Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
  • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
  • C07D301/19—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with organic hydroperoxides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/063—Titanium; Oxides or hydroxides thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/08—Silica
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
  • B01J31/0272—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing elements other than those covered by B01J31/0201 - B01J31/0255
  • B01J31/0274—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing elements other than those covered by B01J31/0201 - B01J31/0255 containing silicon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
  • B01J31/38—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 of titanium, zirconium or hafnium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0238—Impregnation, coating or precipitation via the gaseous phase-sublimation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/08—Heat treatment
  • B01J37/10—Heat treatment in the presence of water, e.g. steam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2231/00—Catalytic reactions performed with catalysts classified in B01J31/00
  • B01J2231/70—Oxidation reactions, e.g. epoxidation, (di)hydroxylation, dehydrogenation and analogues
  • B01J2231/72—Epoxidation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
  • B01J35/51—Spheres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/61—Surface area
  • B01J35/615—100-500 m2/g
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0201—Impregnation
  • B01J37/0209—Impregnation involving a reaction between the support and a fluid

Definitions

• the present invention relates to the preparation of an epoxidation catalyst and to the process of preparing alkylene oxide with the help of such catalyst.
• An epoxidation catalyst is understood to be a catalyst which catalyses the manufacture of an epoxy group containing compound.
• a well known process comprises contacting a hydroperoxide and alkene with a heterogeneous epoxidation catalyst and withdrawing a product stream comprising alkylene oxide and an alcohol.
• Catalysts for the manufacture of an epoxy group containing compound are well known.
• EP-A-345856 describes the preparation of such catalyst comprising titanium in chemical combination with a solid silica and/or inorganic silicate.
• the preparation comprises (a) impregnating a silicium compound with a stream of gaseous titanium tetrachloride preferably comprising an inert gas, (b) calcining the obtained reaction product of step (a) , and (c) hydrolysis of the product of step (b) .
• the stream of inert gas also has the function of a carrier for the gaseous titanium tetrachloride. For such use, the gas is to be present in a relatively large amount .
• the present invention relates to a process for the preparation of an epoxidation catalyst, which process comprises impregnating a silicon containing carrier with a gas stream consisting of titanium halide.
• a catalyst of improved selectivity was obtained even though the carrier had been in contact with the same amount of titanium halide.
• the catalyst of the present invention is obtained by impregnating a silicon containing carrier.
• any silicon containing carrier is suitable for use in the preparation process according to the present invention.
• silicon containing carriers comprise zeolites.
• the silicon containing carrier is a silica carrier.
• Silica carriers will substantially consist of silicon dioxide. However, limited amounts of further compounds such as contaminants can be present as well. It is known that contaminants can influence the performance of the final catalyst.
• the silica carrier for use in the present invention preferably contains at most 1200 ppm of sodium, more specifically at most 1000 ppm of sodium. Further, the silica carrier preferably comprises at most 500 ppm of aluminium, at most 500 ppm of calcium, at most 200 ppm of potassium, at most 100 ppm of magnesium and at most 100 ppm of iron. The amounts are based on amount of carrier.
• the silica carrier preferably is a silica gel.
• the silica gel carrier for use in the present invention can in principle be any carrier derived from a silicon containing gel.
• silica gels are a solid, amorphous form of hydrous silicon dioxide distinguished from other hydrous silicon dioxides by their micro- porosity and hydroxylated surface.
• Silica gels usually contain three-dimensional networks of aggregated silica particles of colloidal dimensions. They are typically prepared by acidifying an aqueous sodium silicate solution to a pH of less than 11 by combining it with a strong mineral acid. The acidification causes the formation of monosilicilic acid (Si (OH) ), which polymerizes into particles with internal siloxane linkages and external silanol groups.
• Si (OH) monosilicilic acid
• silica gel carrier would be silica support V432 and DAVICAT P-732, which are commercially available from Grace Davison.
• Silica gel carriers for use in the present invention preferably have a weight average particle size of at most 2 millimetres. Particle sizes which were found to be especially suitable were weight average particle, sizes of from 0.2 to 1.8 mm, more specifically of from 0.4 to 1.6 mm, most specifically of from 0.6 to 1.4 mm.
• the silicon containing carrier preferably has a low water content when contacted with the titanium halide.
• a low water content can be achieved in any way known to someone skilled in the art.
• a preferred way comprises drying the silicon containing carrier before impregnating the silicon containing carrier with the gas stream consisting of titanium halide.
• a suitable drying method comprises subjecting the silicon containing carrier to a temperature of from 200 to 700 °C. Surprisingly it has been found that drying under specific circumstances gives a further improved catalyst.
• the preferred drying conditions comprise drying the carrier at a temperature of from more than 200 to 300 °C. The drying is preferably carried out during of from 1 to 8 hours, preferably in the presence of an inert gas such as nitrogen.
• the preferred method has been described in more detail in co- pending patent application claiming priority of European application 02258294.4.
• Hydrolysis comprises treating the carrier with water or steam.
• the hydrolysis is carried out with steam.
• the hydrolysis treatment may comprise a washing treatment using an aqueous solution of a mineral acid, an aqueous solution of an ammonium salt or a combination thereof. Any water which might still be present after the hydrolysis, is preferably removed before treating the carrier further. Water is preferably removed by drying.
• the calcination is carried out at a relatively high temperature.
• a preferred calcination treatment comprises (a) calcining a silica gel carrier at a temperature of at least 400 °C, (b) hydrolysing the calcined silica gel carrier, (c) impregnating the hydrolysed carrier obtained in step (b) with a titanium-containing impregnating agent, and (d) calcining the impregnated carrier.
• the calcination of step (a) is carried out at a temperature of from 450 to 800 °C, more preferably of from 500 to 700 °C.
• the silica gel carrier for use in the present invention preferably has a surface area of at most 1000 m2/gram, more preferably at most 800 m2/gram, most preferably at most 500 m2/gram.
• Titanium halides which can be used in the process according to the present invention comprise tri- and tetra-substituted titanium complexes which have of from 1 to 4 halide substituents with the remainder of the substituents, if any, being alkoxide or amino groups.
• the titanium halide can be either a single titanium halide compound or can be a mixture of titanium halide compounds.
• the titanium halide comprises at least 50 %wt of titanium tetrachloride, more specifically at least 70 %wt of titanium tetrachloride.
• the gas stream consists of titanium tetrachloride.
• the present invention comprises impregnating the carrier with gas consisting of titanium halide.
• catalyst having higher selectivity for the desired alkylene oxide could be obtained if the silicon containing carrier was impregnated with gas consisting of titanium halide.
• the preparation according to the present invention is carried out in the absence of a carrier gas. Without wishing to be bound to any theory, it is thought that the carrier gas interferes with the impregnation. However, limited amounts of further gaseous compounds are allowed to be present during the contact between the silicon containing carrier and the gaseous titanium halide.
• the gas in contact with the carrier during impregnation preferably consists for at least 70 %wt of titanium halide, more specifically at least 80 %wt, more specifically at least 90 %wt, most specifically at least 95 %wt.
• Gaseous titanium halide can be prepared in any way known to someone skilled in the art.
• a simple and easy way comprises heating a vessel containing titanium halide to such temperature that the gaseous titanium halide is obtained.
• the impregnated carrier will be calcined and subsequently hydrolysed before being used as a catalyst. It is believed that calcination removes hydrogen halide, more specifically hydrogen chloride which is formed upon reaction of titanium halide and silicon compounds present on the surface of the silicon containing carrier.
• the optional calcination of the impregnated carrier generally comprises subjecting the impregnated carrier to a temperature of at least 500 °C, more specifically at least 600 °C. Preferably, the calcination is carried out at a temperature of at least 650 °C. From a practical point of view, it is preferred that the calcination temperature applied is at most 1000 °C.
• Hydrolysis of the impregnated and calcined carrier can remove Ti-halide bonds.
• the hydrolysis of the impregnated carrier will generally somewhat more severe than the optional hydrolysis of the carrier before impregnation. Accordingly, this hydrolysis of the impregnated carrier is suitably carried out with steam at a temperature in the range of from 150 to 400 °C.
• the hydrolysed impregnated carrier is subsequently silylated for instance by contacting the hydrolysed impregnated carrier with a silylating agent, preferably at a temperature of between 100 and 425 °C.
• Suitable silylating agents include organosilanes like tetra-substituted silanes with C]_-C3 hydrocarbyl substituents.
• a very suitable silylating agent is hexamethyldisilazane. Examples of specific suitable silylating methods and silylating agents are, for instance, described in US-A-3, 829, 392 and US-3,923,843 which are referred to in US-A-6, Oil, 162, and in EP-A-734764.
• titanium as metallic titanium
• the amount of titanium will normally be in the range of from 0.1 to 10% by weight, suitably of from 1 to 5% by weight, based on total weight of the catalyst.
• titanium or a titanium compound, such as a salt or an oxide is the only metal and/or metal compound present.
• alkylene oxides such as propylene oxide
• a hydroperoxide such as hydrogen peroxide or an organic hydroperoxide as the source of oxygen.
• the hydroperoxide can be hydrogen peroxide or any organic hydroperoxide such as tert-butyl hydroperoxide, cumene hydroperoxide and ethylbenzene hydroperoxide.
• the alkene will generally be propene which gives as alkylene oxide, propylene oxide.
• the catalyst prepared according to the present invention has been found to give especially good results in such process.
• the present invention further relates to a process for the preparation of alkylene oxide which process comprises contacting a hydroperoxide and alkene with a heterogeneous epoxidation catalyst and withdrawing a product stream comprising alkylene oxide and an alcohol and/or water, in which process the catalyst has been prepared according to the present invention.
• a specific organic hydroperoxide is ethylbenzene hydroperoxide, in which case the alcohol obtained is 1-phenyl ethanol.
• the 1-phenylethanol usually is converted further by dehydration to obtain styrene.
• Another method for producing propylene oxide is the co-production of propylene oxide and methyl tert-butyl ether ( TBE) starting from isobutane and propene.
• a further method comprises the manufacture of propylene oxide with the help of cumene.
• cu ene is reacted with oxygen or air to form cumene hydroperoxide.
• Cumene hydroperoxide thus obtained is reacted with propene in the presence of an epoxidation catalyst to yield propylene oxide and 2-phenyl propanol.
• the latter can be converted into cumene with the help of a heterogeneous catalyst and hydrogen. Suitable processes are described for example in WO 02/48126.
• the conditions for the epoxidation reaction according to the present invention are those conventionally applied.
• typical reaction conditions include temperatures of 50 to 140 °C, suitably 75 to 125 °C, and pressures up to 80 bar with the reaction medium being in the liquid phase.
• the silica gel carrier used in the examples had a surface area of 300 2/g and a weight average particle size of about 1 mm. Substantially all particles had a particle size between 0.6 and 1.4 mm.
• the dried silica gel carrier was contacted with a gas stream containing titaniumtetrachloride.
• the gas stream was obtained by heating titaniumtetrachloride to 200 °C with the help of an electrical heating system. Different gas streams were obtained by adding different amounts of nitrogen. At the end of each experiment, each silica carrier had been in contact with the same amount of titaniumtetrachloride.
• the impregnated catalysts thus obtained were calcined at 600 °C during 7 hours.
• the calcined catalysts were subsequently contacted with steam at 325 °C during 6 hours.
• the steam flow consisted of 3 grams of water per hour and 8 Nl of nitrogen per hour.
• the catalysts were silylated at 185 °C during 2 hours by being contacted with 18 grams of hexamethyldisilazane per hour in a nitrogen flow of 1.4 Nl per hour.
• the catalysts obtained were analysed for the amount of titanium deposited on the carrier.
• the selectivity of the catalysts was tested in a continuous epoxidation bench scale unit containing a number of vessels on automatic weight balances containing respectively the ethylbenzene hydroperoxide and propene feed streams, two high pressure pumps, a fixed bed reactor, a third pump for pumping a recycle stream over the reactor, means to maintain the reactor continuously at temperatures between 60 and 120 °C, a stripper to remove light boiling components like propene, a cooler and a vessel for receiving the product.
• the feeds were supplied to the reactor via the two high pressure pumps and mixed together before entering the reactor.
• the reactor was operated liquid full at
• the feed consisted of 40 %wt of propene, 20 %wt of ethylbenzene hydroperoxide and 40 %wt of ethylbenzene.
• the results obtained are given in Table 1.
• the selectivity is the molar ratio of propylene oxide formed to ethylbenzene hydroperoxide converted.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Inorganic Chemistry (AREA)
• Epoxy Compounds (AREA)
• Catalysts (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Priority Applications (1)

Applications Claiming Priority (4)

Publications (1)

Family

ID=32405785

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (3)

Family Cites Families (6)

• 2003
  • 2003-11-24 CA CA002508043A patent/CA2508043A1/en not_active Abandoned
  • 2003-11-24 EP EP03796044A patent/EP1567261A1/en not_active Withdrawn
  • 2003-11-24 MX MXPA05005699A patent/MXPA05005699A/es not_active Application Discontinuation
  • 2003-11-24 CN CN200380104860.XA patent/CN1720097A/zh active Pending
  • 2003-11-24 AU AU2003298312A patent/AU2003298312A1/en not_active Abandoned
  • 2003-11-24 WO PCT/EP2003/050875 patent/WO2004050233A1/en not_active Application Discontinuation
  • 2003-11-24 JP JP2004556324A patent/JP2006507932A/ja active Pending
  • 2003-11-24 BR BR0316825-5A patent/BR0316825A/pt not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events