EP0000617B1

EP0000617B1 - Production of unsubstituted and substituted indene.

Info

Publication number: EP0000617B1
Application number: EP78300066A
Authority: EP
Inventors: Robert Karl Grasselli; Joseph Peter Bartek
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1977-07-18
Filing date: 1978-06-22
Publication date: 1981-08-12
Also published as: AT362779B; AU3727878A; DE2860929D1; EP0000617A1; IT1195255B; ATA512178A; ZA783692B; JPS5439060A; JPS6138176B2; US4143082A; AU519566B2; IT7825217A0; CA1092163A; DK320978A

Description

The present invention relates to a novel catalytic technique for making unsubstituted and substituted indene.
Many patents directed to copolymers containing indene as an essential component have been published. Unfortunately, at the present time there is no simple straight forward and economical technique for producing indene monomer.
The invention is concerned with the problem of making unsubstituted or substituted indene in a simple economic and straightforward manner.
In United Kingdom Patent No. 761,625 there is described a non-catalytic process for the conversion of indanes and/or alkyl indanes to the corresponding indenes. In United Kingdom Patent No. 1218903 the conversion of indane or an alkyl indene to the corresponding indene by a two-stage oxydehydrogenation process utilizing a catalyst in the second stage is described.
It has been found that suitable indene precursors may be converted to unsubstituted and substituted indene by a dehydrogenation process which involves contacting the indene precursors with a phosphate catalyst at elevated temperature in the presence of an oxygen donor.
The invention therefore provides a process for producing unsubstituted or substituted indene by the oxydehydrogenation of an unsubstituted bicyclic indene precursor or a bicyclic indene precursor substituted with C₁ to C4 alkyl, C₁ to C₄ alkenyl or phenyl group, said precursor being more saturated than indene, characterised in that the indene precursor is contacted with a phosphate catalyst in the presence of an oxygen donor at a temperature of at least 100°C.
The present invention is based on the observation that a wide variety of phosphate-containing inorganic compounds will catalyse the catalytic removal of hydrogen from indene precursors more saturated than indene in the presence of an oxygen donor so as to yield indene and substituted indene as a product. Thus it is possible in accordance with the present invention to produce indene and substituted indene by a simple and straightforward catalytic dehydrogenation reaction.
In accordance with the invention, unsubstituted indene and substituted indenes are produced from bicyclic and substituted bicyclic indene precursors more saturated than indene. The substituted bicyclic compounds contain one or more alkyl or alkenyl groups having from 1 to 4 carbon atoms or phenyl groups attached to one or both rings. The substituted indenes produced from these precursors normally have the corresponding alkyl, alkenyl or phenyl groups attached, although thay may have fewer groups, or may have groups with fewer carbon atoms attached.
Examples of precursors which may be converted into indene or substituted indenes in accordance with this invention include indane, alkyl indanes in which the alkyl groups have from 1 to 4 carbon atoms especially methyl indanes, tetrahydroindene (especially the bicyclo{4.3.0}nona-3,7-diene isomer), alkyl tetrahydroindenes in which the alkyl groups have from 1 to 4 carbon atoms, hexahydroindene, hexahydroindane and vinyl norbornene (5-vinyl bicyclo{2.2.1 }-2-heptene).
In carrying out the process of the invention the indene precursor which is discussed above is contacted in the presence of an oxygen donor with a catalyst comprising a phosphate, i.e. a salt of one of the phosphoric acids. Any type of phosphoric acid salt can be employed be it an orthophosphate, a hypophosphate, a metaphosphate, a pyrophosphate, or other polyphosphate. Moreover, in the foregoing types of phosphates, any cation can be employed, and in addition different types of cations can be employed in a single phosphate. For example, an orthophosphate catalyst which can be used in accordance with the present invention can contain one, two or three different metals depending, of course, upon valence requirements, as well as hydrogen. Similarly, the other types of phosphates can contain one or more different metal cations as well as hydrogen.
Preferred catalysts for use in the process of the invention are those of the following formula:
wherein M is one of more elements selected from Mg, Sr, Ca, Ba, La, Ce, other rare earths, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Pb, Bi, Te, B, Al, Rh, Sb, As, U, Th, Ge and Ru; and
wherein 0.1 x < Σa < 10x, wherein Ea represents the sum of subscripts a of all of the metal ions and y is a number such that the valence requirements of the metal ions for oxygen is satisfied.
In the foregoing catalysts, minor amounts (i.e. not more than 10% on a phosphorus atom basis) of alkali metals, noble metals, silver, gold and/or tellurium may be added.
In a more specific embodiment, the catalysts employed in the inventive process are characterized by the following formula:
wherein M is at least one of Bi, Fe, Ni, Co, Cr, La, Sn, Mg, Ca, Ce, U, Sb;
wherein M' is at least one element selected from Ge, Pb, Mo, W, Sr, Ba, Re, Th, As, Te, and elements selected from groups IA, IB, IIB, IIIA and VB of the Periodic Table; and
wherein 0.1 < a <_ 16, 0≤ b ≤ 16, 0.5 ≤ x≤ 16 and y is a number such that the valence requirements of the remaining elements for oxygen are satisfied.
In this embodiment of the invention, particularly preferred cations are Bi, Fe, Co, Cr, La, Sn, Mg, U, Sb, Mo, W and Te when used in combinations of two or more.
Still another class of catalysts which has been found especially useful in accordance with the invention is characterized by the formula:
wherein M is at least one element selected from Mg, Ca, Co, Ba, Sr, Fe(II), Mn(II); Ni, Cu, Zn and Pb;
wherein X is at least one of Fe(III), La, Cr, Ce, other rare earths, B, Al, Ru, and Rh; and
wherein 0 ≤ Ea + Eb ≤ 1 Ox and 0.5 ≤ x ≤ 100, wherein ∑a + ∑b represents the sum of all subscripts a + b and y is a number such that the valence requirements of all the other elements for oxygen is satisfied.
Specific catalysts which have been found to be particularly useful in the process of the present invention include
The catalysts used in the process of the present invention can be used either as on their own or the catalysts can be supported on suitable inert supports such as alpha alumina, Alundum (Registered Trade Mark), silica, silicon carbide, titania, zirconia and the like. In addition, phosphate support materials such as BP0₄, TiP₂O₇, ZrP₂0₇, SbPÚ₄ and AIP0₄ can also be employed, wherein the catalyst support will exhibit some catalytic action of its own. The active catalytic component can be incorporated with the support by any known technique such as coprecipitation, impregnation or coating with a wet slurry, a partially dry powder or pelleting. The size of the catalyst particles is not critical and can vary between wide limits. For example, the catalyst particle size may be extremely small (e.g. microspheroidal) so that the catalyst can be employed in a fluid-bed reactor or the catalyst can be significantly larger in particle size so that the catalyst can be employed in a fixed-bed reactor.
The dehydrogenation reaction according to the invention is carried out in the presence of an oxygen donor. As an oxygen donor, elemental oxygen, O2, is normally employed. In particular, air is normally employed as a feed since it is cheapest and most convenient. Other compounds which will serve as oxygen donors in a dehydrogenation reaction, however, can also be employed. For example, SO₂, COS and HOCI can also be employed.
The amount of oxygen donor fed to the reaction vessel should at least be the stoichiometric amount necessary to react with all of the hydrogen to be withdrawn from the indene precursor feed. Of course, less than the stoichiometric amount can be fed to the reactor, but this will simply decrease the efficiency of the process. Preferably, the amount of oxygen donor fed to the reaction vessel is at least twice, preferably 2 to 5 times, the stoichiometric amount necessary to react all of the hydrogen withdrawn from the indene precursor.
In addition to the foregoing components, a gaseous promoter known to increase oxidation rates can also be fed to the reaction vessel for improving the efficiency of the dehydrogenation reaction according to the invention. In this regard, it is well known that certain compounds such as halides (gaseous HCI, HBr, C1₂, Br₂, alkyl halides of the formula C_xH_YX_Z wherein X is halide and x is 1-5, y is 0-16, and z is 1-16 and so forth) serve to promote various types of dehydrogenation reactions. In accordance with the present invention, such gaseous promoters can also be fed to the reaction vessel normally together with the oxygen donor (which is normally in a gaseous state) for increasing the efficiency of the reaction according to the invention. When a gaseous promoter is employed, it is preferable that the amount of gaseous promoter is less than 10%, in particular preferably less than 5%, of the oxygen donor fed to the reaction vessel in order that the hydrocarbon feed is not halogenated.
The gaseous materials fed to the reaction vessel (i.e. the oxygen donor and optionally the gaseous promoter) can also contain a gaseous diluent. Any gas inert to the reaction and catalyst can be employed as the gaseous diluent. Preferred gaseous diluents include N₂, CO₂, H₂0, combustion gases and light hydrocarbon gases (e.g. methane). Methane is an especially preferred gaseous diluent since it suppresses explosions and hence allows more oxygen donor to be tolerated by the system without fear of explosion. When the oxygen donor-is O2, the amount of inert diluent should be in the range of 0 to 20 times the amount of O2 fed to the reaction vessel. When other oxygen donors are employed, a stoichiometrically corresponding amount of inert diluent can be employed.
The reaction according to the invention can be carried out either in fixed-bed mode or fluid-bed mode. In fixed-bed mode, the liquid hourly space velocity of the indene precursor feed is from 0.01 to 10, preferably 0.05 to 1, optimally 0.25 hours-1. The contact time for the reactants in the inventive process is normally from 0.1 to 20 seconds, preferably 2 to 10 seconds. The reaction pressure is normally maintained at approximately atmospheric pressure, although a lower or higher pressure can be employed if desired. Indeed, any practicable pressure can be utilized.
The reaction temperature must be at least 100°C and is normally maintained between 100°C and 650°C, preferably 250°C to 550°C. In this connection, it has been found that the preferred reaction temperature varies depending upon the indene precursor to be processed with a temperature range of 350°C to 600°C being preferred for indane dehydrogenation and 200° to 550°C being preferred for dehydrogenation of a more saturated precursor.
The following examples illustrate the invention.

Examples 1 to 11

15 cc of the catalysts set forth in the following Table I were charged into a fixed-bed, 1.27 cm, outside diameter, stainless steel, tubular reactor. Each of these catalysts was prepared by mixing an appropriate amount of each of the metals in question in the form of an aqueous nitrate solution with an aqueous solution of NH₄H₂PO₄ to form a precipitate, drying the precipitate and calcining the dried precipitate at a temperature of from 500 to 600°C in air for a period of 120 to 1200 minutes. The particle size of each of the catalysts was between 0.833 mm and 0.417 mm mesh.
In each example, a mixture of indane, approximately five parts air and three parts N₂ for each part indane vapour was fed to the reactor. The reactants were fed at a rate such that the liquid hourly space velocity of indane was 0.24 hr-¹ and the contact time of the reactants was about three seconds. The reaction temperature was maintained at 550°C and the reaction pressure was one atmosphere. The following results were obtained:
As will be noted, the single pass yields realized in the foregoing experiments were in excess of 65% and selectivities in excess of 80% were obtained. It will thus be appreciated that indane was dehydrogenated to indene with very favourable per pass conversions and selectivities in a very simple manner.

Examples 12 to 17

Tetrahydroindene (bicyclo{4.3.0}nona-3,7 diene) was oxydehydrogenated to indene by the same procedure and under the same conditions as in Examples 1 to 11 except that the reaction temperature was 470°C and the catalysts used are those specified in Table II below. These catalysts were also prepared in the same way as the catalysts used in Examples 1 to 1 1. The results of Examples 12 to 17 are set forth in the following Table II.
As can be seen, total oxydehydrogenation selectivities in the foregoing examples were in excess of 60% and cracking of the starting material is quite small. Moreover, the recovery on a total carbon balance cases is quite high, 82-92%.

Example 18

The procedure of Examples 12 to 17 was repeated using vinyl norbornene (5-vinyl-bicyclo{2.2.1 - 2-heptene) as the feed and a catalyst comprising CO₇La_1.5Bi₂P₁₂0y as a catalyst. The per pass conversion to indene was 18% while the per pass conversion to indane was 5%. Isomerization also occurred to tetrahydroindene in an amount of 14% per pass conversion. 50% of the product was cracked predominantly to butadiene and cyclopentadiene, while approximately 10% of the reactant was combusted.

Examples 19 to 40

Additional experiments were conducted in which tetrahydroindene was oxydehydrogenated to indene in the presence of air in a fixed-bed reactor. The results of these tests are summarized in the Table III in which C.T. means contact time.
Indene is produced with high yields in substantially all of the foregoing examples.
In addition to the various indene precursors described above in the examples as starting materials, substituted indene precursors, especially alkyl substituted indene precursors of the foregoing type in which the alkyl groups have from 1 to 4 carbon atoms can also be employed. Furthermore, the hydrocarbon starting material can comprise a mixture of different indene precursors as well as a single indene precursor. In this regard the reaction product obtained by carrying out a Diels-Alder reaction on cyclopentadiene and butadiene, which normally contains both tetrahydroindene and vinyl norbornene, could be directly processed in accordance with the present invention to form indene. It is also possible and may be preferable in accordance with the present invention to recycle indene precursor byproduct of the process of the invention in order to treat further these indene precursors to form indene. In addition, since cyclopentadiene and butadiene are the predominant cracking products of the inventive reaction, it is also possible to subject these byproducts to a Diels-Alder reaction to form tetrahydroindene and vinyl norbornene which in turn can be used as a starting material in the process of the invention.
The phosphate catalysts employed on the inventive process can be prepared in any conventional manner, such as by using a nitrate solution as discussed above or any other convenient technique.

Claims

1. A process for producing unsubstituted or substituted indene by the oxydehydrogenation of an unsubstituted bicyclic indene precursor or a bicyclic indene precursor substituted with C₁ to C₄ alkyl, C₁ to C₄ alkenyl or phenyl group, said precursor being more saturated than indene, characterised in that the indene precursor is contacted with a phosphate catalyst in the presence of an oxygen donor at a temperature of at least 100°C.

2. A process as claimed in claim 1 characterised in that the reaction temperature is 100° to 650°C.

3. A process as claimed in claim 2 characterised in that the reaction temperature is 250° to 550°C.

4. A process as claimed in any of claims 1 to 3 characterised in that the indene precursor is one or more of the following; indane, an alkyl indane in which the alkyl group has from 1 to 4 carbon atoms, tetrahydroindene, an alkyl tetrahydroindene in which the alkyl group has from 1 to 4 carbon atoms, hexahydroindene, hexahydroindane and vinyl norbornene.

5. A process as claimed in any of claims 1 to 4 characterised in that the phosphate catalyst is represented by the formula:

wherein M is one of more elements selected from Mg, Sr, Ca, Ba, La, Ce, other rare earths, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Pb, Bi, Te, B, AI, Rh, Sb, As, Ge, U, Th and Ru; and

wherein 0.1x ≤ ∑a ≤ 1Ox, wherein ∑a represents the sum of subscripts a of all of the metal ions and y is a number such that the valence requirements of the metal ions for oxygen is satisfied.

6. A process as claimed in any of claims 1 to 4 characterised in that the phosphate catalyst has the formula

wherein M is at least one of Bi, Fe, Ni, Co, Cr, La, Sn, Mg, Ca, Ce, U, Sb,

wherein M' is at least one element selected from Ge, Pb, Mo, W, Sr, Ba, Re, Th, As, Te, and elements selected from Groups IA, IB, IIB, IIIA and VB of the Periodic Table, and

wherein 0.1 < a < 16, 0 ≤ b≤ 16, 0.5 ≤ x 5≤16 and y is a number such that the valence requirements of the remaining elements for oxygen are satisfied.

7. A process as claimed in claim 6 characterised in that the phosphate catalyst contains at least one of Bi, Fe, Co, Cr, La, Sn, Mg, U and Sb, and further characterised in that the catalyst contains at least one of Mo, W and Te.

8. A process as claimed in any of claims 1 to 4 characterised in that the phosphate catalyst is represented by the formula

wherein M is one or more elements selected from Mg, Ca, Co, Ba, Sr, Fe(II), Mn(II), Ni, Cu, Zn and Pb.

wherein x is at least one of Fe(III), La, Cr, Ce, other rare earths, B, Al, Ru and Rh, and

wherein O ≤ ∑a + ∑b ≤ 1 Ox and 0.5 ≤ + ≤ 100, wherein Σa + Σb represents the sum of all subscripts a + b and y is a number such that the valence requirements of the other elements for oxygen is satisfied.

9. A process as claimed in any of claims 1 to 4 in which the catalyst is one of the following namely: