New heterogeneous Rh-containing catalysts immobilized on a hybrid

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Applications of Polymer, Composite, and Coating Materials

New heterogeneous Rh-containing catalysts immobilized on a hybrid organic-inorganic surface for hydroformylation of unsaturated compounds Edward Rosenberg, Gorbunov Dmitry, Darya Safronova, Yu Kardasheva, Anton Maximov, and Eduard Karakhanov ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b02797 • Publication Date (Web): 06 Jul 2018 Downloaded from http://pubs.acs.org on July 7, 2018

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ACS Applied Materials & Interfaces

New heterogeneous Rh-containing catalysts immobilized on a hybrid organic-inorganic surface for hydroformylation of unsaturated compounds Dmitry Gorbunov,a Darya Safronova ,a Yulia Kardasheva ,a Anton Maximov,b Edward Rosenberg,*c Eduard Karakhanov a a

Department of Petroleum Chemistry and Organic Catalysis, Moscow State University, Moscow, 119991, Russia b c

Topchiev Institute of Petrochemical Synthesis RAS, Moscow, 119991, Russia

Department of Chemistry and Biochemistry, University of Montana, Missouls, MT 59812 *

[email protected]

KEYWORDS Hydroformylation, hybrid materials, polyamines, silica gel, rhodium ABSTRACT The anchoring of Rh complexes to the surface of the silica polyamine composite (SPC), BP-1, which has a poly(allylamine) covalently grafted to the surface of amorphous silica gel, yielded a material that proved to be an effective and novel heterogeneous catalyst for hydroformylation of unsaturated compounds. Surface amino groups of the material were modified with phosphines by covalent and ionic coupling. The modified materials were then treated with Rh(acac)(CO)2 giving the catalysts K-1 and K-2. Catalysts were characterized by solid-state NMR spectroscopy, IR spectroscopy, XPS, TEM, and elemental analysis. The activity and stability of K-1 and K-2 were then studied for the hydroformylation of selected unsaturated compounds. Hydroformylation of terminal double bonds occurred selectively in the presence of internal double bonds. Characterization of the catalysts and the problems encountered with the supported catalysts are discussed. Catalyst K-1 is reusable and can be applied to the hydroformylation

of

linear

olefins,

styrene,

ACS Paragon Plus Environment

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4-vinylcyclohexene, dienes, as well as representative terpenes and other unsaturated hydrocarbons in a batch reactor. INTRODUCION Hydroformylation, also known as the oxo-process is widely used to produce aldehydes or alcohols with 100% atom economy by the addition of hydrogen and carbon monoxide to olefins.1, 2 For this reaction, higher olefins (>C5) are of particular interest in industry because their hydroformylation products are required for the fabrication of plasticizers, solvents or surfactants.3 Metal carbonyl compounds are potential catalysts for hydroformylation, and cobalt or rhodium-based complexes are used industrially in the homogeneous processes. The advantages of the rhodium-catalyzed system are mild reaction conditions, higher n:i (normal to iso) ratios of the products and higher activity.4 However, the recycling of homogeneous catalysts is quite troublesome. Catalyst separation from reaction products and its reuse is one of the most important problems in catalysis. In light of these limitations it is important to consider catalyst systems where the catalyst can be easily separated from the hydroformylation products.5 There are many different methods for separating homogeneous catalysts, which have industrial and scientific importance.6 However, heterogenization of metal complexes is considered to be one of the most promising and interesting approaches.7-10 Besides the advantages of easy of separation and reusability, heterogeneous catalysts can behave differently depending on the surface support properties and catalyst construction. Also, considering economic and ecological aspects, it is preferable to produce catalysts using available and non-toxic materials treated with cheap and efficient reagents. Immobilization of a rhodium complex to a support can provide catalysts for heterogeneous hydroformylation of higher olefins.11 Several solid supports have been developed. These include silica,12,13 silica-coated magnetic particles,14 alumina,15 polymer resins,16 and mesoporous molecular sieves.17-19 A very interesting example has been published recently,20 where phosphorous-containing organic frameworks were synthesized and used as a support. The frameworks included a huge excess of P-ligands for rhodium stabilization. These catalysts showed activity and selectivity comparable to those of homogeneous catalysts, and high stability for reuse, but the production of the P-containing frameworks requires many synthetic steps. Nevertheless, there was no consideration of what the actual form of the active of catalyst is and the possible CO dissociation of the original complexes, with transformation of Rh into the form


2

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of active carbonyls under the reaction conditions, which is necessary when considering the possibility of using heterogeneous catalysts in flow reactors. One of the reviewers suggested that under conditions used for these catalysts would decompose into Rh carbonyls which would act as homogeneous catalysts. In the current work we have investigated this point and taken into account Rh leaching and conversion to soluble carbonyl complexes. We used the silica polyamine composite, BP-1 as a solid support in our study. It is a hybrid material containing inorganic and organic structures, where poly(allylamine) (or poly(ethyleneimine)) chains are anchored on an amorphous silica gel surface. This material combines a high density of functional groups with the rigidity of the silica gel matrix. BP-1 is used in the mining industry for removal of contaminating metals from liquid waste streams and is readily modified with metal selective ligands such aminoacetate (Figure 1).21-22 We used the silica polyamine composite, BP-1 as a solid support in our study. It is a hybrid material containing inorganic and organic structures, where poly(allylamine) chains were anchored on an amorphous silica gel surface. This material combines high density of functional groups and rigidity of silica gel matrix. BP-1 (Figure 1) is used in the mining industry for removal of contaminating metals from liquid waste streams.21-22

Figure 1. Structures of the hybrid materials RESULTS AND DISCUSSION SYNTHESIS


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Modification of BP-1 was performed following two different methods, as shown in Figure 2. In both cases, 4-diphenylphosphinobenzoic acid (4-DPPBA) was used as the modifying reagent. In the first step NH2-groups of BP-1 were treated with 4-DPPBA in the presence of diisopropylcarbodiimide (DIC) as activator in CH2Cl2, yielding the modified support P-1. Next, Rh(acac)(CO)2 was added and after washing and drying catalyst K-1 was produced. In the second method support K-2 was obtained through modification of BP-1 with 4-DPPBA, by ionic coupling where the benzioc acid proton is transferred to the surface amines on BP-1, followed by addition of Rh(acac)(CO)2, washing and drying by similar procedures as for K-1 (Figure 2).

Figure 2. Synthesis of catalysts K-1 and K-2


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Rhodium content in the catalyst samples was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and estimated to be 1.2 and 1.9 % by weight in K-1 and K-2 respectively. The same method was used for determining phosphorus content in the catalyst samples. For the K-1 catalyst the mean value was 0.3% by weight, and for K-2 it was 0.5%. The calculation of the mole ratio P:Rh showed that treating of the modified materials P-1 and P-2 with Rh excess leads to formation of anchored complexes with a P:Rh = 1, in agreement with the proposed structure. CHARACTERIZATION The modified support P-1 and catalyst K-1 were characterized by solid-state CPMAS NMR spectroscopy, infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). In both the proton spectra of P-1 and K-1 samples, there are resonances at δ 1-3 and 5-10, assigned to the aliphatic resonances of the surface amines of BP-1 and the aromatic resonances of the phosphine phenyl groups, respectively (Figure 3a). The 13C NMR spectra, showed characteristic resonances for the carbon atoms in the amide bond fragments at δ 165 confirming covalent coupling to BP-1 (Figure 3b) as well as the expected resonances for the aromatic and aliphatic carbons expected for the composite at δ 130 and 30-40 respectively. The resonance at δ -4 is due to the methyl silanes from the methyltrichlorosilanes used in the synthesis of BP-1. The

31

P

NMR spectra P-1 and K-1 provided insight into the state of the phosphorus on the surface. Modified support P-1 has a P(III) resonance at δ -5.0 and a small amount of a P(V) resonance at δ 28.8. Catalyst K-1 shows a phosphorous resonance at δ 48.5, as well as the disappearance of the resonance at δ -5.0 after reaction of P-1 with Rh(acac)(CO)2, supporting complexation of the Rh to P (Figure 3, c). The resonance at δ 28.8 appears to have increased on conversion of P-1 to K-1 suggesting further oxidation of P(III) to P(V) on reaction with the rhodium complex, but it is not possible to quantify this due to the broadness of the resonances and partial overlap.

Figure 3. Solid-state NMR spectra of P-1 and K-1 samples a) 1H b) 13C c) 31P


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The 1H, 13C and 31P spectra of P-2 and K-2 show the same pattern of resonances as P-1 and K-1, except the absence of signal at 165 ppm in the 13C spectra (Figure 4).

Figure 4. Solid-state NMR spectra of P-2 and K-2 samples a) 1H, b) 13C; c) 31P K-1 and K-2 catalysts were also characterized by IR spectroscopy. Figure 5 shows the change in the spectra as a result of conversion BP-1 to K-1. BP-1 shows only signals at 8001200 cm-1, but in K-1 the IR spectra show signals at 694 cm-1 (Rh-P bond),23 1967 cm-1 (metal carbonyl stretch),17 at 1519-1582 cm-1 (attributable to the acac- fragment) and at 2850-3330 cm-1 (C=C bonds of aromatic fragments). In addition, the spectra show signals attributable to surface adsorbed, protonated acetylacetone at 1704 cm-1 and an NH stretch at 3301 cm-1. The signal at 2115 cm-1 can be attributed to the carbonyl stretch in adsorbed fragments of Rh-C=O resulting from Rh complexation with 4-diphosphinedibenzoic acid.

Figure 5. Infrared spectrum of K-1 run as a solid in ATR mode. The infrared spectra of K-2 shows an almost identical pattern of infrared signals with only minor variations in relative intensity and frequency (Figure 6).


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Figure 6. Infrared spectrum of K-2 run as a solid in ATR mode. The XPS data for K-1 gave additional information about the ligand environment of K-1. From the deconvolution of the experimental spectrum we can identify Rh in the +1 oxidation state, coupled with a phosphine ligand, a carbon monoxide and acetylacetonate (binding energies 308.6 eV for Rh 3d 5/2 and 313,5 eV for Rh 3d 3/2 ).24 Lower intensity peaks contribute to the observed XPS data and are likely due to the presence of other Rh complexes, including bonds between rhodium and nitrogen atoms of the amine polymer, and also with oxygen atoms of acetylacetonate adsorbed on the surface. Adequate interpretation of these data is very difficult because of many types of interaction between Rh atom and the catalyst matrix. Based on the XPS spectra data we concluded that K-1 does not contains Rh(0) nanoparticles or huge inactive clusters but consists predominately of Rh(I) species. Spectra are shown in Figure 7.


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Figure 7. XPS spectra of K-1 TEM analysis of K-1 and K-2 shows no evidence for the formation of inactive Rh/CO huge clusters due to Rh interaction with phosphine ligands (Figure 8).

Figure 8. TEM micrographs of K-1 (a) and K-2 (b) CATALYSIS The hydroformylation of 1-octene was then studied using the K-1 and K-2 catalysts. The mole ratio of olefin/Rh was 800. Table 1 shows a very high yield of aldehyde probably due to the presence of adsorbed Rh complex with 4-DPPBA, not anchored in the process of catalyst synthesis. That can explain 1.6 n/iso ratio in the first catalytic run. After washing under the


8

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reaction conditions the adsorbed complex is active and provides 1-octene hydroformylation with higher selectivity than rhodium carbonyl. After separation of the reaction mixture and washing with toluene the catalyst was still active and is likely present, at least partially, as the phosphine bound Rh(acac)(CO), K-1*. The paragraph at the top of page 9 has been changed and now reads: “After the first run aldehyde yields decrease but remain constant at moderate yields of aldehyde over the next three runs runs with K-1*, demonstrating stability and moderate activity over the subsequent runs 3 runs (2,3,4). Run 5 shows a significant loss in catalyst activity.” The difference between K-1and K-1* is that K-1 consists of surface-bound Rh(P)2(CO)2 species and physically adsorbed (acac)Rh(CO)2. After the first run K-1* the phosphine-bound rhodium complex forms after the initial hydroformylation run or by activation under H2/CO.

Table 1. 1-Octene hydroformylation on K-1 catalyst Reaction mixture composition, %

Run

Octene

Aldehydes

number

conversion, %

yield, %

Octene-1

1

99

93

1

2

99

64

3

98

4

n/iso,

IsoОctane

Aldehydes

aldehydes

4

1

94

1.6

1

33

1

65

1.7

60

1

35

1

62

1.7

98

60

1

36

1

62

1.7

5

22

12

2

42

2

55

1.7

6

15

8

7

40

2

51

1.7

octenes

Conditions: K-1 catalyst – 30 mg, 1-octene – 3.5 mmol, toluene – 2 ml, 5 h, T = 80°C, p (CO/H2 1:1) = 4 MPa Using an average value of 1.5 % by weight of K-1 in the 30 mg catalyst we calculate a TOF of 150 h-1 during the first run and this is probably due to leached rhodium that acts as a homogeneous catalyst. In the subsequent runs TOF range is about 80-100 h-1. To better characterize the catalytic process we compared these results with the homogenous catalyst HRh(CO)3/4, which forms in situ under reaction conditions from Rh(acac)(CO)2 precursor.


9


Under

reaction

conditions

(4.0

MPa

CO/H2,

Page 10 of 23

80°C)

dissociation

of

Rh(acac)(CO)-4-DPPBA complex is possible with production of stable rhodium carbonyls. Therefore, we conducted experiments with this homogeneous analog of K-1 in amounts equivalent to 30 mg K-1 also in amounts equivalent to 1/2 and 1/10 of the Rh contained in 30 mg of K-1. The latter takes into account the possible process of rhodium leaching in the form of free carbonyl complexes, and allowed the estimation of catalyst performance under flow reactor conditions. Table 2 illustrates the results of these comparative experiments. Table 2. Heterogeneous and homogenous catalysts in 1-octene hydroformylation Run, №

Catalyst

In products mixture

Rh content,

Iso-octenes, %

Aldehydes

n/iso

of iso-

mmol

Octene, %

3.0*10-3

1

33

64

1.7

2

2

19

77

0.9

4

3

40

55

1.0

2

3

48

47

1.4

2

(all isomers)

yield, %

Number

aldehydes

K-1*, 30 mg, 1

(Rh - approx. 1% mass)

3.0*10-3

2

3

(the same) Rh(acac)(CO)2

1.5*10-3 (1/2) 0.3*10-3

4

(1/10)

Conditions: catalyst – calculated amount, 1-octene – 3.5 mmol, toluene – 2 ml, 5 h, T = 80°C, p (CO/H2 1:1) = 4.0 MPa The observed data show similar but not identical results for hydroformylation for both catalysts (1-octene conversion, n/iso proportion, number of iso-aldehydes) and equivalent amounts of (10-20%) of rhodium leaching from K-1. It appears, at 4.0 MPa, 80°С dissociation of Rh(acac)(CO), K-1* occurs producing HRh(CO)3/4 which is an active form for isomerization and hydroformylation

catalysts.

Hence,

in

this

system

isomerization

of

1-octene

and

hydroformylation of terminal olefin takes place, the amount of internal isomers of octane increases due to the low velocity of hydroformylation at low catalyst concentration. Higher n/iso ratio observed can be a result of carbonyl complex location at the absorbing layer of the swelling polymer, so, they can be coordinated by N and P atoms contained in the catalyst structure. This decreases terminal bond access in relation to internal ones. The difference between runs 1 and 2


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can be explained by incomplete rhodium leaching from K-1* (10-20%), and Rh carbonyls, as previously mentioned, are stabilized with heteroatoms of the support P-1, this is unlikely when using Rh(acac)(CO)2 in the absence of stabilizing ligands. After cooling and decompression of system, stability of carbonyls dramatically decreases. Therefore, rhodium transforms to the form of heterogeneous complex Rh(acac)(CO), K-1*. Heterogeneous catalysis is confirmed by an additional experiment. To the solution obtained after reaction and isolation from the reaction mixture (after run 1), a fresh portion of 1octene is inserted. Synthesis gas is then compressed to 4.0 MPa and heated up to 80°C for 5 hours with stirring and leads to no conversion of substrate to the products of isomerization and aldehydes, the result of low rhodium in this solution. Multiple reuse of the proposed catalyst is possible, but the character of the catalysis described here is not strictly heterogeneous, which is a considerable disadvantage, limiting the use of such catalysts in flow reactors. We suppose that the previously described catalysts20 can show similar drawbacks, and an excess of anchored phosphine ligands doesn’t provide any guarantee of catalyst stability in flow systems. Nevertheless, by conducting reactions in a batch reactor we estimated recyclability of the catalyst and rhodium losses. Rhodium loss from K-1* catalyst is estimated from ICP AES, to be about 3% after each cycle and accounts for the relatively constant but reduced aldehyde yield. Under these conditions K-1*, results in 1-octene isomerization, to iso-octenes, that accumulate in reaction mixture, 3-octene and 4-octene are not hydroformylated on heterogeneous K-1* in part, because of low velocity of reaction at this concentration of catalyst in active form. However, it must be considered that there are two active rhodium catalysts in this system: homogeneous HRh(CO)3/4 that does most of the hydroformylation and isomerization catalysis, and supported K-1* phosphine-bound rhodium catalyst that has somewhat higher aldehyde L:B selectivity and lower isomerization activity. Even HRh(CO)3/4 has problems hydroformylating internal alkenes under these lower temperature conditions, which will run considerably more slowly than 1- or 2octene. The catalytic behavior of K-1* in hydroformylation depends on catalyst composition and rhodium oxidation state after stabilization in the first catalytic run. We therefore studied the K1* sample with XPS and TEM methods. XPS spectra of K-1* sample were not significantly different compared with the K-1 sample spectra. The most intense peaks have the same binding energies as K-1 (Figure 9). We suggest that the Rh in K-1* is a stable complex in oxidation state


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(+1). The absence of peaks with binding energies 307.0 – 307.4 confirms that K-1* has no stable Rh nanoparticles.

Figure 9. XPS spectra of K-1 (a) in comparison with spectra of K-1* (b) Also TEM images of K-1* confirm the absence of Rh nanoparticles (Figure 10) supporting the proposal that the catalysis performed by a Rh(I) species.


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Figure 10. TEM micrographs of K-1* Kinetic studies of 1-octene hydroformylation show that isomerization is faster than hydroformylation. The accumulated iso-octenes (2-octene) react more slowly, and another part (3-octene and 4-octene) do not react at all. The catalytic activity of K-2 catalyst was investigated by similar procedures. The data in Table 3 show significant activity losses with K-2 in repeated catalytic cycles even after catalyst transformation/stabilization (stable form named K-2*). TOF for the first few cycles are similar to K-1/K-1*, but by cycle 4 aldehyde yields are lower and activity is almost gone by cycle 5. Table 3. Octene-1 hydroformylation on K-2 catalyst Reaction mixture composition, %

Run

Octene

Aldehydes

number

conversion, %

yield, %

Octene-1

1

99

93

1

2

99

61

3

98

4

n/iso,

IsoОctane

Aldehydes

aldehydes

4

1

94

2,7

1

36

1

62

1,6

52

2

44

1

53

1,6

98

43

2

53

1

44

1,5

5

22

2

78

11

1

9

1,3

6

15

˂1

85

9

1

5

1,3

octenes

Conditions: K-2 catalyst – 30 mg, 1-octene – 3,5 mmol, toluene – 2 ml, 5 h, T = 80°C, p (CO/H2 1:1) = 4 MPa The relatively high yield of aldehydes in the first experiment with K-2 is likely caused by adsorbed Rh (in form of complex with 4-diphosphinedibenzoic acid) leaching into the reaction solution and for both covalently bound and ionic-coupled phosphine leads to high catalyst concentration in solution. In the succeeding runs, the reaction was catalyzed with yields similar to other K-1 types of catalysts, but catalyst activity and reaction selectivity was reduced, this is explained by the fact that washing produced no precursor complex after system decompression. The exact nature of the surface bound catalyst is not known at this time but TEM shows no evidence of nanoparticles. The composition of the reaction mixtures was confirmed by GL chromatography, NMR and LC-MS (liquid chromatography – mass spectrometry). As K-1 showed better activity and


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stability in comparison with K-2, it was used (in the form K-1*) for the hydroformylation of selected substrates. The main results are expressed in Tables 4 and 5. Table 4. Hydroformylation of selected olefins with K-1* catalyst Substrate

Aldehydes yield, %

N-aldehyde selectivity, %

1-Hexene

74

64

1-Octene

62

61

1-Decene

60

58

Styrene

95

31

Cyclohexene 4-vinylcyclohexene

No reaction 78

24

Conditions: K-1* catalyst – 30 mg, substrate – 3,5 mmol, toluene – 2 ml, 5 h, T = 80°C, p (CO/H2 1:1) = 4 MPa For linear olefins reaction yield (TOF) decreases slightly with olefin chain lengthening, as is usual for Rh-catalyzed hydroformylation.25 For styrene the iso-aldehyde is the major product, likely due to the expected stabilization of the alkyl intermediate by the phenyl group. Cyclohexene hydroformylation does not occur, and 4-vinylcyclohexene hydroformylated selectively in the vinyl fragment. The n/i ratios observed here are much lower than in related homogeneous systems.25 We then examined the hydroformylation of selected cyclic olefins (Table 4).


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Table 5. Hydroformylation of cyclic olefins and dienes with K-1* catalyst* Reaction mixture composition, % Substrate, index

S

1

2

3

4

5

6

Norbornylene (N)

90

10

-

-

-

-

-

Limonene (L)

53

26

21

-

-

-

-

Eugenol (E)

1

30

25

9

26

9

-

1,7-Octadiene# (O)

1

6

16

5

8

34

12

Conditions: K-1* catalyst – 30 mg, substrate – 3.5 mmol, toluene – 2 ml, 5 h, T = 80°C, p (CO/H2 1:1) = 4 MPa. #Reaction mixture contains 18% of iso-olefins. *Yields for the products refer to the numbered structures in the schemes for a given substrate labeled S. As for cyclohexene norbornylene hydroformylation occurs very slowly giving only 10% conversion to the corresponding aldehyde, N-1 (Figure 11).

Figure 11. Norbornylene hydroformylation on K-1* For limonene hydroformylation (Figure 12) to the corresponding aldehyde L-1 formed in 26% yield and under the reaction conditions the L-2 which can not be hydroformylated even using homogeneous catalysis (Table 5).26 A second possible isomer L-3 is not observed.

Figure 12. Limonene hydroformylation on K-1*


15


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In the case of eugenol, hydroformylation yielded the mixture of aldehydes E-1 – E-3 aldehydes with a total yield of 64% (Table 5, Figure 13) along with the isomerization (E-4) and hydrogenation (E-5) products.

Figure 13. Eugenol hydroformylation on K-1* Complex mixtures of products form in the case of 1,7-octadiene hydroformylation (Table 4, Figure 14).27 The intermediate mono-aldehydes O-1 – O-3 are apparently converted to the di-aldehydes O-4 – O-6 reaction the mixture also contains 18% of isomerized olefins. The total yield of di-aldehydes is 54% with O-5 being the major isomer.

Figure 14. 1,7-octadiene hydroformylation on K-1* Therefore, we have demonstrated here that new heterogeneous catalyst precursor K-1 can be converted to K-1* and used as a hydroformylation catalyst for a range of unsaturated substrates that can be easily separated from reaction mixture and reused again without a regeneration step.


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CONCLUSIONS In this report we developed methods for the synthesis new phosphine-containing hybrid materials based on silica gel containing covalently anchored poly(allylamine) chains (SPC). The phosphine ligand was anchored by covalent and ionic coupling. The materials were characterized by NMR spectroscopy, IR, XPS and TEM. It was shown that phosphorous atoms were initially, mainly in oxidation state +3. On reaction of the surface bound phosphines with the rhodium complex Rh(acac)(CO)2 the formation of a significant amount of P(+5) is formed. Synthesized materials served as Rh-containing catalysts for hydroformylation. The samples contained 1.2-1.9 % by weight Rh. Catalysts were tested in the hydroformylation model reaction of 1-octene. The first catalytic cycle gave high yields of aldehyde (95%) and is likely the result of leaching of the rhodium as HRh(CO)3/4(4-DPPBA) which acted as a homogeneous catalyst. In subsequent cycles the covalent-coupled catalyst derived from K-1 (K-1*) can be reused for several times without significant activity losses, and in 3 runs 1-octene was converted to aldehyde with yields of 5065% and n/iso ratio 1.7. Comparison of the supported catalyst with the homogenous analogue demonstrated possible dissociation of precursor catalytic complex that produces active rhodium carbonyls located in the absorbed layer of the swelling matrix and partially stabilized with heteroatoms incorporated in the matrix structure. After cooling the system, rhodium carbonyls decompose and/or transform into heterogeneous catalysts (perhaps with formation of Rh4 or Rh6 clusters) that allow multiple reuse of the catalyst. The ionic-coupled catalyst, K-2 also shows activity, but loses it during catalyst reuse. These marked drawbacks limit implementation of such catalysts for prospects in industrial application, but studying and understanding of the nature of catalysis will lead to finding solutions in the future. Studies to obtain further structural information on these catalysts and catalytic experiments that will provide additional data are underway in our laboratory.

EXPERIMENTAL MATERIALS 4-vinylcyclohexene, 1-hexene, 1-decene, limonene, 1-nonene, 1,7-octadiene, 1-octene, styrene,

cyclohexene,

eugenol,

norbornylene,

DIC

(diisopropylcarbodiimide)

and

4-

(diphenylphosphino)benzoic acid were obtained from Aldrich and used as received. METHODS


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The products were analyzed using gas-liquid chromatography (GLC) on a «HewlettPackard» and «Crystallux-4000M» chromatographs with a flame ionisation detector. Mass spectra were recorded on an Agilent LC-MS 1100 SL electrospray ionization of the samples (ESI) was used. The analysis was performed in positive ion mode. The voltage at the electrospray needle was 3.5 kV. Drying gas temperature was 250°C, and flow rate was 11 L/min. The structures of catalysts were investigated by X-ray photoelectron spectroscopy with an LAS3000 instrument equipped with a OPX-150 photoelectron retarding-potential analyzer. For photoelectron excitation, aluminum anode radiation (Al Kα = 1486.6 eV) was used at a tube voltage of 12 kV and an emission current 20 mA. Photoelectron peaks were calibrated with reference to the carbon С 1s corresponding to a binding energy of 285 eV. Transmission electron microscopy was performed with an LEO 912 AB OMEGA transmission electron microscope. 1H NMR spectra were recorded on «Varian XL-400» spectrometer at 400 MHz. Solid-state 1H, 13С, 31

P NMR spectra were recorded on Varian NMR Systems spectrometer at the appropriate

resonance frequencies using tan CP pulse sequence for cross polarization and spinning speeds of 10 kHz. Quantitative determination of rhodium in reaction mixtures was performed by ICP AES method using IRIS Interpid II XPL spectometer (Thermo Electron Corp., USA) at the wavelength 343,49 nm. IR-spectra were recorded on «Agilent-8453» spectrometer. SYNTHESIS Preparation of modified supports P-1 and P-2. Modification

of

BP-1

surface

was

conducted

in

an

argon

atmosphere.

4-diphenylphosphinebenzoic acid (0.250 g, 0.817 mmol) was combined with BP-1 (0.300 g, 0.8 mmol

of

NH2-groups)

and

dichloromethane

(2

mL)

in

a

round-bottom

flask.

Diisopropylcarbodiimide (DIC 0.050 mL) was added. The mixture was stirred with a magnetic stirbar for 24 h and then the precipitate was washed with dichloromethane (1х2 ml). The white powder obtained was dried in vacuum. The yield of P-1 was 420 mg (80%). NMR 1Н: δ 1-3 (-СН2-), 5-10 (C6H5-); NMR 13С: δ -4 (SiMe), 20-55 (-СН2-), 110-155 (C6H5-); NMR 31Р: δ -5 (-Р(C6H5-)3). Modified material P-2 was prepared analogously but without adding of DIC and using dichloromethane as solvent. The yield of P-2 was 270 mg (85%). NMR 1Н: δ 1-3 ppm (-СН2-), 5-10 ppm (C6H5-); NMR 13С: δ -4 (SiMe), 20-55 (-СН2-), 110-155. (C6H5-); NMR 31Р: -4.5 ppm (-Р(C6H5-)3). Preparation of catalysts K-1 and K-2


18

Page 19 of 23 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(Acetylacetonato)dicarbonyl rhodium(I) Rh(acac)(CO)2 was synthesized according to published procedures.28 Synthesis of K-1 was conducted in an argon atmosphere. Rh(acac)(CO)2 (0.055 g) was combined with the carrier P-1 (0.255 g) and dichloromethane (2 mL) in a roundbottom flask. The mixture was stirred with a magnetic stir for 12 h and then washed with dichloromethane (3х2 mL). The light-yellow powder obtained was dried in vacuum. The yield of K-1 was 250 mg (78%). NMR 1Н: δ 1-3 (-СН2-), 5-10 (C6H5-); NMR 13С: δ165,6 (-C(=O)-NH-) along with expected resonances for P-1; NMR

31

Р: δ 48.8 (Rh-Р-), 28.5(P=O). In the IR-

spectrum there were bands at 694 cm-1 (Rh-P-), 1704 (acacH), 1635-1652 (acac-), 1967 (RhC=O), 2850 – 3330 (C6H5-), 1400-1500 cm-1 (-СН=СН-). Synthesis of K-2 catalyst was conducted analogously (using carrier P-2 instead of P-1). The yield was 265 mg (82%). NMR 1Н: δ 1-3 (-СН2-), 8-10 (C6H5-); NMR 13С: δ 20-55 (-СН2-), 110-155 (C6H5-); NMR

31

Р: δ 50 (Rh-Р-), 30 (P=O). Bands in the IR-spectrum are at

694 (Rh-P-), 1708 (acacH), 1635-1652 (acac-), 1967 (Rh-C=O), 2850 – 3330 (C6H5-), 1400-1500 cm-1 (-СН=СН-). The catalysts K-1 and K-2 were characterized by ICP AES method. The content of rhodium was founded as 1.2 and 1.9% respectively. Catalytic testing procedure The reaction was carried out in a steel reactor equipped with a stirbar at 80°C under a 4.0 MPa (СO/H2=1:1) pressure. The stir bar, the catalyst, substrate and toluene were introduced into the reactor. Then, the reactor was sealed and pressurized with СO/H2 at the demanded pressure. The mixture was stirred at 80°C and after the reaction was finished, the reactor was cooled down and depressurized. The solution was carefully separated from the catalyst and analyzed by GLC and GC-MS. ACKNOWLEDGEMENT We gratefully acknowledge the support of the Russian Federation Basic Research Agency (RFBR), research project No. 17-03-00464 a.

We also acknowledge the helpful

comments of one of the reviewers that significantly improved the manuscript.

REFERENCES (1) Hebrard, F.; Kalck, P. Cobalt-Catalyzed Hydroformylation of Alkenes: Generation and Recycling of the Carbonyl Species, And Catalytic Cycle. Chem. Rev. 2012, 109, 4272–4282.


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(2) Franke, R.; Selent D.; Borner A. Applied Hydroformylation. Chem. Rev. 2012, 112, 5675– 5732. (3) Van Leeuwen, P. W. N. M. Homogeneous Catalysis. Understanding the Art Kluwer Academic Publ.: Dordrecht, 2004. (4) Van Leeuwen, P. W. N. M.; Claver C. Rhodium-Catalyzed Hydroformylation Kluwer Academic: Dordrecht, 2000. (5) Collis, A. E. C.; Horvath I. T. Heterogenization of Homogeneous Catalytic Systems Catal. Sci. Technol. 2011, 1, 912–919. (6) Gorbunov, D. N.; Volkov, A. V.; Kardasheva, Yu. S.; Maksimov, A. L.; Karakhanov, E. A. Hydroformylation in Petroleum Chemistry And Organic Synthesis: Implementation of the Process and Solving the Problem Of Recycling Homogeneous Catalysts (Review) Petrol. Chem. 2016, 55, 8, 587–603. (7) Copéret, C.; Chabanas, M.; Petroff Saint‐Arroman, R.; Basset J. M. Homogeneous And Heterogeneous Catalysis: Bridging the Gap Through Surface Organometallic Chemistry Angew. Chem. Int. Ed. 2003, 42, №2, 156-181. (8) Udayakumar, V.; Alexander, S.; Gayathri, V.; Shivakumaraiah; Patil, K. R.; Viswanathan, B. Polymer-Supported Palladium-Imidazole Complex Catalyst for Hydrogenation of Substituted Benzylideneanilines J. Mol. Cat. A: Chem. 2010, 317, 111-117. (9) Swennenhuis, B. H. G.; Chen, R.; Van Leeuwen P. W. N. M.; De Vries, J. G.; Kamer, P. C. J. Supported Chiral Monodentate Ligands in Rhodium-Catalysed Asymmetric Hydrogenation and Palladium-Catalysed Asymmetric Allylic Alkylation Eur. J. Org. Chem. 2009, 33, 5796-5803. (10) Goni, M. A.; Rosenberg, E.; Meregude, S.; Abbott, G. A. Methods Study of Immobilization of PONOP Pincer Transition Metal Complexes on Silica Polyamine Composites (SPC) J. Organometal. Chem. 2016, 807, 1-10. (13) Haumann, M.; Dentler, K.; Joni, J.; Riisager, A.; Wasserscheida, P. Continuous Gas-Phase Hydroformylation of 1-Butene Using Supported Ionic Liquid Phase (SILP) Catalysts Adv. Synth. Catal. 2007, 349, 425–431. (14) Abu-Reziq, R.; Alper, H.; Wang, D.; Post, M. L. Metal Supported on Dendronized Magnetic Nanoparticles: Highly Selective Hydroformylation Catalysts J. Am. Chem. Soc. 2006, 128, 5279–5282.


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(15) Li, P.; Thitsartarn, W.; Kawi, S. Highly Active And Selective Nanoalumina-Supported Wilkinson’s Catalysts for Hydroformylation of Styrene Ind. Eng. Chem. Res. 2009, 48, 1824– 1830. (16) Fujita, S.; Akihara, S.; Fujisawa, S.; Arai, M. Hydroformylation of 1-Hexene Using Polymer-Supported Rhodium Catalysts in Supercritical Carbon Dioxide J. Mol. Catal. A: Chem. 2007, 268, 244-250. (17) Peng, Q.; Yang, Y.; Yuan, Y. Immobilization of Rhodium Complexes Ligated with Triphenyphosphine Analogs on Amino-Functionalized MCM-41 and MCM-48 for 1-Hexene Hydroformylation J. Mol. Catal. A: Chem. 2004, 219, 175–181. (18) Huang, L.; Ye, H.; Kawi, S. Catalytic Studies of Aminated MCM-41-Tethered Rhodium Complexes for 1-Hexene Hydroformylation Appl. Catal. A: Gen. 2004, 265, 247–257. (19) Li, P.; Kawi, S. Dendritic SBA-15 Supported Wilkinson's Catalyst for Hydroformylation of Styrene Catal. Today. 2008, 131, 61–69. (20) Sun, Q.; Dai, Z.; Liu,X.; Sheng, N.; Deng, F.; Meng, X.; Xiao, F.-S. Highly Efficient Heterogeneous Hydroformylation over Rh-Metalated Porous Organic Polymers: Synergistic Effect of High Ligand Concentration and Flexible Framework J. Am. Chem. Soc. 2015, 137, 5204–5209. (21) Rosenberg, E.; Pang, D. C. System for Extracting Soluble Heavy Metals from Liquid Solutions U. S. Patent 5997748, 1999. (22) Allen, J.; Rosenberg, E.; Karakhanov, E.; Kardashev, S. V.; Maximov, A.; Zolotukhina A. Catalytic Properties of Transition Metal Salts Immobilized on Nanoporous Silica Polyamine Composites II: Hydrogenation Appl. Organomet. Chem. 2011, 4, 245-254. (23) Mukhopadhyay, K., Mandale, A. B., Chaudhari, R. V. Encapsulated HRh(CO)(PPh3)3 in Microporous and Mesoporous Supports: Novel Heterogeneous Catalysts for Hydroformylation Chem. Mater. 2003, 15, 1766-1777. (24) Standfest-Hauser, C. M.; Lummerstorfer, T.; Schmid, R.; Hoffmann, H.; Kirchner, K.; Puchberger, M.; Trzeciak, A. M.; Mieczyńska, E.; Tylus, W.; Ziółkowski, J.J. Rhodium Phosphine

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(25) Sharma, S. K.; Parikh, P. A.; Jasra, R. V. Hydroformylation Of Alkenes Using Heterogeneous Catalyst Prepared by Intercalation of HRh(CO)(TPPTS)3 Complex In Hydrotalcite J. Mol. Catal. A: Chem. 2010, 316, 153-162. (26) Baricelli, P. J., Melean, L. G., Rodríguez, M., Santos, M., Rosales, M. Escalante, E. Biphasic Hydrogenation and Hydroformylation of Natural Olefins with a Binuclear Rhodium Complex In Ionic Liquid/Toluene J. Chem. Chem. Eng. 2013, 7, 299-305. (27) Alsalahi, W.; Trzeciak, A. M. Comparison of “On Water” and Solventless Procedures in the Rhodium-Catalyzed Hydroformylation of Diolefins, Alkynes, and Unsaturated Alcohols J. Mol. Catal. A: Chem. 2016, 423, 41-48. (28) Varshavsky, Yu. S.; Cherkasova, T. G. A Simple Method for Preparation of Acetylacetonatedicarbonyl Rhodium (I) Russ. J. of Inorg. Chem. 1967, 12, 1709-1712.


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O P

Rh

Rh

O

O

O

O O

P

Rh

Rh

O P

P CO HN

O H 2N HN

HN

NH2

H2N HN CH3 CH3 O Si O Si O Si O Si O O O O O Si O Si O Si O Si SiO SiO 22 H 2N

catalyst K-1

CO

CO

O

+H

3N

-O

O H 2N HN

O

O acac-

CO

O +H

O_ 3N

NH2

H2N HN CH3 CH3 O Si O Si O Si O Si O O O O O Si O Si O Si O Si SiO SiO 22 H 2N

Catalyst K-2


O

New heterogeneous Rh-containing catalysts immobilized on a hybrid

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