Diphosphite having an open 2,4-methylated external unit

Abstract

To provide novel ligands that exhibit increased n / iso selectivity in the hydroformylation of olefins.SOLUTION: The present invention discloses a diphosphite having an open, 2,4-methylated outer unit, illustrated by a compound of the following structure, and use thereof in hydroformylation.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a phosphite having an open 2,4-methylated external unit and its use in hydroformylation.

Background Art

[0002] Phosphorus-containing compounds play an important role as ligands in many reactions such as hydrogenation, hydrocyanation, and hydroformylation.

[0003] The reaction of an olefin compound, carbon monoxide, and hydrogen in the presence of a catalyst to obtain an aldehyde having one or more carbon atoms is known as hydroformylation or the oxo process. In these reactions, compounds of transition metals of Group VIII of the periodic table are frequently used as catalysts. Known ligands include, for example, compounds of the phosphine, phosphite, and phosphonite groups, each containing trivalent phosphorus P III The current overview of olefin hydroformylation can be found in R. Franke, D. Selent, A. Börner, "Applied Hydroformylation", Chemical Reviews, 2012, DOI: 10.1021 / cr3001803.

[0004] The following compound is shown in Example 10 on page 98 of Patent Document 1.

Chemical Formula

[0005] The said compound (2) is used as a ligand in the hydroformylation of 1-butene.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Non-Patent Documents

[0007]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The technical object of the present invention is to provide a novel ligand with improved n / iso selectivity in the hydroformylation of olefins as compared to ligands known from the prior art.

[0009] This object is achieved by the compound according to claim 1. Compound of structure (I).

Chemical Formula

[0010] In one embodiment, R 1 , R 3 is selected from -H, -(C1-C 12 )-alkyl. In one embodiment, R 1 , R 3 is -(C1-C 12 )-alkyl. In one embodiment, R 1 , R 3 is -tBu. In one embodiment, R 1 , R 3 are the same radical. In one embodiment, R 2 , R4 is selected from -H, -O-(C1-C 12 )-alkyl. In one embodiment, R 2 , R 4 is -O-(C1-C 12 )-alkyl. In one embodiment, R 2 , R 4 is -OMe. In one embodiment, R 2 , R 4 are the same radical. In one embodiment, R 1 , R 2 , R 3 , R 4 are not all -CH3 at the same time. In one embodiment, the compound has structure (1). [Chemical formula]

[0011] The use thereof for the catalysis of the hydroformylation reaction, as well as the compound itself, is claimed. Use of the above compound in a ligand-metal complex for the catalysis of the hydroformylation reaction.

[0012] Furthermore, a method of using the above compound as a ligand is claimed. a) First, an olefin is introduced, b) The above compound and a substance containing a metal selected from Rh, Ru, Co, Ir are added, c) H2 and CO are introduced, d) A method comprising heating the reaction mixture of steps a) to c) to convert the olefin to an aldehyde. In a preferred embodiment, the metal is Rh.

[0013] The ligand can also be used in excess, and each ligand does not exist alone in the form of a ligand-metal complex. Instead, it may be present in the reaction mixture as a free ligand. The reaction is carried out under normal conditions. Temperature: 80 °C to 160 °C and pressure: 10 to 60 bar are preferred. Temperature: 100 °C to 140 °C and pressure: 20 to 50 bar are particularly preferred.

[0014] The reactants for hydroformylation in the process of the present invention are olefins or mixtures of olefins, in particular monoolefins having 2 to 24, preferably 3 to 16, more preferably 3 to 12 carbon atoms and having terminal or internal C-C double bonds, such as 1-propene, 1-butene, 2-butene, 1- or 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 1-, 2- or 3-hexene, C6 olefin mixture obtained by dimerization of propene (dipropene), heptene, 2- or 3-methyl-1-hexene, octene, 2-methylheptene, 3-methylheptene, 5-methyl-2-heptene, 6-methyl-2-heptene, 2-ethyl-1-hexene, C8 olefin mixture obtained by dimerization of butene (di-n-butene, diisobutene), nonene, 2- or 3-methyloctene, C9 olefin mixture obtained by trimerization of propene (tripropene), decene, 2-ethyl-1-octene, dodecene, C obtained by tetramerization of propene or trimerization of butene (tetrapropene or tributene) 12 olefin mixture, tetradecene, hexadecene, C obtained by tetramerization of butene (tetrabutene) 16 olefin mixture, and olefin mixtures having various numbers (preferably 2 to 4) of carbon atoms produced by co-oligomerization of olefins.

[0015] The process of the present invention using the ligand of the present invention can be used for the hydroformylation of α-olefins, terminal branched olefins, internal olefins, and internal branched olefins. The present invention will be described in detail below with reference to exemplary embodiments.

Embodiments for Carrying Out the Invention

[0016] Operation Procedure General Analysis All of the following preparations were carried out under an inert gas using standard Schlenk techniques. The solvents were dried with appropriate desiccants before use. The product was characterized by NMR spectroscopy. Chemical shifts (δ) are reported in ppm. 31 The 31P NMR signals were represented as follows: SR 31 P = SR 1 H*(BF 31 P / BF 1 H) = SR 1 H*0.4048.

[0017] Synthesis (1):

Chemical Structure

[0018] In a glove box, 9 g (0.01 mol) of diorganophosphite dichlorophosphite was weighed into a safe 250 mL volumetric Schlenk flask, then evacuated and dissolved in 75 mL of dry toluene. In a second safe 250 mL volumetric Schlenk flask, 2.5 g (0.02 mol) of 2,4-dimethylphenol and 3 mL (0.022 mol) of degassed triethylamine were dissolved in 50 mL of toluene. The chlorophosphite solution was added dropwise to the phenol-triethylamine solution slowly and continuously over 1.5 hours at room temperature. The reaction mixture was stirred overnight at room temperature. The reaction mixture was heated to 80 °C. After 18 hours, the reaction mixture was filtered through a frit, and the filtrate was concentrated at 40 °C under an oil pump vacuum. Subsequently, the solid was dried under an oil vacuum pump for 18 hours. Then, the solid was pulverized and stirred in 50 mL of dry ACN. Then, the precipitated white solid was removed by filtration. Purity 96%, Yield 48%.

[0019] Synthesis (2) (Comparative Ligand)

Chemical Structure

[0020] In a glove box, 9 g (0.01 mol) of diorganophosphite dichlorophosphite was weighed into a safe 250 mL capacity Schlenk flask, then evacuated and dissolved in 75 mL of dry toluene. In a second safe 250 mL capacity Schlenk flask, 2.2 g (2.1 mL, 0.02 mol) of 2-methylphenol was weighed and dried at room temperature for 12 hours using an oil vacuum pump. 50 mL of dry toluene and 2.2 g (= 3 mL, 0.022 mol) of degassed triethylamine were added with stirring and dissolved. The dichlorophosphite was added to the phenol-triethylamine solution at room temperature over 1.5 hours. The reaction mixture was stirred at room temperature for 2 hours and then heated to 80 °C. The reaction mixture was stirred at this temperature for 15 hours, then 1.5 mL (0.011 mol) of triethylamine was weighed in three times and stirring was continued for another 15 hours. Ammonium chloride was removed by frit, washed with 1 × 10 mL of dry toluene, and concentrated to dryness. The solid was dried at room temperature for 15 hours and stirred with 40 mL of degassed acetonitrile. The precipitated white solid was removed by frit, the Schlenk flask was post-rinsed twice with 10 mL of ACN, dried, and introduced into the glove box. Yield: 90%, Purity: 95%.

[0021] Catalyst experiment Hydroformylation was carried out in a 16 mL capacity autoclave manufactured by HEL Group (Hartfordshire, UK) equipped with a pressure holding valve, a gas flow meter, and a sparging stirrer. The n-octene used as the substrate (an octene isomer mixture from Oxeno GmbH, 1-octene: 3%, cis + trans-2-octene: 49%, cis + trans-3-octene: 29%, cis + trans-4-octene: 16%, structural isomer octene: 3%) was heated under reflux over sodium for several hours and distilled under argon.

[0022] The experimental reaction solution was prepared in advance under an argon atmosphere. For this purpose, 0.0021 g of Rh(acac)(CO)2 and the corresponding amount of phosphite compound were weighed and filled with 8.0 mL of toluene. The mass of toluene introduced in each case was measured for GC analysis. Then, 1.80 g of n-octene (16 mmol) was added. Next, the prepared solution was introduced into an autoclave, and the autoclave was flushed three times with argon and three times with synthesis gas (Linde, H2(99.999%):CO(99.997%) = 1:1). Then, the autoclave was heated to the desired temperature at a total pressure of 10 bar while stirring (at 900 rpm). When the reaction temperature was reached, the pressure of the synthesis gas was raised to 20 bar, and the reaction was carried out at a constant pressure for 4 hours. At the end of the reaction time, the autoclave was cooled to room temperature, depressurized while stirring, and flushed with argon. At the end of the reaction, 0.5 mL of each reaction mixture was removed, diluted with 4 mL of pentane, and analyzed by gas chromatography (HP5890 Series II Plus, PONA, 50 m × 0.2 mm × 0.5 μm). Residual olefins and aldehydes were quantitatively measured relative to the solvent toluene as an internal standard.

[0023] Results of the Catalyst Experiment Reaction Conditions: [Rh]: 120 ppm, L:Rh = 1:2, Pressure: 20 bar, Temperature: 120 °C, Time: 4 hours [Table 1]

[0024] Definition of Selectivity: For hydroformylation, there is an n / iso selectivity, which is the ratio of linear aldehyde (=n) to branched aldehyde (=iso). The selectivity for n-aldehyde in this specification means that this amount of linear product was formed. The remaining percentage corresponds to the branched isomer. Thus, at 50% regioselectivity, n-aldehyde and iso-aldehyde are formed in equal ratios. The compound (1) of the present invention has increased n / iso selectivity compared to the comparative ligand (2). The experiments conducted have demonstrated that the stated objectives are achieved by the compounds of the present invention.

Claims

Compound having structure (1). [Chemical 2] Claim 2 Use of the compound according to claim 1 in a ligand-metal complex for the catalysis of the hydroformylation reaction. Claim 3 a) First, introducing an olefin, b) adding the compound according to claim 1 and a substance containing a metal selected from Rh, Ru, Co, and Ir, c) H 2 and CO are introduced, d) heating the reaction mixture of steps a) to c) to convert the olefin to an aldehyde.

Images