||||||||||||||||| USOO5260456A United States Patent (19) 11 Patent Number: 5,260,456 Alas et al. (45) Date of Patent: Nov. 9, 1993 (54) PROCESS FOR PRODUCING ITACONIC ANHYDRIDE FOREIGN PATENT DOCUMENTS (75) Inventors: Michel Alas, Melle; Michel 801722 9/1958 United Kingdom . Gubelmann, Lyons; Jean-Michel 854999 11/1960 United Kingdom . Popa, Drancy, all of France 81/O1844 7/1981 World int. Prop. O. ............ 502/81 73) Assignee: Rhone-Poulenc Chimie, Courbevoie, OTHER PUBLICATIONS France McCabe et al., Clay-and Zeolite-catalysed Cyclic An hydride Formation, 356.J. Chem. Research (S), 1985 pp. (21) Appl. No.: 870,773 356-357. 22) Filed: Apr. 21, 1992 Franz et al., Katalysatoren auf der Basis saureaktivierter Bentonite, Erdol und Kohle, 12 Jahrg./Mai 1959, Nr. 5, Related U.S. Application Data pp. 335-339. Gunther, Chem. Abs. 55 25 234b Notification from (63. Continuation of Ser. No. 524,880, May 18, 1990, aban European Patent Office, Feb. 4, 1991 with attached doned, which is a continuation-in-part of Ser. No. Rapport De Recherche Europeenne, EP 8840 2809. 272,793, Nov. 18, 1988, abandoned. Cram and Hammond, Organic Chemistry, 30) Foreign Application Priority Data McGraw-Hill, N.Y., pp. 310-311 (1959). McCabe et al., J. Chem. Research (S), pp. 356-357 Nov. 20, 1987 (FR) France ................................ 87 6065 (1985). 51 Int. Cl. ............................................ CO7D 307/60 Primary Examiner-Bernard Dentz 52 U.S. Cl. .................................... 549/233; 549/231; Attorney, Agent, or Firm-Finnegan, Henderson, 549/239; 549/245; 549/247; 549/262; 502/81; Farabow, Garrett & Dunner 502/82; 502/83 (58) Field of Search ............... 549/231, 233, 239, 245, 57 ABSTRACT 549/247, 262; 502/81, 82, 83 A process for producing anhydrides by passing a solu 56 References Cited tion of the acid, preferably an organic polyacid, which is to undergo anhydridation over an acidified clay and a U.S. PATENT DOCUMENTS process for producing the catalysts therefor. 2,981.697 4/1961 Mickelson et al. ................... 502/82 3,704,329 11/1972 Rindtorff et al. ................... 568/896 14 Claims, No Drawings 5,260,456 1. 2 advantages of the invention may be realized and ob PROCESS FOR PRODUCING ITACONIC tained by means of the instrumentalities and combina ANHYDRIDE tions particularly pointed out in the appended claims. To achieve the foregoing objects, and in accordance This application is a continuation of application Ser. 5 with the purposes of the invention as embodied and No. 07/524.880 filed May 18, 1990, now abandoned broadly described herein, there is provided a process which is a continuation-in-part of application Ser. No. for producing acid anhydrides which comprises bring 07/272,793 filed Nov. 18, 1988, now abandoned. ing into contact, for a period of time sufficient to pro The present invention relates to a process for produc duce the acid anhydride, an acid, preferably an organic ing acid anhydrides and catalysts therefor. More specifi 10 polyacid and more preferably, a polycarboxylic acid, cally, it relates to a process for producing internal anhy which is to undergo anhydridation and a clay which has drides, such as itaconic acid anhydride, from organic undergone one or more treatments by one or more polyacids. It also relates to a new catalyst for such compounds, preferably acids or ammonium salts, capa processes. It is an aim of the present invention to pro ble of providing an H-- ion to the clay. The invention duce itaconic anhydride from itaconic acid with a low 15 also relates to a process for producing an acid anhydride production of citraconic acid. which comprises bringing into contact, for a period of The preparation of itaconic anhydride by exchange time sufficient to produce the acid anhydride, an acid between itaconic acid and acetic anhydride using the which is to undergo anhydridation and a clay contain conventional processes of transanhydridation, is known ing H-- ions in an amount sufficient to effect anhydrida from the prior art. This process has the disadvantage of 20 tion. using a raw material which is expensive, namely acetic Clays which can be used in the process of the present anhydride, with the formation of a by-product which invention are preferably selected from natural clays must be eliminated, i.e., acetic acid. The reaction is having a structure known as "TOT" or tetrahedron further limited as to the temperature which can be used octahedron-tetrahedron. to avoid initiating a polymerization reaction. A temper 25 These clays are divided into three classes: ature below 75 C. is essential. The yields obtained by smectites; this process do not exceed 90% of itaconic anhydride. vermiculites; and Moreover, the industry has for a long time been seeking micas. to carry out anhydridation of itaconic acid directly "TOT" clays occur in the form of simple lamellae from the acid without the necessity of using another 30 comprising two layers of oxygen atoms in tetrahedral anhydride, such as acetic anhydride. positions surrounding silicon atoms, separated by one It has also been disclosed in the article which ap layer of oxygen atoms in octahedral positions surround peared in J. Chem. Research (S) 1985, 356-357, that ing the metal M of the type (MO4OH2) where M is a di itaconic anhydride can be produced by passing itaconic or trivalent cation. acid over a proprietary clay of the type exemplified by 35 TONSIL 13 from Sud-Chemie (Munich) treated with When the tetrahedra are occupied by Sil’species, the an aluminum salt. This technique employs clays which electrical neutrality of the lamella is maintained in two have been exchanged with an aluminum salt. On the one ways, depending on the charge of the cation occupying hand, this has the disadvantage that the natural clay . the octahedra: requires a quite elaborate treatment which increases the 40 if it is divalent (Mg,Fe+2,...), all the octahedral cost of producing the anhydride. A noteworthy, but not cavities are occupied. The lamella is then called trioc necessarily advantageous, feature of this technique is tahedral. that the double bond of the itaconic molecule is stable if it is trivalent (Alt 3, Fe+3, . ), two octhadral cavities out of three are occupied and the lamella is under the reaction conditions, contrary to the usual called dioctahedral. catalytic rearrangement of itaconic acid into citraconic 45 acid. Among the disadvantages of the catalyst disclosed However, numerous substitutions are possible, in in the above-identified paper are the following: both the tetrahedral layer and the octahedral layer. the catalyst reverts to a less active form within a These can produce an excess of negative charge in the relatively short time: lamella. Neutrality of the crystal is then achieved by it is costly to prepare and produces many dirty efflu 50 compensating cations being inserted between the lamel ents; lae. the catalyst needs water to be active, thus it is not Among clays of the "TOT" type defined above, useful in reactions which are conducted in such a way smectites are preferably used. as to remove water; Smectites are classified according to the nature of the the catalyst is not versatile and is not able to easily 55 metal M (aluminum, magnesium iron, lithium) and the cyclize common di-acids in common solvents; and nature of the compensating cation (sodium, potassium, more specifically, the catalyst is active only on five calcium). membered rings. Among the class of smectites can be mentioned: It is an object of the present invention to provide a montmorillonites of the formula new process for producing acid anhydrides which 60 avoids the disadvantages of previously-known pro cesses. A further object of the present invention is to provide a new catalyst for the cyclization of di-acid to beidellites of the formula (Sia. Al)Al2010(OH)2, form internal anhydride. M Additional objects and advantages of the invention 65 nontronites of the formula (Sia-Al)Fe2010(OH)2, will be set forth in the description which follows, and in M-- part will be apparent from the description, or may be hectorites of the formula Sia(Mgs.--Li)010(OH)2. learned by practice of the invention. The objects and M-x 5,260,456 3 4. Stevensites of the formula Sia(Mg3-)010(OH)2, M-- H-- per half matrix for smectite clay, that is at least 50 saponites of the formula (Sia-Al)Mg3010(OH)2, to 150 millieduivalents of acid to 100 g of smectite clay. M-- The preferred catalysts are those wherein the clay is fluorohectorites of the formula acidified in an aqueous acidic medium and then dried at low temperature. While drying temperatures of about 200° C. are acceptable for physical dewatering of the clay catalyst, it is preferred that a drying temperature Sauconites of the formula (Sia-Al) lower than 100° C. be used, and preferably lower than 50° C. Dewatering at these lower temperatures may be (Mg32n)00(OH)2, M -- O carried out either by lyophilisation or by vacuun dry Among the smectites, the montmorillonites are par ing, or treating with a hydrophilic solvent such as alco ticularly preferred for use within the scope of the pres hol or ketone. ent invention. Moreover, among the montmorillonites According to a second process of acid treatment, the are proprietary clays which are already acidic. For 15 clay is treated with an ammonium salt followed, for example, the following clays can be used: example, by calcination, preferably at a low tempera product KSF, marketed by Sud-Chemie (Munich), ture, to eliminate annonia and leave on the clay only product K 10 marketed by Sud-Chemie. the protons H -- originating from the ammonium salt. Clay KSF has a surface area of 20 to 40 m2/g and a Calcination is preferably carried out at a temperature density of 800 to 850 g/1.