CS240640B1 - Cyclopentadienyl complexes of low-grade titanium - Google Patents

Abstract

Cyclopentadienyl complexes of lower valent titanium formed by the interaction of a bis(cyclopentadienyl)dichlorotitanium complex bound to the surface of a porous or non-porous inorganic material A, where A represents silica, alumina, titanium dioxide, glass, ceramics or aluminosilicates, via a spacer of the general formula -O-Si-(CH^) where n represents an integer from 1 to 12 and an organometallic reagent of the general formula M-R, where M represents a lithium atom, sodium, potassium or a MgBr or MgCl group and R represents an alkyl of 1 to 5 carbon atoms or an aryl of 6 to 10 carbon atoms. Cyclopentadienyl complexes of lower valent titanium can be used as olefin hydrogenation catalysts.

Description

The present invention relates to cyclopentadienyl complexes of low-valent titanium which are chemically bonded to the surface of inorganic materials.

It is known that soluble complexes of low-valent titanium can serve as hydrogenation catalysts. For technical practice, it seems desirable to immobilize these complexes so that they can be removed from the reaction mixture and reused after the reaction. The compounds of the invention meet this requirement.

The present invention relates to the cyclopentadienyl complexes of the low-titanium titanium formed by the interaction of the bis (cyclopentadienyl) dichlorotitanium complex bound to the surface of the porous or non-porous inorganic material A (where A is silica, alumina, titanium dioxide, ceramics, glass or alumosilicates)

-O-Si- (CH ₂ ) _n wherein n represents an integer from 1 to 12 and an organometallic reagent of formula

M-R wherein M represents a lithium, sodium, potassium or group atom

MgBr or MgCl

R is alkyl of one to five carbon atoms, aryl of 6 to 10 carbon atoms.

The complexes thus prepared can be used as a catalyst for the hydrogenation of the C = C bond.

These materials can be prepared in one step, reducing the tetravalent titanium to reduce the number of ligands in the coordinating sphere of the transition metal atom, thereby forming a complex with a reduced oxidation degree of titanium.

The starting materials, i.e. the inorganic materials, contain on their surface a bis (cyclopentadienyl) dichlorotitanium complex bonded via the -O-Si- (CH 2) _n - group (where n represents an integer from 1 to 12) can be readily prepared according to U.S. Pat. AO 240 639 by the interaction of a cyclopentadienyltrichlorotitanium complex with a cyclopentadienyl anion bound to the surface of an inorganic material, the preparation of which is described in U.S. Pat. AO 240,634.

The actual preparation of the cyclopentadienyl complexes of the lower-valent titanium consists in the reduction of the bis (cyclopentadienyl) dichlorotitanium complex. Organometallic compounds such as methyl lithium, butyl lithium, naphthyl alkali, naphthyl natrium or Grignard reagents may be used as reducing agents,

Cl

-O-Si- (CH ₂ ) _n -C ₅ H ₄ TiC ₅ H ₅ reducing agent

-O-Si- (CH 2) -C_H.TiC _c H _c 2 n 5 4 o □

Wherein n is an integer from 1 to 12.

It is preferred to carry out the reaction in an inert atmosphere such as argon and in a solvent not reacting with organometallic reagents such as toluene, benzene, tetrahydrofuran at reduced, elevated or room temperature. After the reaction, it is appropriate to wash the obtained material several times with a solvent which can be removed under reduced pressure and dried under vacuum.

The immobilized low-titanium cyclopentadienyl complexes thus prepared can be used as the olefin hydrogenation catalyst. For example, the hydrogenation can be carried out under mild conditions (at a temperature of 0-70 ° C and a pressure of 0.5 to 1.5 MPa), and upon completion of the hydrogenation, the solid heterogeneous catalyst can be separated from the reaction mixture and reused.

The following examples characterize the compounds of the invention without limiting or limiting them.

Example 1

216 mg of silica was added to the reaction flask together with 15 ml of toluene, the surface of which was modified with -O-Si-C 1 H 4 -C 4 H 4 Ti (Cl 2) C 8 H 3. complex containing 0.7% titanium. 1.5 ml of a 0.7 M solution of methyl lithium in hexane was added in one portion. The mixture was shaken for 1.5 h. Then the inorganic material was filtered and washed three times with 100 ml of toluene and dried under vacuum. The anisotropic EPR spectrum of the product obtained showed signals with g = 1.999 and 3+ g = 1.945 attributable to stabilized Ti complexes.

Example 2

Example 1 was repeated except that alumina bearing on its surface an -O-Si- (CH ₂ ) 4 C 8 H 6 Ti (Cl) 2 ^ -5 ^ complex containing 0.64% titanium and as reducing agent was used instead of silica. reagent was used instead of methyl lithium solution (CHg) ₂ CHMgBr in dibutyl ether. The same signals as in Example 1 were found in the anisotropic spectrum of the product obtained.

Example 3

Example 1 was repeated except that instead of a silica surface modified grouping _Si-CH2 C ^ H ^ Ti (Cl) ₂ was used CjHg silica surface modified group Si- (CH ₂₎ j C ^ H ^ Ti ( Cl _{2 2} C ₅ H 2 containing 0.54% titanium and C 1 H 4 Na 2 was used as reducing agent. The anisotropic EPR spectrum of the obtained material showed the same signals as in Example 1.

Example4

Example 1 was repeated except that titanium dioxide containing 0.41% titanium was used in place of silica and a solution (CH 2 Cl 2 CH 2 MgCl 2 in dibutyl ether) was used as the reducing agent. The same signals as in Example 1 were found in the EPR spectrum. .

Example 5

Example 2 was repeated except that ceramic porcelain containing 0.1% titanium was used in place of alumina and a solution of C 4 H 4 Na in hexane was used as reducing agent. The material obtained showed the same signals in the EPR spectrum as in Example 1.

Example 6

Example 1 was repeated except that a molecular sieve A5 containing 0.06% titanium was used in place of silica and the product showed the same signals in the EPR spectrum as found in Example 1.

Example7

Example 1 was repeated except that a porous glass containing 0.7% titanium was used instead of silica and a solution of C ^ gHHHK in tetrahydrofuran was used as reducing agent. The same signals as in Example 1 were found in the EPR spectrum of the resulting material.

Since this was merely a change in the valency of the anchored titanium complex in the sense of the equation on page 2, practically quantitative yields were obtained in Examples 1 to 7, with minor losses (1 to 3%) due to mechanical filtration losses. Also the content of anchored titanium after reduction is in the range of analytical determination errors.

Example

Hydrogenation of 1-octene mmol of 1-octene in 10 ml of toluene was hydrogenated in a hydrogenation apparatus in the presence of 0.06 mmol of heterogeneous cyclopentadienyl lower-valent titanium complexes prepared according to Examples 1, 2, 3, 5 at a temperature of 60. -octene to octane.

C and a pressure of 0.1 MPa.

Catalyst from Example

Reaction time (min)

Conversion (")

1.

2.

3.

4.

Claims (1)

OBJECT OF THE INVENTION Low-titanium cyclopentadienyl complexes formed by the interaction of the bis (cyclopentadienyl) dichlorotitanium complex bound to the surface of the porous or non-porous inorganic material A, wherein A is silica, alumina, titanium dioxide, glass, ceramic or alumosilicates, -O-Si- (CH ₂ ) _n where n represents an integer Γ to. 22 and an organometallic reagent of the formula M-R wherein M represents a lithium, sodium, potassium or group atom MgBr or MgCl a R is alkyl of 1 to 5 carbon atoms, aryl of 6 to 10 carbon atoms. Severography, n. P., MOST