KR20190059113A - Zirconium-Polysilsesquioxane Nano composites as Catalyst for Transfer Hydrogenation - Google Patents

Abstract

The present invention relates to: a nanocomposite, in which a Zr-containing nanoparticle having a structure of Zr-O-Zr, Zr-OH-Zr, or both and polysilsesquioxane having a nanocage structure are combined; and to a catalyst for transfer hydrogenation comprising the nanocomposite. The catalyst comprising the nanocomposite of the present invention exhibits excellent performance in transfer hydrogenation at low temperatures and is useful for biorefinery and organic synthesis.

Description

Zirconium-polysilsesquioxane nanocomposites (Zirconium-Polysilsesquioxane Nano-composites as Catalyst for Transfer Hydrogenation)

More particularly, the present invention relates to a catalyst for transfer hydrogenation comprising a zirconium-polysilsesquioxane-based nanocomposite, and more particularly, to a catalyst for transfer hydrogenation using Zr-O-Zr or Zr-OH- Containing Zr-containing nanoparticles; And a polysacsesquioxane-bonded nanocomposite having a nanocage structure, and a catalyst containing the nanocomposite.

Developing catalysts and processes that produce a wide range of platforms and value-added chemicals from natural, abundant and lignocellulosic biomass is an environmentally friendly alternative to chemicals and chemical fuels produced from fossil raw materials such as petroleum And is a promising new technology to create a sustainable society. Among them, a process for economically producing levulinic acid (LA) from woody biomass is being developed, and levulinic acid can be converted into a useful compound GVL (γ-Valerolactone, valerolactone). GVL is recognized as a versatile building block in that it can be used as an additive for liquid fuels in transport, as a precursor for the production of polymeric monomers, and for a variety of value added chemistries including organic solvents and bio-oxygenates Can be used as precursors for the synthesis of materials. GVL itself has low melting point and high boiling point; Very low vapor pressure, even at high temperatures; And excellent chemical and physical properties such as immediate miscibiling with water without formation of an azeotropic mixture, it is excellent as a green solvent for biomass treatment.

Generally, three major strategies have been developed for the production of GVL from the esters of levulic acid (LA) and LA, depending on the diversity of the hydrogen source. The hydrogen molecule (H ₂ ) is the most common hydrogen source used in this reaction, and the reaction occurs in the presence of various metal catalysts (eg, Ru, Pt, Pd, Ni, Co, Cu). In addition, formic acid (FA) is formed at the same molar amount as LA during acid hydrolysis of carbohydrates, and is also used as a hydrogen source to produce GVL from LA to implement the principle of atom economy . Catalyst systems comprising nickel-promoted copper-silica and Ag-Ni-ZrO ₂ nanocomposites have been successful in converting LA to the same molar amount of GVL, consuming the same molar amount of FA as a hydrogen peroxide (Green Chem. 2011, 13, 1755). However, the two hydrogenation strategies described above are limited in volume production due to some limitations (e.g., harsh reaction conditions, use of corrosive acids, use of precious metals and non-environmentally friendly solvents) (Green Chem., 2015 , 17, 1626).

Recently, Dumesic et al. For the first time proposed a catalyst based on the Meerwein-Ponndorf-Verley (MPV) reduction reaction principle in which a hydrogen secondary alcohol is used as a hydrogenation catalyst and LA and alkyl levorites are hydrogenated with GVL under non- (Chem. Commun., 2011, 47, 12233). Here, we have demonstrated that ZrO ₂ has better activity than other metal oxides due to its amphoteric nature. The chemical selectivity of the MPV reduction reaction of aldehydes and ketones to carbonyl groups, the replacement of hydrogen molecules with alcohols, and the effective performance of non-noble metal-containing catalysts provide a cost-effective alternative to GVL manufacture. Thus, in recent years, various zirconium-based catalyst systems such as ZrO ₂ , ZrO (OH) ₂ and amorphous Zr-complexes (zirconium 4-hydroxybenzoate (Zr-HBA), zirconium phosphonate It has been reported for the above reaction. For example, in the literature [RSC Adv., 2014, 4, 13481], the use of a crystalline porous material with an appropriate surface area (Zr-beta zeolite, 474 m ² / g) Catalyst systems for conversion to GVL are described. However, the above-mentioned technique has a very low active site with a Zr content of 10% or less in Zr-beta zeolite, and the catalyst production method is complicated and time consuming, so there is a limitation in commercialization.

Silsesquioxane is a metal silicon oxide having a cage structure and is a nano-porous body having a flexible structure. Such properties make it possible to be usefully applied in various fields such as medical devices, coating agents, adhesives, adsorbents, lubricants and catalysts. POSS (Polycytahedral oligomeric silsesquioxanes) have structural characteristics of nano cage. The functional aspects available in cage structures allow POSS molecules to have vigorous chemical reactions and compatibility with various polymers. Moreover, the small particle size of POSS (1-3 nm) allows for good dispersion at the molecular level. In addition, a bulky POSS molecule has a lot of free space in the molecule, and gas molecules can pass through it. In addition, when POSS molecules bind to other polymers to form POSS-containing hybrid polymers, they have unique properties compared to when polymers bind to other inorganic molecules.

First, most nanoscale inorganic molecules are not well soluble in hybrid polymers because of their non-uniform size, while POSS is well dispersed in the molecular scale and is therefore well soluble in hybrid polymers. Secondly, nanoscale inorganic molecules have difficulty in defining the functional groups of the molecules, and they are not only difficult to accurately locate, but also difficult to count. However, in the case of POSS, since the functional groups are present at each corner like TSP POSS (Trisilanol-phenyl-POSS), positioning and number counting are easy. For example, TSP POSS has a cage structure of T8, and a total of seven Si edges and a phenyl group are connected to each corner. One side has three openings, And can be combined with other transition metals or noble metal catalyst components to be used in the production of nano metal complexes.

The present invention provides a catalyst for a mobile hydrogenation reaction capable of operating at a low temperature of 200 ° C or lower.

The present invention also provides a catalyst for the production of gamma-valerolactone or furfural alcohol which is environmentally friendly and capable of mass production under mild reaction conditions.

A first aspect of the present invention is a Zr-containing nanoparticle having a structure of Zr-O-Zr, Zr-OH-Zr or both; And a polysacsesquioxane-bonded nanocomposite having a nanocage structure.

A second aspect of the present invention provides a catalyst for transfer hydrogenation comprising the nanocomposite of the first aspect.

A third aspect of the present invention provides a process for preparing gamma-valerolactone through the mobile hydrogenation of ethyl levulinate (EL) using the catalyst of the second aspect.

A fourth aspect of the present invention provides a method of producing a furfural alcohol through a mobile hydrogenation reaction of furfural using the catalyst of the second aspect.

Hereinafter, the present invention will be described in detail.

In the present invention, a polyhedral oligomeric silsesquioxanes (POSS) nanocage refers to polysacsesquioxane having a nanocage structure, or " cage structure ".

In the present invention, a nano composite is a composite material composed of a dispersed phase of a nanometer scale and a matrix, which is composed of two or more kinds of structures or materials and has a phase size of nanometers (10 ^-9 m ). ≪ / RTI > More specifically, in the present invention, the nanocomposite may be a Zr-containing nanoparticle having a structure of Zr-O-Zr, Zr-OH-Zr or both; And nanosized nanosized nanocomposites having a nanocage structure.

In the present invention, Polyhedral Oligomeric Silsesquioxanes (POSS) have a structural characteristic of " RxTx " nano cage. Where R represents an "organic functional group", T represents a "silsesquioxane" linkage structure, "SiO _3/2 ", and x represents the number of "silsesquioxanes" connected in the cage.

The present invention relates to a process for preparing a nanocomposite comprising a polysacceptoquinoxane having a nanocage structure represented by the following general formula (1) or (2) and a Zr-containing nanoparticle having a structure of Zr-O-Zr or Zr- And is used as a catalyst for hydrogenation reaction (transfer hydrogenation).

[Chemical Formula 1]

R ₈ Si ₈ O ₁₂

In Formula 1, R is selected from the group consisting of linear alkyl having 1 to 20 carbon atoms, branched alkyl, aromatic alkyl, alicyclic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, Functional groups such as alkylammonium, polyethylene glycol, dialkylsilane, diol alkyl, alkyldicarboxylate, fluoroalkyl, chloroalkyl, alkylmaleamide, cyanoalkyl, norbomylalkyl, allylalkyl, vinylalkyl, to be. Preferably, R is a linear alkyl having 1 to 13 carbon atoms, branched alkyl, aromatic alkyl, alicyclic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, polyethylene glycol, di Alkylsilane, diol alkyl, alkyldicarboxylate, fluoroalkyl, chloroalkyl, alkylmaleimide, cyanoalkyl, norbornylalkyl, allylalkyl, vinylalkyl, mercaptanalkyl and the like. More preferably, R is selected from linear alkyl of 1 to 10 carbon atoms, branched alkyl, aromatic alkyl, cycloaliphatic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, polyethylene glycol, Diol alkyl, alkyl dicarboxylate, fluoroalkyl, cyanoalkyl, norbornylalkyl, allylalkyl, vinylalkyl, and the like.

The polysilsesquioxane of Formula 1 has a completely closed " R ₈ T ₈ POSS nano-octaque structure " as shown in Fig.

(2)

R ₇ Si ₇ O ₈ (OH) ₃

In Formula 2, R is a linear alkyl group having 1 to 20 carbon atoms, branched alkyl, aromatic alkyl, alicyclic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, Functional groups such as alkylammonium, polyethylene glycol, dialkylsilane, diol alkyl, alkyldicarboxylate, fluoroalkyl, chloroalkyl, alkylmaleamide, cyanoalkyl, norbomylalkyl, allylalkyl, vinylalkyl, to be. Preferably, R is a linear alkyl having 1 to 13 carbon atoms, branched alkyl, aromatic alkyl, alicyclic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, polyethylene glycol, di Alkylsilane, diol alkyl, alkyldicarboxylate, fluoroalkyl, chloroalkyl, alkylmaleimide, cyanoalkyl, norbornylalkyl, allylalkyl, vinylalkyl, mercaptanalkyl and the like. More preferably, R is selected from linear alkyl of 1 to 10 carbon atoms, branched alkyl, aromatic alkyl, cycloaliphatic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, polyethylene glycol, Diol alkyl, alkyl dicarboxylate, fluoroalkyl, cyanoalkyl, norbornylalkyl, allylalkyl, vinylalkyl, and the like.

The polysilsesquioxane of Formula 2 has an "incomplete R ₈ T ₈ POSS nano-octa cage" structure with a part of the cage structure open as shown in FIG.

The nanocomposite of the present invention may be formed by bonding Zr-O-Zr, Zr-OH-Zr or both of Zr-containing nanoparticles to a functional group linked to polysilsesquioxane having a nanocage structure.

Although the structure of the POSS nanocage is the same, the nanocomposite properties and catalytic activity of the POSS nanocage and zirconium-containing nanoparticles are affected by the crystal structure, functional groups (R number and chemical and physical structural characteristics) of the POSS nanocage, , It is difficult to predict which nanocomposite of POSS nanocage and zirconium-containing nanoparticles will excellently perform their functions under specific catalytic reaction conditions.

The present inventors have experimentally designed various angles and found that the crystal structure of POSS nanocage, the number of functional groups (R number and chemical and physical structural characteristics), and the bonding method with zirconium-containing nanoparticles and conditions (POS) nanocage with R ₈ Si ₈ O ₁₂ and R ₇ Si ₇ O ₈ (OH) ₃ structure and Zr-O-Zr , Transfer hydrogenation of ethyl levulinate (EL) to gamma-valerolactone (GVL) in the presence of nanocomposites of zirconium-containing nanoparticles having the structure of Zr-OH-Zr or both Catalyzed hydrogenation of furfural to furfuryl alcohol; Transfer hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL); Transfer hydrogenation of furfural to 2-methylfuran (2-MF); Transfer hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran (DMF); Transfer hydrogenation of glycerol to 1,2-propanediol (1,2-PDO); Transfer hydrogenation of fructose to 5-hydroxymethylfurfural (HMF); Transfer hydrogenation of glucose to gamma-valerolactone (GVL); Transfer hydrogenation of fructose to gamma-valerolactone (GVL); Transfer hydrogenation of butyl levulinate (BL) to gamma-valerolactone (GVL); Transfer hydrogenation of glycerol to 1,2-propanediol (1,2-PDO); (1-hydroxyethyl) benzene (1-HB) to ethylbenzene; Or to a mobile hydrogenation reaction of 5-hydroxymethyl furfural (HMF) to 1,6-hexanediol (HDL). The present invention is based on this.

Oxide and hydroxide catalysts such as ZrO ₂ and Zr (OH) ₄ were used for conventional MPV (Meerwein-Ponndorf-Verley) reaction or catalytic transfer hydrogenation (CTH). However, since the surface area is low, and the active sites of Zr-O-Zr and Zr-OH-Zr are continuous, the reactants approach the adjacent Zr active sites continuously so that the reaction is very close to the distance and the hydrophilic property is strong. There is a problem in that the conversion and the selectivity of the reaction are low due to obstacles to the approach and diffusion of the product. To solve these problems, the present inventors have found that by combining Zr and POSS nanocages having various organic functional groups, a variety of POSS nanocages and Zr-O- Zr, Zr-OH-Zr, or a zirconium-containing nanoparticle having both of these structures. Furthermore, POSS nano-cage, Zr-O-Zr and Zr-OH-Zr, which have R ₈ Si ₈ O ₁₂ and R ₇ Si ₇ O ₈ (OH) ₃ structures among many POSS nanocages and zirconium- Zirconium-containing nanoparticles having a zirconium-containing structure and zirconium-containing nanoparticles have a very wide surface area, and zirconium is stabilized and organic functionalized by POSS nanocage, so that the reactivity per unit active site is increased. High.

The nanocomposite of the POSS nanocage and the zirconium-containing nanoparticles according to the present invention has a higher surface area and permanent porosity from the viewpoint of the catalyst, so that the reactant is accessible compared to a simple nano-zirconium catalyst and the active site is provided with a larger number of active sites can do. In addition, diffusion of reactants and products can be facilitated along with the various functional groups (R-) of the cage to enhance the interaction of the active sites present in the reactants and the porous nanocomposites. Therefore, when the nanocomposite according to the present invention is used as a catalyst, the conversion and selectivity of the mobile hydrogenation reaction can be increased, which is highly desirable from the standpoint of green chemistry.

Compared to zeolites, POSS nanocages have relatively low stability and thermal stability to hydrolysis of organic functional groups. However, due to the high chemical, thermal and mechanical stability of zirconium, the POSS nanocage and zirconium- Have relatively high moisture and thermal stability.

In the present invention, the weight ratio of polysilsesquioxane to zirconium-containing nanoparticles may be 100: 0.01-10, preferably 100: 0.1-5. When the weight ratio of polysilsesquioxane to the zirconium-containing nanoparticles is less than 100: 0.01, the content of the POSS nanocage is too small, so that the function of the POSS nanocage does not work and there is no improvement in activity and selectivity. When the weight ratio of polysilsesquioxane exceeds 100: 10, there is a problem that the POSS nanocage reacts excessively with zirconium-containing nanoparticles as an active ingredient to reduce active sites, resulting in decreased activity.

The CTH reaction at low temperature is reported in the Raney Ni catalyst. However, there is a problem that it is necessary to use caution for practical use because it is spontaneously ignited when exposed to air. However, when the nanocomposite of the POSS nanocage and zirconium-containing nanoparticles according to the present invention is used as a catalyst, the moving hydrogenation reaction of ethyl levulinate (EL) can be performed even in an open system.

The present inventors have found that a POSS nanocage having a series of R ₈ Si ₈ O ₁₂ and R ₇ Si ₇ O ₈ (OH) ₃ structures and zirconium-containing nanoparticles having a structure of Zr-O-Zr, Zr-OH- Were synthesized and used as a catalyst to test the CTH reaction using hydrogen - free isopropanol and bio - alcohols, and EL was subjected to MPV reduction.

The inventors have found through experimentation that large surface area, large pore size and well-balanced acid-base characteristics or functional cage functionalization of active metal clusters are important factors for the selective conversion of EL to GVL.

The POSS nanocage having the structure of R ₈ Si ₈ O ₁₂ and R ₇ Si ₇ O ₈ (OH) ₃ according to the present invention and the zirconium-containing POSS nanocage having the structure of Zr-O-Zr or Zr-OH- The nanocomposite nanoparticles showed excellent chemical stability and catalytic activity even at low temperatures (below 200 ℃).

Since the catalyst comprising the nanocomposite of the present invention is a catalyst compounded with a nanocage structure having crystallinity, the inorganic building block (Zr particles, Zr (OH) ₄ clusters), which is a catalytically active component, The reactivity of the reactant is higher than that of ZrO ₂ even at a relatively low temperature because the reactivity of the reactant is increased due to the enhancement of lipophilic adsorption property and structural stability.

Thus, the catalyst comprising the nanocomposite of the present invention can be used as an excellent potential catalyst in a low temperature reaction for biorefinery.

The size of the nanocomposite of the present invention may be 5 to 200 nm, preferably 10 to 100 nm. When the size of the nanocomposite exceeds 200 nm, there is a limitation in the diffusion rate of the reactants and the product due to the decrease of the surface area and the pore volume with the increase of the crystal size, .

In one embodiment, a POSS nanocage having R ₈ Si ₈ O ₁₂ and R ₇ Si ₇ O ₈ (OH) ₃ structures and zirconium-containing nanoparticles having a structure of Zr-O-Zr, Zr-OH- Coupled nanocomposites provide more active sites because they have a larger surface area than simple nanosized zirconiums and have greater pore volume, making them more accessible to active sites.

Simple Zr-containing nanoparticles have acidic and base sites within the structure. Acid-base sites are derived from Zr-O-Zr or Zr-OH-Zr bonds present in Zr metal clusters. The acid and base (Zr ⁴⁺ and O ^2- ) sites of the metal cluster cooperate to interact with both EL and isopropanol to form a six-membered ring transition state. Zirconium metals that develop acid-base properties of Zr are considered active sites in the selective formation of EL to GVL. However, in the case of a simple nano-zirconium catalyst, since the active sites of Zr-O-Zr and Zr-OH-Zr are continuous, the activity may be low due to the proximity of the reactants to the adjacent Zr active sites. On the other hand, the zirconium-polysilsesquioxane complex of the present invention is a Zr-containing zirconium-polysilsesquioxane complex having Zr-O-Zr, Zr-OH-Zr or both; And polysilsesquioxane having a nanocage structure are bonded to each other to enhance the stability of the long-term reaction of the catalyst by increasing the stability of various nanocomposite hybrids and nanodispersions.

The catalyst comprising the nanocomposite of the present invention is not only excellent as a catalyst for transfer hydrogenation of ethyl levulinate (EL) to gamma-valerolactone (GVL) under mild conditions, transfer hydrogenation of furfural to furfuryl alcohol; Transfer hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL); Transfer hydrogenation of furfural to 2-methylfuran (2-MF); Transfer hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran (DMF); Transfer hydrogenation of glycerol to 1,2-propanediol (1,2-PDO); Transfer hydrogenation of fructose to 5-hydroxymethylfurfural (HMF); Transfer hydrogenation of glucose to gamma-valerolactone (GVL); Transfer hydrogenation of fructose to gamma-valerolactone (GVL); Transfer hydrogenation of butyl levulinate (BL) to gamma-valerolactone (GVL); Transfer hydrogenation of glycerol to 1,2-propanediol (1,2-PDO); (1-hydroxyethyl) benzene (1-HB) to ethylbenzene; Or a transfer hydrogenation reaction of 5-hydroxymethyl furfural (HMF) to 1,6-hexanediol (HDL).

When the catalyst according to the present invention is used, a hydrogen donor may be used in the presence of isopropanol, alcohols such as methanol, ethanol, glycerol and butanol, cyclic ethers, benzyl alcohol, cyclohexanone, 2-propanol, ethylene glycol, Hydrogen indole, 1,2,3,4-tetrahydroquinoline, cyclohexene, cyclohexane diene, limonene, hydrazine, ammonium formate, ammonium hypophosphite or a mixture thereof can be used, but isopropanol is preferably used . Isopropanol is an excellent hydrogenation alcohol because of its low reducing potential.

It is preferable to use ethyl levulinate (EL) rather than levulic acid (LA) when using the catalyst according to the present invention for GVL production. This is because the ethanolysis of carbohydrates provides high yields, which makes it easier to separate products from carbohydrates because of their higher volatility compared to LA, and because of the free form of acid, there is no safety and economical concern for reactor corrosion

The catalyst of the present invention includes a nanocomposite formed by bonding Zr-O-Zr, Zr-OH-Zr or Zr-containing nanoparticle zirconium having both structures to a functional group connected to polysilsesquioxane having a nanocage structure , Can be reused at least 5 times without loss of catalytic activity under certain reaction conditions.

According to the present invention, POSS nanocage having R ₈ Si ₈ O ₁₂ and R ₇ Si ₇ O ₈ (OH) ₃ structure and zirconium-containing nanoparticles having a structure of Zr-O-Zr, Zr-OH- When a mobile hydrogenation reaction is carried out at a low temperature of from room temperature to 250 ° C, preferably 200 ° C or less, more preferably 80 ° C to 160 ° C, using a bonded nanocomposite as a catalyst, various kinds of hydrogenation products such as ethyl levulinate The conversion rate of the substrate can be above 90% (see Table 3). In addition, the hydrogenation reaction can be performed at a low temperature of 50 占 폚 to increase the selectivity of the reactants of the alcohol (see Table 2).

The catalyst comprising the nanocomposite according to the present invention exhibits excellent performance in a mobile hydrogenation reaction at a low temperature and is useful for biorefinery and organic synthesis.

1 is a representative structural view of R ₈ Si ₈ O ₁₂ (complete R ₈ T ₈ based POSS nano-octaque cage).
2 is a representative structural view of R ₇ Si ₇ O ₈ (OH) ₃ (incomplete R ₈ T ₈ POSS nano-octaque cage).
Fig. 3 (A) is a graph showing the results of dispersing zirconium-containing nanoparticles in a hexane-water layer as a result of the hydrophilic nature of the particles; (B) shows that the nanocomposite of the POSS nanocage and the zirconium-containing nanoparticle according to the present invention is dispersed in the hexane-water layer, and as a result, the lipophilic property of the particles indicates that the upper hexane layer contains white particles.
4 is a SEM photograph of a nanocomposite of a POSS nanocage and a zirconium-containing nanoparticle according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. These embodiments are only for describing the present invention more specifically, and the scope of the present invention is not limited by these examples.

Chemicals and materials

Ethyl LES disadvantage carbonate (Ethyl levulinate, 99%), gamma-valerolactone (γ-valerolactone, 99%), 2- propanol (99.5%), naphthalene _{(98%), ZrOCl 2 .8H} 2 O (98%) , Acetonitrile (99.5%), sulfuric acid (H ₂ SO ₄ , 95%) and nitric acid (99.5%), sodium hydroxide (NaOH, 98%), hexane (95%), tetrahydrofuran HNO ₃ , 60%) were purchased from Samchun Pure Chemicals, Korea. Trisilanol Phenyl POSS 99.9% and N-Phenylaminopropyl POSS 99.9% were purchased from Hybrid Plastics Inc., Hattiesburg, Respectively. All chemicals were used without further purification.

Production Example 1: Synthesis of nano-zirconium

ZrOCl ₂ aqueous solution was prepared by mixing 392.25 g of ZrOCl ₂揃 8H ₂ O (1.217 mol), 57.45 g of 97 wt% H ₂ SO ₄ (0.585 mol), and 369.35 g of H ₂ O (20.52 mol). The ZrOCl ₂ aqueous solution and the 10 wt% aqueous NaOH solution were stored in bottles and then cooled to 5 ° C in a refrigerator. 200 g of distilled water was placed in a 5 L double jacketed glass reactor and cooled to -1 ° C. The ZrOCl ₂ aqueous solution and the 10 wt% NaOH aqueous solution cooled in the refrigerator were each immersed in an ice bath. The two solutions were added to the double jacketed glass reactor at a rate of 20 ml / min using a pump. At this time, the temperature inside the solution was maintained at 10 캜 or lower, and the pH was adjusted to 8. The solution was stirred for 1 to 10 minutes using a blender. The agitated solution was again added to a 4 L beaker and the pH was adjusted to 13 by adding a 28 wt% aqueous solution of NaOH at a rate of 20 ml / min. The precipitated zirconium cake was centrifuged at 8000 rpm for 3 minutes to wash the zirconium cake 5 times. After the distilled water was poured into the slurry state, a 30 wt% HNO ₃ aqueous solution was added at a rate of 10 ml / min to adjust the pH to 8. The solution was centrifuged and washed twice. The distilled water was poured into a 4 L solution and hydrothermally synthesized at 130 ° C. for 5 hours using an autoclave apparatus. The hydrothermally synthesized solution was filtered to remove water and then washed with ethanol. 300 ml of distilled water and 450 ml of ethanol were added to the zirconium cake, followed by ball milling for 20 hours. The zirconium dispersion obtained by ball milling was filtered to obtain a zirconium cake, followed by drying and pulverization at 100 DEG C to obtain zirconium-containing nanoparticles (nano-Zr) in powder form.

Example 1: Preparation of nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: N-phenylaminopropyl) Composite synthesis

nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: N-phenylaminopropyl) complex was synthesized by the reflux method.

Specifically, 50 g of tetrahydrofuran and 200 g of acetonitrile were added to a 500 ml round-bottomed flask equipped with a condenser, and then 50 g of nano-zirconium (nano-Zr) synthesized in Production Example 1 and 10 wt% N-phenylaminopropyl POSS (Hybrid Plastics Inc. USA) 4 g of the solution was added and reacted at 80 DEG C for 24 hours with stirring. After the completion of the reaction, the mixture was maintained at 40 ° C for 20 hours, and 0.5 mL of the reaction solution was dispersed in a solution of 12 mL of H ₂ O and 12 mL of hexane. When the particles were dispersed only in the hexane layer, the mixture was cooled to room temperature to obtain a Zr-POSS slurry. In order to finely disperse the agglomerated Zr-POSS slurry liquid, ball milling was carried out at 300 rpm for 20 hours using 5 mm and 10 mm zirconia balls. After ball milling, the Zr-POSS slurry solution was recovered by centrifugation, and the recovered cake was dried at 80 ° C for 8 hours or more to obtain nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: N-phenylaminopropyl) . The dried nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: N-phenylaminopropyl) complex was pulverized using a blender.

Example 2: Synthesis of nano-Zr / R ₈ Si ₈ O ₁₂ Synthesis of -POSS (R: epoxycyclohexyl) complex

A nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: epoxycyclohexyl) complex was prepared in the same manner as in Example 1 except that R ₈ Si ₈ O ₁₂ -POSS (R: epoxycyclohexyl) was used .

Example 3: Synthesis of nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ Synthesis of -POSS (R: phenyl) complex

_{R 7 Si 7 O 8 (OH} ) 3 -POSS (R: phenyl), and the Si, the same manner as in Example 1 nano-Zr / ₇ except that R _{7 O 8 (OH) 3 -POSS} (R: phenyl) Complex.

Example 4: Synthesis of nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ Synthesis of -POSS (R: isobutyl) complex

_{R 7 Si 7 O 8 (OH} ) 3 -POSS (R: isobutyl) the exception that the Example 1 in the same manner as _{nano-Zr / R 7 Si 7} O 8 (OH) 3 -POSS (R: isopropyl Butyl) complex.

Experimental Example 1: Analysis of catalyst characteristics

A specific surface area of Brunauer - was measured by the telephone (Brunauer-Emmett-Teller, BET ) evaluation using the method, and the pore volume of a single point method in the p / p ₀ = 0.99 - Emmett. Pore size distribution was measured by argon sorption technique using the Horvath-Kawazoe method. The morphological characteristics of the catalysts were examined by scanning electron microscope (SEM) (Tescan Mira 3 LMU FEG, accelerating voltage: 10 kV).

division catalyst Specific surface area
(m ² / g) Average pore volume
(cm < ³ > / g) Average pore size
(A) Comparative Example 1 nano-Zr 114 0.361 126 Example 1 nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: N-phenylaminopropyl) 175 0.466 103 Example 2 nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: epoxycyclohexyl) 162 0.441 105 Example 3 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) 165 0.434 105 Example 4 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: isobutyl) 160 0.425 112

As shown in Table 1, the specific surface area (BET) and the average pore volume of the composite catalyst of the POSS nanocage-zirconium-containing nanoparticles prepared in Examples 1 to 4 and the nano-Zr catalyst of Comparative Example 1, The specific surface area and average pore volume of the zirconium catalyst (nano-Zr) of Comparative Example 1 were significantly increased, and the average pore size was remarkably decreased.

When the composite catalyst of POSS nanocage and zirconium-containing nanoparticles prepared in Examples 1 to 4 is dispersed in hexane-water solvent with increasing lipophilicity, zirconium-containing nanoparticles are mainly distributed in the water layer, and POSS nanocage and zirconium- Containing nanoparticles were distributed in the hexane layer (Fig. 3).

The surface structure was analyzed by scanning electron microscope (SEM), and the average size of the crystal grains was about 50 nm (FIG. 4).

Experimental Example 2: MPV reduction reaction and product analysis

To a 100 mL stainless steel reactor equipped with an inner lining of Pyrex glass and a magnetic stirrer, 0.4 g of naphthalene, 10 mmol of EL, 400 mmol of 2-propanol, 0.50 g of catalyst Lt; / RTI > The MPV reduction reaction was performed at a specific temperature for the desired time. The catalyst was separated by filtration and washed thoroughly in an ethanol-water system (95: 5). The filtered liquid was quantitatively analyzed using gas chromatography (GC, FID detector and HP-5 column) and product identification was performed by GC-MS (Agilent 6890N GC and 5973 N MSD).

For open-system solvent reflux, the reaction was carried out in a 100 ml round-bottomed flask equipped with two necks and septum ports and a reflux condenser.

Performance tests of various POSS nanocage and zirconium nanocomposite catalysts, as shown in the following Table 2, were performed for the CTH reaction (MPV reduction reaction) of the EL to GVL as shown in the following Reaction Scheme 1 and the results are shown in Table 2 .

[Reaction Scheme 1]

The above reaction scheme 1 shows the catalytic transfer hydrogenation (CTH) of EL to GVL using nano-Zr / POSS.

division POSS composition
(wt%) Temperature
() time
(hr) Conversion Rate
(%) GVL selectivity
(%) GVL formation rate (mmol / g / hr) One None 130 3 14 30.3 0.283 2 nano-Zr (Comparative Example 1) 130 3 56.6 53.3 1.898 3 nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: N-phenylaminopropyl) (Example 1) 130 3 100 85.1 5.673 4 nano-Zr / R ₈ Si ₈ O ₁₂ -POSS (R: epoxycyclohexyl) (Example 2) 130 3 100 88.6 5.907 5 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) (Example 3) 130 3 98.3 92.5 6.062 6 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: isobutyl) (Example 4) 130 3 96.3 92.3 5.925 7 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) (Example 3) 50 24 100 93.8 0.782 8 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) (Example 3) 80 15 100 92.5 1.233 9 nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) (Example 3) 160 2 100 81.5 8.150

As shown in Table 2, in the case of the nanocomposite catalysts of POSS nanocage and zirconium of Examples 1 to 4, the conversion rate was higher than 40% in comparison with the zirconium (nano-Zr) of Comparative Example 1 and the GVL selectivity Increased by more than 30%. The lower the reaction temperature, the lower the reaction rate and the product formation rate. The higher the reaction temperature, the higher the reaction rate, but the selectivity decreased.

Experimental Example 3: Investigation of reactivity by POSS content

The reactivity of POSS nanocage and zirconium nanoparticle nanocomposite catalysts was investigated by varying the content of POSS as shown in Table 3. At this time, the third embodiment of the _{nano-Zr / R 7 Si 7} O 8 (OH) 3 -POSS: but the synthesis as (R-phenyl) nanocomposite production method POSS content was different, but the reaction is as shown in Experimental Example 2, The reaction time was 3 hours and the reaction temperature was 130 ° C.

division POSS content
(wt%) Conversion Rate
(%) GVL selectivity
(%) GVL formation rate
(mmol / g / hr) One 0.01 72.1 60.3 2.898 2 0.10 88.6 78.3 4.625 3 1.00 95.8 81.1 5.180 4 1.85 98.3 92.5 6.062 5 5.00 98.0 92.1 6.017 6 9.00 90.3 87.3 5.255 7 12.00 63.1 53.8 2.263

As shown in Table 3, when the content of POSS in the composition of the nanocomposite of POSS nanocage and zirconium according to the present invention is 0.10 wt% or less or 10 wt% or more, conversion and selectivity are greatly reduced .

Experimental Example 4: Repeated use of catalyst

A repeated reuse test of the catalyst in the CTH reaction of EL with GVL was carried out. The reaction was carried out as in Experimental Example 2 using the nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) complex catalyst of Example 3, 130 ° C, and the results are shown in Table 4 below. After each cycle, the catalyst was recovered by filtration, washed in an ethanol-water (95: 5) system, and then dried before the next run.

division Number of catalyst regeneration Conversion Rate
(%) GVL selectivity
(%) GVL formation rate
(mmol / g / hr) One One 98.3 92.5 6.062 2 2 98.2 92.3 6.042 3 3 97.8 91.1 5.940 4 4 97.3 91.5 5.935 5 5 96.0 90.1 5.766

As shown in Table 4, only a slight difference in EL conversion and GVL selectivity after 5 cycles was observed, which means that the catalyst of the present invention has a small loss of active sites even after repeated reuse.

Experimental Example 5: Synthesis of nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ Hydrogenation of furfural to furfuryl alcohol using -POSS (R: phenyl)

0.25 g of the nanocomposite catalyst nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl) prepared in Example 3 was dissolved in a mixture of reactant (furfural 0.5 g), hydrogen source (isopropanol 25 g) Was placed in a batch reactor in which 0.25 g of Naphthalene was dissolved. Then, hydrogenation reaction as shown in the following reaction formula 2 was carried out under the reaction conditions of 120 ° C. As a result, the furfural conversion rate was 100% and the furfuryl alcohol selectivity was 96% within 2 hours at 130 ℃.

[Reaction Scheme 2]

Reaction formula 2 shows the transfer hydrogenation of furfural to furfuryl alcohol using nano-Zr / R ₇ Si ₇ O ₈ (OH) ₃ -POSS (R: phenyl).

Claims (14)

Zr-O-Zr, Zr-OH-Zr, or both; And a combined nanosized complex of polysilsesquioxane having a nanocage structure. The nanocomposite according to claim 1, wherein the polysilsesquioxane is represented by the following formula (1) or (2):
[Chemical Formula 1]
R ₈ Si ₈ O ₁₂
Wherein R is selected from the group consisting of linear alkyl of 1 to 20 carbon atoms, branched alkyl, aromatic alkyl, alicyclic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, quaternary alkylammonium Polyalkyleneglycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol, alkylene glycol,
(2)
R ₇ Si ₇ O ₈ (OH) ₃
Wherein R is selected from the group consisting of linear alkyl of 1 to 20 carbon atoms, branched alkyl, aromatic alkyl, alicyclic alkyl, alkylamine, alkylphenylamine, epoxyalkyl, glycidylalkyl, acrylate, methacrylate, quaternary alkylammonium Alkylarylamides, cyanoalkyls, norbornylalkyls, allylalkyls, vinylalkyls or mercaptanalkyls, such as, for example, methylene chloride, methylene chloride, The nanocomposite according to claim 1 or 2, wherein the weight ratio of polysilsesquioxane to Zr-containing nanoparticles is 100: 0.01-10. A catalyst for transfer hydrogenation comprising the nanocomposite as claimed in any one of claims 1 to 3. 5. The process according to claim 4, which is used for the transfer hydrogenation of ethyl levulinate (EL) to gamma-valerolactone. Catalysts for mobile hydrogenation reactions. 5. The process of claim 4, wherein the transfer hydrogenation reaction of furfural to furfuryl alcohol is carried out; Transfer hydrogenation of levulinic acid (LA) to gamma-valerolactone (GVL); Transfer hydrogenation of furfural to 2-methylfuran (2-MF); Transfer hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran (DMF); Transfer hydrogenation of glycerol to 1,2-propanediol (1,2-PDO); Transfer hydrogenation of fructose to 5-hydroxymethylfurfural (HMF); Transfer hydrogenation of glucose to gamma-valerolactone (GVL); Transfer hydrogenation of fructose to gamma-valerolactone (GVL); Transfer hydrogenation of butyl levulinate (BL) to gamma-valerolactone (GVL); Transfer hydrogenation of glycerol to 1,2-propanediol (1,2-PDO); (1-hydroxyethyl) benzene (1-HB) to ethylbenzene; Or 5-hydroxymethyl furfural (HMF) to 1,6-hexanediol (HDL). 5. The process according to claim 4, wherein the hydrogen isothiocyanate is selected from the group consisting of hydrogenated isopropanol, methanol, ethanol, glycerol, butanol, cyclic ether, benzyl alcohol, cyclohexanone, 2-propanol, ethylene glycol, 2,3-dihydroindole, , 4-tetrahydroquinoline, cyclohexene, cyclohexane diene, limonene, hydrazine, ammonium formate, ammonium hypophosphite or mixtures thereof is used to carry out the mobile hydrogenation reaction. The catalyst for a mobile hydrogenation reaction according to claim 4, which is used for a mobile hydrogenation reaction at a low temperature of 200 ° C or lower. The catalyst for the mobile hydrogenation reaction according to claim 4, which is used for an open-system mobile hydrogenation reaction using a solvent reflux method. A process for producing gamma-valerolactone through the use of a catalyst according to claim 4, wherein the gamma-valerolactone is subjected to a mobile hydrogenation reaction of ethyl levulinate (EL). 11. The process according to claim 10, wherein the hydrogen isothiocyanate is selected from the group consisting of hydrogenated isopropanol, methanol, ethanol, glycerol, butanol, cyclic ether, benzyl alcohol, cyclohexanone, 2-propanol, ethylene glycol, 2,3-dihydroindole, , 4-tetrahydroquinoline, cyclohexene, cyclohexane diene, limonene, hydrazine, ammonium formate, ammonium hypophosphite or mixtures thereof is used to carry out the mobile hydrogenation reaction. 11. The process of claim 10, wherein a mobile hydrogenation reaction is carried out in an inhomogeneous catalyst system. 11. The process of claim 10, wherein the mobile hydrogenation of ethyl levulinate (EL) is carried out in an open system using an inhomogeneous catalyst and a solvent reflux process. A process for producing a furfural alcohol through a mobile hydrogenation reaction of furfural using the catalyst according to claim 4.

Images