Ep 3041814 B1

(19) TZZ¥Z___T (11) EP 3 041 814 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C07C 29/62 (2006.01) 08.11.2017 Bulletin 2017/45 (86) International application number: (21) Application number: 14790356.1 PCT/IT2014/000227 (22) Date of filing: 01.09.2014 (87) International publication number: WO 2015/033365 (12.03.2015 Gazette 2015/10) (54) PROCESS FOR THE PRODUCTION OF DICHLOROHYDRINS VERFAHREN ZUR HERSTELLUNG VON DICHLORHYDRINEN PROCÉDÉ DE PRODUCTION DE DICHLORHYDRINES (84) Designated Contracting States: (72) Inventors: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB • SANTACESARIA, Elio GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO I-20139 Milano (IT) PL PT RO RS SE SI SK SM TR • TESSER, Riccardo I-81100 Caserta (IT) (30) Priority: 03.09.2013 IT RM20130488 • VITIELLO, Rosa I-84018 Scafati (SA) (IT) (43) Date of publication of application: • DI SERIO, Martino 13.07.2016 Bulletin 2016/28 I-74013 Cava dei Tirreni (SA) (IT) (73) Proprietors: (74) Representative: Sarpi, Maurizio et al • Eurochem Engineering S.R.L. Studio Ferrario S.r.l. 20139 Milano (IT) Via Collina, 36 • Conser S.P.A. 00187 Roma (IT) 00144 Rome (IT) (56) References cited: WO-A1-2006/020234 Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 3 041 814 B1 Printed by Jouve, 75001 PARIS (FR) EP 3 041 814 B1 Description Technical field of the invention 5 [0001] This invention is related to the chlorohydrins production process starting from glycerol as feedstock and hydrochloric acid in the presence of an opportune catalyst. In particular, the invention deals with a new process for producing dichlorohydrins with a high selectivity in the production of α,γ-dichlorohydrin from glycerol and hydrochloric acid in the presence of a new class of catalysts constituted by acyl chlorides. 10 State of art [0002] Glycerol can be used as raw material for the production of di-chlorohydrins, in particularα ,γ-dichlorohydrin, that is an intermediate for producing epichlorohydrin, useful in the production of epoxy resins [1-7]. The overall reaction scheme in the production of α,γ-dichlorohydrin starting from glycerol and hydrochloric acid is the 15 following one: 20 25 [0003] Actually, the reaction proceeds through two consecutive steps giving place in the first step to monochlorohydrins: mainly α-monochloroydrin with small amounts of β-monochloroydrin. Then a second step of chlorination occurs giving place to the desired productα ,γ-dichlorohydrin together with small amounts ofα ,β-dichlorohydrin. A more detailed 30 reaction scheme is reported below: 35 40 45 50 55 2 EP 3 041 814 B1 5 10 The traditional, very old processes, based on the use of glycerol as raw material proposed the use of aqueous hydrochloric acid and acetic acid as catalyst. The reaction was performed in the temperature range of 80-100°C [8-11]. Some patents describe processes in which an organic solvent, inert to the reaction and immiscibile with water but a good solvent for α,γ-dichlorohydrin, was added. In this case. the boiling temperature of the solvent was the reaction temperature obviously changing with the chosen solvent but never higher than 110°C [12]. 15 Some other patents describe the reaction followed by complicated operations of neutralization, extraction and distillation for recovering α,γ-dichlorohydrin [13,14]. All these processes have some important drawbacks, as: - the loss of catalyst during the reaction considering the low boiling point of acetic acid (117°C), 20 - the slowering of the reaction caused by the accumulation of water in the reaction mixture occurring either when aqueous hydrochloric acid is added as reagent or when water is formed as a consequence of the reaction. - the difficulty of separating the desired product α,γ-dichlorohydrin from the reaction mixture at the end of the reaction. These drawbacks together with the high cost of glycerol hindered in the past a further development of these processes. 25 At the present time, the most practiced process for producing di-chlorohydrins start use propene as raw material and gives place to a mixture of di-chlorohydrins containing 70 % ofα ,β- dichlorohydrin and 30 % α,γ-dichlorohydrin. Also this process has some drawbacks. As a matter of fact, the high content α,β-dichlorohydrin is a problem, because, the dehydrochlorination of α,β- dichlorohydrin to epichlorohydrin is much slower than the one of α,γ-dichlorohydrin. This has a negative impact on both the size of the industrial reactors and on the yields [5,6]. 30 Therefore, the reaction using glycerol instead of propene as raw material would be potentially more convenient provided that glycerol is available at low cost. At this purpose, it is useful to remember that the production of biodiesel gives place to 10% b.w. of glycerol as by-product. As a consequence, the glycerol availability increases and the cost decreases. Moreover, considering that the cost of glycerol is strongly affected by the purification it must be pointed out that hydro- chlorination can be made also by using unrefined glycerol. 35 [0004] Some patents have recently been published claiming the production of chlorohydrins from glycerol using an- hydrous gaseous hydrochloric acid. All these patents suggest the use of carboxylic acids as catalysts promoting the reaction and the difference between the mentioned patents is related to the type of carboxylic acid used and/or for the adopted operative conditions. One of the advantages of producing chlorohydrins from glycerol and gaseous hydrochloric acid in the presence of carboxylic acids as catalysts with respect to the route via propene is the high selectivity to α,γ- 40 dichlorohydrin that is normally obtained. This means the possibility to reduce the volume of the dehydrochlorination reactors for obtaining epichlorohydrin and for the same volume an increase of productivity. One of the aspects much considered in the different published patents is the adoption of carboxylic acids, as catalyst, less volatile than acetic acid having a boiling point (117°C) near to the reaction temperature. In the patent proposed by Solvay [15], for example, the use of adipic acid is proposed. In the patent published by Eurochem Engineering [16] the 45 use of the following carboxylic acids is proposed: propionic acid, malonic acid, levulinic acid, citric acid, succinic acid and is suggested the possibilità of recovering by stripping α,γ-dichlorohydrin. In the patent published by DOW Global Technologies [17] an exhaustive very long list of carboxylic acids as possible catalysts is reported but in particular the advantage of operating under pressure is stressed being the reaction rate and yields strongly affected by the partial pressure of HCl [18,19]. In the patent by CONSER SpA [20] it has been suggested the opportunità to operate by using 50 two different catalysts in sequence, adding malic acid at low pressure (1-2 bars) initially, adding then succinic acid at higher pressure (8-10 bars). The performances of the carboxylic acid as catalysts have been intensively studied [18,21,22] and a rough correlation has been found between the pKa of the acid (must be comprised in the range 4-5) and the catalytic activity. For example, the sequence acetic acid, mono-, di- and tri-chloroacetic shows a decreasing activity, because, the acid strength of the 55 mentioned acids increases with the content of chlorine [22]. Some carboxylic acids resulted selective in producing monochlorohydrins [21-23]. A reaction mechanism has been suggested to explain the observed kinetic behaviour [23]. In the frame of the studies performed with the objective to find the optimal catlayst for promoting the glycerol hydrochlo- rination, surprisingly we have discovered a new class of very active and selective catalysts never proposed in the past 3 EP 3 041 814 B1 constituted by acyl chlorides. Summary of the invention 5 [0005] The object of this invention is the process for the production of chlorohydrins starting from glycerol and gaseous hydrochloric acid using acyl chloride as catalysts for promoting the reaction. The catalysts of this invention have the following general formula RCOC1 and the following structure: 10 15 20 Where R is an alkyl chain with from 2 to 10 carbon atoms having a structure linear, branched or cyclic, eventually containing one or more R’ groups, if more equal or different. R’ groups are chosen between: linear alifatic groups, 25 branched or cyclic with C1-C10. carbon atoms or aromatic (C1-C10), another or more than one acylic group. By comparing the behavior of the acyl chlorides with the corresponding carboxylic acids it is possible to observe, in the same operative conditions, much greater reaction rates and final yields in α,γ-dichlorohydrin. By using acyl chloride the reaction time is strongly reduced as it will be seen in the examples reported later. This kinetic advantage becomes more and more evident by increasing the partial pressure of HCl. At last, it has been observed that inorganic salts, in particular 30 inorganic chloride like sodium or potassium chloride have a further positive effect on the activity of the acyl chloride. This is very important for industrial purpose, because, allows the use of the crude glycerol coming from the biodiesel plants without any expensive purification step. It is known, in fact, that in biodiesel production NaOH or KOH are used as catalysts and at the end of the reaction the catalyst remains dissolved in the polar phase containing a mixture of methanol and glycerol.

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