PROCESS FOR THE CO-PRODUCTION OF CYCLIC CARBONATES AND FATTY NITRILES AND/OR AMINES
The invention is directed toward a conjugate process for synthesizing, on the one hand, fatty nitriles and/or amines, and, on the other hand, polyol carbonates, from natural oils.
The current evolution in the environmental field is tending in the energy and chemistry sectors toward favoring the exploitation of natural starting materials derived from a renewable source. These environmental constraints also impose the constraint of avoiding the transportation and storage of hazardous starting materials.
An example of an industrial process using a fatty acid as starting material is that for the manufacture of fatty nitriles and/or amines from a fatty acid that may be derived from an animal or plant triglyceride. This process is described in Kirk-Othmer's encyclopedia, Vol. 2, 4th edition, page 411. The fatty amine is obtained in several steps. The first consists of a methanolysis or a hydrolysis of a plant oil or an animal fat, producing, respectively, the methyl ester of a fatty acid or a fatty acid. The methyl ester of the fatty acid may then be hydrolyzed to form the fatty acid. Next, the fatty acid is converted into the nitrile by reaction with ammonia, and finally into the amine by hydrogenation of the nitrile thus obtained.
The preparation of fatty amines from fatty acids via a nitrile dates from
the 1940s. The reaction scheme for the synthesis of the nitriles may be
summarized in the following manner:
(Formula Removed)
Two types of process exist based on this reaction scheme: a liquid-phase
batch process that is performed by the company CECA, and a vapor-phase
continuous process.
In the batch process, the fatty acid or a mixture of fatty acids is charged
with a catalyst, which is generally a metal oxide and usually zinc oxide. The

reaction medium is brought to about 150°C with stirring, and the introduction of ammonia gas is then commenced. In a first stage, an ammonium salt or ammonium soap is formed. The temperature of the reaction medium is then raised to about 250-300°C with continued introduction of ammonia. The ammonium salts becomes converted into the amide with release of a first molecule of water. Next, in a second stage and with the aid of the catalyst, the amide becomes converted into the nitrile with formation of a second molecule of water. This water formed is removed continuously from the reactor, entraining the unreacted ammonia and a small amount of the lightest fatty chains. Passage through a dephlegmator retrogrades the fatty compounds toward the reaction medium, whereas the ammoniacal liquors are conveyed to a system for recovering the ammonia, which may be recycled. The reaction is complete when there are no more acid functions and when the amide content is in accordance with the specifications.
In the continuous process, the reaction takes place in the vapor phase at high temperature levels and generally on a fixed bed of doped or undoped alumina.
The advantage of the batch process is that it leads to more or less pure nitriles since they are generally distilled, whereas this is not the case in the continuous process. On the other hand, the continuous process is more advantageous when it concerns unsaturated or polyunsaturated fatty-chain nitriles, which are thermally more sensitive than saturated fatty-chain compounds. Specifically, in this process, the residence time is short and the iodine number, which reflects the number of unsaturations, is better maintained.
The step for synthesizing the fatty amines consists of a standard hydrogenation of fatty nitriles. Many catalysts are available, but Raney nickel or Raney cobalt is preferentially used. In order to promote the formation of the primary amine, the process is performed with a partial pressure of ammonia, whereas, when it is desired to obtain a secondary amine, no partial pressure of ammonia is used, and the ammonia formed during the reaction is removed, if possible.

Many patent applications describe the conditions for performing the synthesis of fatty acid nitriles or fatty amines from triglycerides or methyl esters. One example that may be mentioned is document JP 2000-7637, which describes the synthesis of nitriles from methyl esters of linear or branched, saturated or unsaturated fatty acids containing from 6 to 22 carbon atoms, and ammonia, at a temperature ranging from 180 to 350°C in the presence of a catalyst of niobium oxide type. Patent US 6 005 134 describes a process for synthesizing aliphatic nitriles from C6-C22 carboxylic acids, alkyl esters of C6-C22 carboxylic acids or from triglycerides, the reaction with ammonia being performed in the presence of a catalyst comprising at least titanium. The results obtained indicate, however, lower yields starting with esters or triglycerides when compared with the acids. In patent JP 10-195 035, an iron-doped zirconium oxide catalyst leads to excellent yields of nitrile, but the authors mention the presence of light amines associated with the formation of methanol in the case of the methyl esters. Patent US 4 801 730 describes a process for simultaneously preparing fatty acid nitriles and glycerol from triglycerides. The reaction is performed in two steps, with production in a first stage of glycerol, water, fatty acids, fatty acid amides and nitriles by reaction with ammonia, and then by reacting again the mixture of fatty acids, fatty amides and fatty nitriles with ammonia to convert the fatty acids and amides into nitriles.
The process for synthesizing fatty nitriles and/or amines, performed industrially using fatty acids, has been satisfactory overall for several decades. However, it presents a certain number of drawbacks. The main drawback is that its implementation is in practice subject to access to a specific starting material, in particular ammonia, which requires costly precautions for storage and use.
When a triglyceride is used as source of fatty acid for the process for synthesizing fatty nitriles and/or amines, the process produces glycerol, during its first step of methanolysis of the triglyceride, but also methanol during the consecutive hydrolysis step. This methanol is then purified and concentrated in order to be recycled to perform the initial methanolysis step.
There are several routes for synthesizing glyceryl carbonate. Certain processes use phosgene, others use an oxidation of glycerol in the presence of

CO (JP 6 157 509 and US 5 359 094), yet others use a transesterification with another carbonate, and finally other processes use a transesterification of glycerol with urea.
Glyceryl carbonate has been produced for many years by transesterification with ethylene carbonate under homogeneous catalysis (US 2 915 529, FR 2 733 232, US 5 091 543). Other carbonate synthesis processes use heterogeneous catalysts (US 4 691 041).
Patent application EP 955 298 describes a process for transesterifying glycerol with urea, using a catalyst bearing Lewis acid sites associated with one or more anionic counterions of heteroatoms. The experiments showed that the glycerol introduced could be in the form of technical-grade glycerol.
Patent US 6 495 703 also describes a process for producing glyceryl carbonate by transesterifying urea. The reaction is preferably performed in the presence of a dehydrating agent.
It should be noted that carbonatation reactions using urea have already been described for other polyols (EP 443 758 and EP 581 131).
In the process for synthesizing fatty nitriles and/or amines, it is necessary to import and store large amounts of ammonia, which, besides the transportation problems, represents a major risk in the event of a leak, not only for the personnel but also for anyone in the vicinity. This storage consequently imposes major constraints on the site exploiting this type of process.
The problem to be solved is that of limiting these environmental risks while at the same time maintaining the efficiency of the process or, better still, improving it.
The invention is thus directed toward a conjugate process for producing fatty nitriles and/or amines and polyol carbonates from a natural saturated or unsaturated triglyceride, in which the same natural triglyceride will serve as starting material for the synthesis of fatty nitriles and/or amines, on the one hand, and of polyol carbonates, on the other hand. The synthesis of the polyol carbonates is performed via the action of urea on the polyol, and the ammonia thus produced may be used as reagent, on the one hand for the step of ammoniation of the fatty acids derived from the triglyceride during the synthesis

of the nitrile, and on the other hand for the step of hydrogenation of the nitrile during the synthesis of the primary amine.
The invention is directed toward a conjugate process for producing fatty nitriles and/or amines and polyol carbonates from a natural oil, including the following zones:
I) zone for methanolysis or hydrolysis of a natural oil containing a triglyceride of at least one fatty acid, producing, on the one hand, the methyl ester of the fatty acid or the fatty acid corresponding to the general formula R-COOR1, in which R is a saturated or unsaturated alkyl radical containing from 7 to 21 carbon atoms and preferably from 11 to 17 carbon atoms, and R1 is either CH3 in the case of methanolysis, or H in the case of hydrolysis, and, on the other hand, glycerol,
II) zone for synthesis of a fatty amine, including the following steps a) optional conversion firstly of the methyl ester of the fatty acid into a fatty acid via hydrolysis of the ester derived from step I), followed in b) by an ammoniation reaction with ammonia of the acid or of the fatty acid methyl ester obtained from zone I or of the acid obtained from step a), to form a nitrile, and then in c) a reduction with hydrogen of the compound resulting from step llb, optionally in the presence of ammonia, to obtain the corresponding amine,
III) zone for synthesis of a polyol carbonate by reaction of urea, either directly on glycerol, or on propylene glycol or ethylene glycol obtained following a reduction by hydrogenation of glycerol, the reaction of the polyol with the urea producing ammonia,
IV) zone for recovery of the ammonia obtained from zone III, and also
that obtained from zone llb in which the reaction is performed with an excess of
ammonia, and optionally that obtained from zone llc, to serve as feed for the
ammoniation of step llb and optionally the hydrogenation of step llc of zone II.
The process of the invention is described with reference to the attached simplified scheme in Figure 1.
Zone I is fed via line 1 with natural oil containing a triglyceride, on the one hand, and with methanol or water via line 2, on the other hand. Once the

methanolysis or hydrolysis reaction of the triglyceride has been performed in
zone la according to the following reaction:
(Formula Removed)
R, R' and R" being saturated or unsaturated alkyl radicals containing from 7 to
21 carbon atoms and preferably from 11 to 17 carbon atoms, R, R' and R"
being identical or different, and R1 being either CH3 or H.
Separation is then performed, generally by decantation in zone lb, on the one hand of the methyl ester of the fatty acid or the fatty acid of the triglyceride, which is then conveyed via line 3 to zone II, and on the other hand of the glycerol, which is conveyed via line 11 to zone III. The residual compounds are extracted from zone I via line 19.
The methyl ester of the fatty acid formed in zone la is then transferred into zone Ila where it is subjected to a hydrolysis in order to obtain the corresponding fatty acid. Water is introduced via line 5 and the methanol is extracted via line 6. This methanol, optionally purified, may be recycled into zone I for the transesterification reaction.
The fatty acid obtained from zone lla or obtained directly from zone lb, or
the methyl ester of the fatty acid obtained from zone lb is introduced into zone
lib where it is subjected to an ammoniation reaction with excess ammonia to
obtain the fatty nitrile according to the following reaction process:
(Formula Removed)
The ammonia is introduced via line 7. The excess ammonia and the water produced from the fatty acid are extracted via line 8 and conveyed to section IV for purification. The excess ammonia and the water and methanol produced from the methyl ester of the fatty acid are extracted via line 14 and/or 8, the methanol produced possibly being recycled, after purification, into zone I for the transesterification reaction.
The nitrile obtained from zone llb is introduced into zone llc where it is subjected to a reduction with hydrogen, optionally in the presence of ammonia,


according to the following reaction process:
(Formula Removed)
The ammonia is introduced into zone llc via line 17 and the hydrogen via line 4. The fatty amine is extracted from zone II via line 9, and the excess ammonia is conveyed to section IV for purification. In general, the ammonia for ail these operations is in gaseous form, but may be in liquefied, aqueous or anhydrous form depending on the streams.
The glycerol obtained from zone I is conveyed via line 11 to zone III in which urea is injected via line 12 to form glyceryl carbonate according to the following reaction process:
(Formula Removed)
The glyceryl carbonate synthesized is extracted from zone III via line 13 and the ammonia formed is conveyed to zone IV via line 15.
When it is desired to synthesize a cyclic carbonate of 1,2- or 1,3-propylene glycol, zone III is divided into two zones Illa and lllb; in zone Ilia, a partial reduction of glycerol is performed by injecting hydrogen via line 18 and the propylene glycol(s) is (are) transferred after having been separated from the water produced by the hydrogenation reaction, in zone lllb in which takes place the reaction with urea to form the 5- or 6-atom cyclic propylene glycol carbonates according to the structure of the reacted propylene glycol.
If it is desired to obtain ethylene glycol carbonates, it is possible to perform the process by modifying the operating conditions in zone Illa to a hydrogenolysis of glycerol under more severe conditions producing ethylene glycol, which is converted via the action of urea into a 5-atom-ring ethylene carbonate. In practice, the glycerol hydrogenation operations usually
mixture of propylene glycol and ethylene glycol.
Zone IV comprises, besides the feed lines 15, 8 and 10, a supply line 16 that makes it possible especially to provide the ammonia required for starting up the unit and for regulating it in the case of variation of the production of ammonia in zone III.
The process is particularly suited to the synthesis of fatty nitriles and/or amines. The various reactions will be as follows:
Zone I: plant oil + SRiOH
The same reactions apply for R' and R".
(Formula Removed)
The same process may also be used for the production of nitriles/amines directly from ester or triglyceride. To do this, steps lla and/or I will optionally be omitted.
The conditions for performing the various steps of zones I, II, III and IV are known to those skilled in the art.
It may, however, be pointed out that:
- the methanolysis of zone I is generally performed, for example, at a temperature between 60 and 100°C in the presence of a catalyst such as sodium methoxide and with an excess of methanol. It is also possible to use heterogeneous catalysis at higher temperature, or even acid catalysis.
- The hydrolysis of zone I is generally performed in the presence of an acid catalyst.
- The hydrolysis reaction of step a) of zone II is performed, for example, at room temperature or even at a slightly higher temperature.

- The ammoniation of step b) in zone II leading to the nitrile is performed at a temperature ranging from 150 to 400°C and preferably at a temperature in the region of 300°C.
- the hydrogenation of step c) in zone II leading to an amine is performed at a temperature ranging from 80 to 170°C, preferably in the presence of ammonia to form the primary amine.
- The conversion of glycerol into glyceryl carbonate performed in zone III has, as has been indicated previously, been known for many years. To perform the process, the solution adopted is transesterification of glycerol with urea. This reaction is performed in the presence of catalysts that are known per se, for example those described in patents US 6 495 703, zinc oxide, or EP 0 955 298, organometallic or zinc metal sulfates.
In one variant, the process makes it possible to obtain carbonates of polyols other than glycerol, namely diols comprising 3 carbon atoms such as 1,2-propanediol (or 1,2-propylene glycol), 1,3-propanediol and ethylene glycol (or ethanediol), and especially 1,2-propylene glycol, which are obtained via hydrogenation of the glycerol obtained from zone I. This hydrogenation is performed under conditions that are well known to those skilled in the art.
Several patent applications and articles describe the conditions for performing the transformation via hydrogenation of glycerol into propylene glycol, propanediol and ethylene glycol. Mention may be made of patents US 5 276 181, US 5 214 219, US 5 616 817 and US 4 642 394 and the following articles: Daniel G. Lahr et al. J. Catal. 232 (2005), 386-394, Daniel G. Lahr et al. Ind. Eng. Chem. Res. (2003) 42, (22), 5467-5472. Moreover, routes also using fermentation processes have been described for the conversion of glycerol to propanediol and propylene glycol, for example in the following articles: D.C. Cameron et al. Biotechnology 4 (1986), 651, D.C. Cameron et al. Biotechnol. Prog. 14(1998), 116.
Patent US 4 642 394 describes a process for producing a mixture of 1,2-and 1,3-propanediols from glycerol via the action of a synthesis gas (H2 + CO) in an organic solvent medium in the presence of a soluble catalyst based on tungsten and a Group VIM metal.

Patent US 5 214 219 describes a process for producing a mixture of 1,2-propanediol and ethanediol from glycerol via hydrogenation of the glycerol in the presence of a zinc-copper heterogeneous catalyst in an aqueous or alcoholic solvent medium.
Patent US 5 616 817 describes a process for producing 1,2-propanediol from glycerol in the presence of a heterogeneous catalyst based on cobalt, copper, manganese and molybdenum.
The transesterification of 1,2-propanediol with urea for the synthesis of propylene carbonate is described by Xinqiang Zhao et al. in an article entitled "Synthesis of Propylene Carbonate from Urea and 1,2-Propylene Glycol over a Zinc Acetate Catalyst" Ind. Eng. Chem. Res., 43 (15), 4038-4042, 2004. According to the same authors, in an article published in the Journal of Chemical Technology & Biotechnology in 2006, the same reaction may be performed with a zinc-iron double oxide catalyst.
The transesterification of ethanediol with urea has been described by Chiyoda and Mitsubishi Gas Chemical in a publication by Chiyoda on the synthesis of ethylene carbonate. (ACS 212th National Meeting, August 1996, Div. Fuel Chem. Preprint, Vol. 41, No. 3, pp. 868-872). Experimental data cited in a Mitsubishi Gas Chemical patent (US 5 489 702) show that at 145°C and under 100 mmHg, with a contact time of 2 hours, and using a zinc oxide catalyst, a total conversion of the urea is obtained for a selectivity toward ethylene carbonate of greater than 97% relative to the urea and relative to the ethylene glycol.

CLAIMS
1) A conjugate process for producing fatty nitriles and/or amines and polyol carbonates from a natural oil, including the following zones:
I) zone for methanolysis or hydrolysis of a natural oil containing a triglyceride of at least one fatty acid introduced via line 1, with methanol or water introduced via line 2, producing, on the one hand, the methyl ester of the fatty acid or the fatty acid corresponding to the general formula R-COOR^ in which R is a saturated or unsaturated alkyl radical containing from 7 to 21 carbon atoms, R^ is either CH3 in the case of methanolysis, or H in the case of hydrolysis, and, on the other hand, glycerol, which are, respectively, conveyed, after separation in zone lb, to the zones II via line 3 and zone III via line 11,
II) zone for synthesis of a fatty amine, including the following steps a) optional conversion firstly of the methyl ester of the fatty acid introduced via line 3 into a fatty acid via hydrolysis of the ester derived from step I), the water being introduced via line 5 and the methanol extracted via line 6, followed in b) by an ammoniation reaction with excess ammonia, introduced via line 7, of the acid or of the fatty acid methyl ester obtained from zone I introduced via line 3 or of the acid obtained from step a), to form a nitrile, the excess ammonia and the water produced being extracted via line 8 or the excess ammonia and the water and the methanol produced being extracted via line 14 and/or 8, and then in c) a reduction with the hydrogen introduced via line 4 of the compound resulting from step Mb, optionally in the presence of ammonia introduced via line 17, to obtain the corresponding amine, extracted via line 9, with optional recycling of the ammonia into zone IV via line 10,
III) zone for synthesis of a polyol carbonate by reaction of urea, either directly on the glycerol conveyed via line 11, or on propylene glycol or ethylene glycol obtained following a reduction by hydrogenation of glycerol, the reaction of the polyol with the urea producing ammonia, the polyol carbonate being extracted via line 13 and the ammonia formed conveyed to zone IV via line 15,
IV) zone for recovery of the ammonia obtained from zone III via line 15, and also that obtained via line 8 obtained from zone lib in which the reaction is

performed with an excess of ammonia, and optionally that via line 10 obtained from zone llc, to serve as feed via line 7 for the ammoniation of step lib and optionally via line 17 for the hydrogenation of step llc of zone II.
2) The process as claimed in claim 1, characterized in that the reaction in zone I is a methanolysis to obtain a compound of formula R-COOCH3 in which R is a saturated or unsaturated alkyl radical containing from 7 to 21 carbon atoms.
3) The process as claimed in claim 1, characterized in that the reaction in zone I is a hydrolysis to obtain a compound of formula
R-COOH in which R is a saturated or unsaturated alkyl radical containing from 7 to 21 carbon atoms.

4) The process as claimed in one of claims 1 to 3, characterized in that the glycerol obtained from zone I and conveyed to zone HI is converted into glyceryl carbonate via the action of urea.
5) The process as claimed in one of claims 1 to 3, characterized in that the glycerol obtained from zone I and conveyed to zone III is reduced in a zone llla via the action of hydrogen to at least one diol, propanediol and/or ethanediol, the latter then being converted into propanediol and/or ethanediol carbonates via the action of urea.