; the gaseous phase containing the majority of the chlorinating agent from stream (17) is recycled via line (19) to column (6) or via line (20) to reactor (4). Another fraction of heavy products is withdrawn from reactor (4) via line (16), a part of which is conveyed into a dehydrochlorinating reactor (31) via line (34). A fraction of the stream from line (17) may be withdrawn and conveyed into a dehydrochlorinating reactor (31) via line (35). A fraction of the stream from line (21) may be withdrawn and conveyed into a dehydrochlorinating column (31) via line (33). A distillation or stripping column (22) is supplied with the liquid phase from stripping apparatus (18) via line (21); the major part of the chlorohydrin is collected at the top of column (22) via line (23) and the residue, which contains esters of the polyhydroxylated aliphatic hydrocarbon and the chlorohydrin is introduced via line (24) into the filtration column (25), in which the liquid phase and solid phase are separated; the liquid phase is recycled via line (26) to reactor (4). A fraction of the stream from line (23) may be withdrawn and conveyed into a dehydrochlorinating column (31) via line (36). A solid may be withdrawn from the filtration unit (25) via line (27) in the form of a solid or of a solution. Solvents may be added to filtration unit (25) via lines (28) and (29) for the washing and/or the dissolving of the solid, and may be withdrawn via line (27).
The examples which follow are intended to illustrate the invention, though without subjecting it to any limitation.

EXAMPLE 1

In Accordance with the Invention

A mixture containing 80 g of dichloropropanol (0.62 mol), 9.7 g of hydrogen chloride (0.27 mol), 30 g of water and 1.3 g of acetic acid is preheated to 95° C. in a reactor surmounted by a distillation column. Over 30 minutes 132 g of a 280 g/kg aqueous solution of caustic soda are added thereto at a temperature of 95° C. and at a pressure of 0.59 bar. A mixture containing epichlorohydrin and water is removed continuously. After 20 minutes of additional reaction, after the end of the addition, 53.9 g of epichlorohydrin (0.58 mol) are recovered.

EXAMPLE 2

In Accordance with the Invention

A mixture containing 80 g of dichloropropanol (0.62 mol), 9.7 g of hydrogen chloride (0.27 mol), 900 g of water and 1.3 g of acetic acid is preheated to 95° C. in a reactor surmounted by a distillation column. Over 30 minutes 132 g of a 280 g/kg aqueous solution of caustic soda are added thereto at a temperature of 95° C. and at a pressure of 0.59 bar. A mixture containing epichlorohydrin and water is removed continuously. After 40 minutes of additional reaction, after the end of the addition, 52.2 g of epichlorohydrin (0.56 mol) are recovered.

Claims

1. A process for preparing an epoxide, wherein a reaction medium resulting from the reaction of a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof with a chlorinating agent, the reaction medium containing at least 10 g of chlorohydrin per kg of reaction medium, is subjected to a subsequent chemical reaction without intermediate treatment.

2. The process according to claim 1, wherein the subsequent chemical reaction is a dehydrochlorination reaction.

3. The process according to claim 2, wherein the dehydrochlorination reaction is carried out by adding a basic compound to the reaction medium.

4. A process for preparing an epoxide, comprising:

(a) a polyhydroxylated aliphatic hydrocarbon, an ester of a polyhydroxylated aliphatic hydrocarbon or a mixture thereof is reacted with a chlorinating agent and an organic acid so as to form the chlorohydrin and chlorohydrin esters in a reaction medium containing the polyhydroxylated aliphatic hydrocarbon, the ester of a polyhydroxylated aliphatic hydrocarbon, water, the chlorinating agent and the organic acid, the reaction medium containing at least 10 g of chlorohydrin per kg of reaction medium

(b) at least a fraction of the reaction medium obtained in step (a), this fraction having the same composition as the reaction medium obtained in step (a), is subjected to one or more treatments in steps subsequent to step (a), and

(c) a basic compound is added to at least one of the steps subsequent to step (a), in order to react at least partially with the chlorohydrin, the chlorohydrin esters, the chlorinating agent and the organic acid, so as to form the epoxide and salts.

5. The process according to claim 4, wherein, in the subsequent step, a fraction of the reaction medium obtained in step (a) is withdrawn, this fraction having the same composition as the reaction medium obtained in step (a), and the basic compound is added to it during the withdrawal.

6. The process according to claim 4, wherein, in the subsequent step, a fraction of the reaction medium obtained in step (a) is withdrawn, this fraction having the same composition as the reaction medium obtained in step (a), this fraction is subjected to a treatment of evaporating and/or stripping and/or distilling so as to give a part enriched with chlorohydrin, with chlorohydrin esters and with water, and the basic compound is added to the part enriched with chlorohydrin, with chlorohydrin esters and with water.

7. The process according to claim 6, wherein the part enriched with chlorohydrin, with chlorohydrin ester and with water is subjected to a decantation treatment so as to give a first position enriched with water and a second portion enriched with chlorohydrin and with chlorohydrin ester, and the basic agent is added to the first portion, to the second portion or to a mixture of the two portions.

8. The process according to claim 7, wherein the mass ratio between the first portion and the second portion in the mixture is greater than or equal to 1/99 and less than or equal to 99/1.

9. The process according to claim 4, wherein, in the subsequent step, a fraction of the reaction medium obtained in step (a) is withdrawn, this fraction having the same composition as the reaction medium obtained in step (a), this fraction is subjected to a distillation treatment so as to give a part enriched with chlorohydrin and with chlorohydrin ester, and the basic compound is added to this part.

10. The process according to claim 4, wherein the fraction of the reaction medium obtained in step (a) has a chlorohydrin content of greater than or equal to 100 g/kg and less than or equal to 700 g/kg, a chlorinating agent content of greater than 1 g/kg and less than or equal to 200 g/kg and a total organic acid content of greater than or equal to 1 g/kg and less than or equal to 500 g/kg.

11. The process according to claim 6, wherein the part enriched with chlorohydrin and with water has a chlorohydrin content of greater than or equal to 10 g/kg and less than or equal to 850 g/kg, a chlorinating agent content of greater than 0.01 g/kg and less than or equal to 110 g/kg of chlorinating agent and a total organic acid content of greater than or equal to 0.01 g/kg and less than or equal to 270 g/kg of organic acid.

12. The process according to claim 7, wherein the portion enriched with water has a chlorohydrin content of less than or equal to 500 g/kg of chlorohydrin, a chlorinating agent content of greater than 5 g/kg and less than or equal to 500 g/kg and a total organic acid content of greater than or equal to 0.01 g/kg and less than or equal to 5 mol/kg, and the portion enriched with chlorohydrin contains at least 400 g/kg of chlorohydrin, from 1 ppm by weight to 50 g/kg of chlorinating agent and from 0.0001 to 5 mol/kg of organic acid.

13. The process according to claim 9, wherein the part enriched with chlorohydrin has a chlorohydrin content of greater than or equal to 100 g/kg, a chlorinating agent content of greater than 0.01 g/kg and less than or equal to 110 g/kg and a total organic acid content of greater than or equal to 0.01 g/kg and less than or equal to 270 g/kg.

14. The process according to claim 1, wherein the polyhydroxylated aliphatic hydrocarbon, the ester of a polyhydroxylated aliphatic hydrocarbon or the mixture thereof is obtained starting from renewable materials.

15. The process according to claim 1, wherein the chlorinating agent contains hydrogen chloride.

16. The process according to claim 15, wherein the hydrogen chloride is a combination of gaseous hydrogen chloride and an aqueous solution of hydrogen chloride, or is an aqueous solution of hydrogen chloride.

17. The process according to claim 4, wherein the reaction of step (a) is catalyzed by the organic acid and the organic acid is not obtained during a process for preparing the polyhydroxylated aliphatic hydrocarbon.

18. The process according to claim 4, wherein the organic acid is acetic acid or adipic acid.

19. The process according to claim 3, wherein the basic compound is selected from aqueous solutions or suspensions of NaOH, of Ca(OH)₂, purified alkaline brine and mixtures thereof and wherein the molar ratio of the basic compound and the chlorohydrin is greater than or equal to 0.5 and less than or equal to 2.

20. The process according to claim 1, wherein the polyhydroxylated aliphatic hydrocarbon is selected from ethylene glycol, propylene glycol, chloropropanediol, glycerol and mixtures of at least two thereof.

21. The process according to claim 1, wherein the chlorohydrin is selected from chloroethanol, chloropropanol, chloropropanediol, dichloropropanol and mixtures of at least two thereof.

22. The process according to claim 1, wherein the epoxide is selected from ethylene oxide, propylene oxide, glycidol, epichlorohydrin and mixtures of at least two thereof.

23. The process according to claim 1, wherein the polyhydroxylated aliphatic hydrocarbon is glycerol, the chlorohydrin is dichloropropanol and the epoxide is epichlorohydrin.

24. The process according to claim 23, wherein the epichlorohydrin is used for producing epoxy resins.

25. A process for preparing epichlorohydrin, wherein a mixture containing dichloropropanol, hydrogen chloride and an organic acid is reacted with an aqueous solution of a basic agent.