Tom Tat Luan An Ta Nghiên Cứu Phản Ứng Hydroformyl Hóa Ethylene Với Co Và Co2 Sử Dụng Xúc Tác Tẩm Chất Lỏng Ion Silptio2 Và Nano Autio2 (Sio2).Pdf

Compared to the first phase, the catalytic of the second phase has higher activity, softer working conditions, but fails to overcome disadvantages such as product separation from the rea

MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY

TRUONG DUC DUC STUDY ON THE HYDROFORMYLATION OF ETHYLENE

Major: Chemical Engineering Code: 9520301

SUMMARY OF THE CHEMICAL ENGINEERING

DOCTORAL THESIS

Thesis has been completed at: Hanoi University of Science and Technology

Scientific supervisor: Prof.Dr Le Minh Thang

Reviewer 1: Reviewer 2: Reviewer 3:

This thesis was defended at the Doctoral Evaluating Council held at Academy level at Hanoi University of Science and Technology

At… , ………, 2024

The thesis can be found at:

1 Tạ Quang Bửu Library- Hanoi University of Science and Technology

2 Vietnam National Library.

1 Introduction 1.1 The imperiousness of the thesis

Hydroformylation is one of the oldest synthesis processes and is the most characteristic of homogeneous catalyst reactions that modify andehydes from olefins This process was discovered in 1938 by Otto Roelen and was introduced into the manufacturing industry in the 1949s by BASF, Ruhrchemie process (Germany) In a homogeneous hydroformylation reaction that occurs in a high-pressure liquid phase, olefins react with synthetic gases (CO and H2) in the presence of metal complex catalysts that produce andehytes This process is commonly referred to as oxo synthesis, with oxo being the abbreviation of "Oxonation", which means the oxygenation of a molecule Oxo products (including andehit and ancol) are of particular value in industry, from oxo products that can produce ancol and carboxylic acid from which applications into chemical, chemicals, polymers and plastics, detergents, and other intermediates of high economic value…

The hydroformylation reaction has undergone three stages of development of catalysts In the early stages of the history of hydroformylation, Coban (Co) was used as a catalyst for hydroforylation reactions at a pressure of 15-30MPa and temperatures between 120-190oC Currently, Co is used in its active form as cobalt carbonyl hydride (0.05-3% by volume) The H2:CO input ratio ranges from 0.9:1 to 1.5:1 However, this catalyst has low activity, harsh reaction conditions, difficulty separating the product from the reaction mixture In the second phase of development, the catalyst of the hydroformylation reaction was developed in a combination of ligand improvement and cobalt metal center replacement with rhodium (Rh) In 1974, the first commercial rhodium catalyst was introduced, known as the low-pressure oxidation process (LPO) Since the 1970s, most people have used Rhodium-based catalysts (Rh) Rh is about 102-103 times more active than cobalt Especially if it's a low-pressure reaction of between 7 and 20 MPa Compared to the first phase, the catalytic of the second phase has higher activity, softer working conditions, but fails to overcome disadvantages such as product separation from the reaction mixture, catalyst regeneration, loss of precious metals in the catalyst, use of corrosive solvents In the third phase of development, the catalyst for the hydroformylation process is improved in the direction of changing the environment in which the reaction is carried out: from homogeneous to two-phase liquid-liquid (biphasic) allergens, in which one phase is an organic phase soluble in water reactors and reaction products (CO, H2, C2H4 and oxo products) and the other is a phase preferred to solve catalytic water on the basis of the Rh complex, this is aimed at solving the problem of catalyst regeneration, separating reactive products more easily The hydroformylation process has so far been known as one of the typical homogeneous processes In addition to the advantages of the homogenization process (high efficiency), there are the disadvantages: it is difficult to separate the reactive product from the reaction environment; the Rh catalyst is vulnerable to loss, not recoverable When Ionic Liquid (IL) is applied to replace the traditional solvent so that the hydroformyl reaction can be carried out in the form of a two-phase liquid (biphasic) has prompted hydro-formylation to a new phase However, biphasic has disadvantages such as the use of large amounts of IL, IL with high viscosity, the speed of reaction will be limited by the ability to diffuse the product out of the reaction block is limited In addition to the above difficulties, the safety issue is also worth paying attention when the hydroformylation process is carried out with the presence of CO and H2 at high pressure (about 20 MPa) with the risk of potential explosion and especially CO is toxic gas leakage that is dangerous to life and human health in production

Hence the recent catalytic study of hydroformylation reactions focuses on two main directions: The first is heterogenization of catalysts based on the "Supported Ionic Liquid Catalysis (SILP)" first proposed by Prof Rasmus Fehrmann and colleagues in 2002 In the SILP system: a thin film of Ionic Liquid (IL) containing a liquid complex catalyst that is positioned fixed onto a foam-bearing material with a large surface area The reaction occurs in the liquid ionic membrane as in the homogeneous environment With thin membranes, limit the dependence on the viscosity of IL, reduce the amount of

IL used, eliminate the limit of the diffusion through the catalytic block of the reagent Because it is carried on a solid carrier, the SILP catalyst ensures that the catalyst is easily separated and recovered SILP has demonstrated superiority by overcoming its shortcomings as well as bridging the advantages between homogeneous and malignant processes; The second direction is to replace CO in synthetic materials with less toxic and cheaper sources CO2 is a potential candidate for this alternative, in addition to being an inexpensive, easy-to-reach source of raw materials, CO2 being also chosen because it's a climate change agent The replacement of CO2 with CO2 will simultaneously reach two targets of reducing the risk of toxicity as well as reducing environmental damage to green and sustainable production processes The idea of using CO2 to transform H2 and C2H4 into propanol was proposed by Professor Evgenii V Kondratenko and colleagues from the LIKAT Catalytic Research Institute (Germany) in 2014 on the basis of the Au nano particles catalyst The process is performed under soft pressure conditions (about 10MPa) and should be safe for operation However, initial results show that the CO2 conversion and oxygen selectivity (according to ethylene products) are still very low (less than 1 per cent) due to the inhibition of the hydrogenation reaction of ethanol into ethane The hydroformylation process of ethylene is currently conducted only in homogeneous form, but it cannot be conducted in a biphasic batch because propanal forms an azeotrope mixture with water that prevents the separation of the product So, improving the catalyst research for the hydroformylation reaction of ethylene into oxo products (propanal and propanol) based on both of these approaches is important, it is an urgent task and in line with the world's research trend towards green, sustainable production and environmental protection

1.2 The mission of research

- Synthesizing TiO2 by hydrothermal crystallization - Synthetic study of SLIP catalysts on a complex basis [Rh-TPPTS Cs3] dissolved in the thin membrane of liquid ions and carried on the solid support TiO2 in varying ratios

- Study the synthesis of Au nano-catalysts on TiO2 supports using different synthesizing processes to optimize the synthetic process

- A study of synthesis of Au nanocatalysts on SiO2 supports in different ratios to investigate the optimal ratios of Au particle size adjustment

- Synthetic catalysts SLIP/TiO2, Au/TiO2 and Au/SiO2 - Study the Rh ratio: ionic liquid, optimal Au loading content, Au particle size, ratio of reactive ingredients, general reactive pressure to catalytic activity

- Proposed and improved reactors to overcome the kinetic constraints of the direct synthesis of CO2, H2

and C2H4 into oxygen products (including propanal and propanol) on the basis of Au/SiO2 catalysts to improve CO2 conversion efficiency and increase the selectivity of Oxo Products according to C2H4substances

1.3 The subjects of research

- Supported ionic liquid phase (SILP) catalyst using 1-butyl-3-methylimidazolium octylsulfate ionic fluid ([BMIM][n-C8H17OSO3]), acetylacetonato-dicarbonyl-rhodium (I) (Rh(CO)2(acacac)), ligand is a sodium salt of 3.3’,3’’-phosphinetriylbenzene-sulfonic acid (TPPTS-Na3) carrying TiO2 supports - Au/TiO2 and Au/SiO2

- Hydroformylation reaction of ethylene with H2, CO, and/or CO2, H2, forming oxo products (propanal and propanol)

1.4 Scientific and practical significance of the thesis

- Research aimed at improving our understanding of the effects of TiO2 support properties (stable, inert, stable and non-surface acidity) on the activity of SILP catalysts that previous studies have not clearly demonstrated

- Initial research revealed outstanding results in improving CO2 conversion and significantly increasing selectivity of oxo products based to C2H4 feedstock due to the improvement of "two-phase reactive

equipment" (dual – reactor system) The thesis proposed a new idea to overcome the thermodynamic drawbacks and kinetic barriers of multi-stage reaction processes The thesis has made important contributions to improve catalytic activity for hydroformylation of ethylene as well as CO2 conversion contributing to enhanced catalyst efficiency and reduced greenhouse effect toward to sustainable development

1.5 New discoveries of the thesis

- Studies have shown that the effects of the surface acidic properties of TiO2 and SiO2 supports have only minor effects on the catalytic activities due to the formation of the aldols products, which indicate that catalytic activity is strongly dependent on pore size, the pore volume and the surface area of the catalyts

- The study revealed Au/TiO2 has minor activity for traditional hydroformylation of ethylene with CO and H2 However, its activity has much lower than that of a catalyst based on the Rh complex of SILP/TiO2

- C2H4 hydroformylation took place with a substitute CO2 reactant for a traditional CO reactant based on an Au/SiO2 catalyst for remarkable activity with oxo products selectivity of 60% and ethylene yield of 13% at 175oC

- The catalytic activity of Au/SiO2 is strongly dependent on the size of the Au NP, resulting in Au nanoparticles in the range of 4–8nm for the highest catalytical activity

- A dual-reactor system can overcomes the thermodynamic drawbacks of a chemical process which includes a variety of different multi-reactions as well as optimized feedstock and reaction conditions, thereby increasing the overall efficiency of the process This has made a major contribution to science

1.6 The structure of the thesis

The thesis consists of four main chapters Chapter 1 presents a theoretical overview, Chapter 2 presents the experimental process, chapter 3 exchanges results and discussions, and Chapter 4 is the main conclusions and new contributions of the thesis

1.7 Overview of the thesis 1.7.1 Hydroformylation of anken overview

The anken hydroformylation process is an important industrial homogeneous synthesis process for transforming olefins and synthetic gases (CO and H2) into oxo products (andehit) with many important applications in the chemical industry:

“normal” “branched”

Figure 1.2 Depiction of hydroformylation of olefins The process is carried out at high pressure (50 – 300 bar), optimal temperature (below 200oC) on the basis of Coban (Co) or Rhodium catalysts (Rh) The improvement of initial catalyst HCo(CO)4 with catalyst HRh( CO)4 increases catalyst activity hundreds of times while reducing less severe threshold response conditions (10 – 60bar) But the big problem remains that the homogeneous reaction makes it difficult to separate the catalyst from the mixture after the reaction leads to catalytic loss In order to increase catalyst activity and reduce reaction conditions, complex [Rh-TPPTS] catalysts are dissolved in ionic fluids and carry on solid carriers such as SiO2, SBA-15, ZrO2 known as the SILP - supported ionic liquid phase catalyst opens up promising prospects to enhance catalytic activity, reduce the reaction condition, and easily separate the catalyst from the post-reaction product mixture SILP is basically composed of three main components, the active phase of the catalyst is a complex form of Rh

with tri-cesium ligand 3,3’,3’’-phosphinetriylbenzene-sulfonate (TPPTS-Cs3) dissolved in ionic liquid 1-butyl-3-methylimidazolium octylsulfate ([BMIM][n-C8H17OSO3]) The mixture is then soaked onto the surface of a solid carrier containing SiO2, SBA-15, zeolite, Al2O3 following a very rigorous process to ensure a thin membrane layer and restriction of oxidation by O2 in the environment that can lead to loss of catalyst activity.

1.7.2 Overview of hydroformylation of ethylene with CO2 and H2

CO2 is considered as a major contributor to global climate change, and finding solutions to reducing CO2 levels in the air is an urgent concern for scientists around the world The solution is given in three main directions: One is the storage of CO2 in liquid form and buried underground, a technique that requires high-technology and huge investment; The second is the reduction of CO2

emissions to the atmosphere by limiting or replacing production processes and transport operations, a solution that requires long-term and consciousness of each government and leader of each country; Thirdly, the solution uses CO2 as an input source for processes that turn it into more economically valuable chemicals, and the third solution is interested in chemists because it fits the current technology and is proactive and flexible at the right cost To solve the third option, the scientists focus on finding the right catalyst to convert CO2 into intermediates and then continue to convert these intermediates into the end products of polymers, plastics, dyes It serves the lives of human beings One of the big challenges is that the thermodynamic sustainability of CO2 requires strong catalyst activity and harsh metabolic conditions So far, only a few catalysts have been found and put into industrial production such as methane synthesis, methanol, formic acid [65, 66] One of the products of CO2 conversion is the reverse water-gas shift reaction (RWGS):

The CO obtained in combination with H2 forms a "synthesis gas" mixture, which can be synthesized into many valuable organic chemicals For example, through Fischer-Tropsch reactions with catalysts based on iron or cobalt, higher circuit hydrocarbons are obtained However, the difficulty of applying RWGS to the manufacturing industry is because the requirment of a large supply of energy, so in order to be more efficient in the use of energy it is necessary to optimally utilize the total energy source as well as the product produced must have a high economic value that compensates for the cost of energy In fact, propylene is seen as a highly economically valuable intermediate in the polymer industry to produce polypropylene (PP) plastic products that are widely used in life Propylene can be easily produced from 1-propanol through dehydration, so the direct process of converting CO2, H2 and C2H4 into 1-propylene is a “green and sustainable” chemistry suggested by Professor Kondratenko and colleagues [72] The reaction is carried out directly with catalysts on the basis of Au supported that are modified with the trigger metal K, Li, Na:

Initial results suggested that is a promising direction where CO2 conversion is about 10% conversion and 1-propanol selectivity is about 1% based on C2H4 In addition to the desired main product, 1-propanol, the by-product is mostly C2H6 (99%) The CO2 conversion is still below the research expectations When considering the mechanism of the reaction, he suggested the reaction was a multi-stage process, initially the RWGS reaction was carried out to produce in-situ CO, followed by the hydroformylation reaction of C2H4, H2 and CO to form propanal, the final phase of which was the hydration of propanals into 1-propanol

RWGS reaction: CO2 + H2 ↔ CO + H2O (∆ H = 39 kJ mol-1) (i) Hydroformylation: CO+C2H4+H2→ C2H5CHO (∆ H = −130 kJ mol-1) (ii)

Hydrogenation: C2H5CHO + H2 → C3H7OH (∆ H = −77 kJ mol-1) (iii) The biggest advantage of this process is that the use of in situ CO that is generated directly from CO2instead of the initial direct use of CO in the raw material will greatly reduce the toxicity harassment from the process Moreover, increasing CO2 conversion efficiency and improving 1-propanol selectivity will make this process a green and sustainable process

The catalyst for the process that has been found so far is an Au-based catalyst on SiO2 and TiO2

supports (anatas), the addition of a small amount of alkaline metal (K, Li, Na) indicates an increase in CO2 conversion While TiO2 carrier possessed a higher CO2 conversion activity, SiO2 has a slightly superior 1-propanol selectivity [72, 73, 74, 80] These studies have been proposed recently since 2014, so the role of the promotor (alkaline metal) as well as the effects of the supports, the effect of the Au-nano-size, and many other factors are still unclear Particularly low catalytic efficiency with low CO2conversion (<10%) and very low 1-propanol selectivity based on C2H4 feedstock (<1%) are limitations that need to be improved in future studies

2 Experimental methods 2.1 Preparation of SILP catalyst

- Ligand is a sodium salt of 3.3',3''-phosphinetriylbenzene-sulfonic acid (TPPTS-Na3) synthesized from the precursors of Triphenylphospin (TPPs), Fuming sulfuric acid/oleum, Toluene, Trioctylamine, Octylamine Cesium hydroxide monohydrate, methanol through the following major steps: Sunphonation within a week at 20oC, diluted with water, forming intermediate compounds, phase separation and neutralization with NaOH to pH 5.5 - 6.5

- TiO2 carrier is synthesized by hydrothermal crystallization from the precursor Tetra-isopropyl orthotitanate C12H28O¬4Ti (TTIP), Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) PEG-PPG-PEG (P123), citric acid monohydrate C6H8O7.H2O, sulfuric acid and isopropanol The synthesis process goes through the main steps: Sol formation by adding the TTIP diluted homogeneous solution and the P123 framing agent in the isopropanol with the addition of the appropriate amount of sulfuric acid and citric acid (solution B) slowly into the diluted solution of the water-isopropanole mixture (Solution A) under room temperature conditions and intensive mixing to form the homogenous solution Sol formation is stable to produce a sustainable sol-gel system and hydrothermal crystallization at 90°C for 20 hours The product is filtered, dried and boiled at 400 °C, obtained in the form of TiO2 anatas

- SILP is synthesized on the Schlenk synthesis diagram described in Figure 2.2 Flask A: accurate quantity [Rh(acac)(CO)2], ligand, ionic liquid Then proceed to vacuum and infuse inert air (Ar) inside A quantity of methanol (MeOH) has been discharged into the air, charging the inert gas contained in a closed vessel Flask B: The exact quantity of the carrier (TiO2 anatas) Proceed to take MeOH by cylinder in the amount calculated, transferred to the A vessel, put up the magnetic mixture to the reaction between [Rh(acac)(CO)2] and the ligand occurred, after about 2-4h obtaining a yellow homogeneous solution Use a cylinder to absorb the solution A completely and put it into the container B and continue mixing the solution for 30 minutes Then we evaporate MeOH by heating the synthetic vessel at a temperature of 68-70°C, and then we turn the vacuum into a solid that we obtained as a SILP catalyst, to dry it thoroughly so that MeOH is loaded into the schlenk line system to suck vacuum and blow the inert air for the next two to four hours The catalytic is pale yellow

2.2 Preparation of nano Au/TiO2 catalyst 2.2.1 Preparation of Au/TiO2 using different methods

Au/TiO2 smoothies are synthesized using four different techniques including: hydrothermal crystallization, Cl-filter mixed soaking, vaporized mixed smoothing and sol-gel method * Deposition–precipitation: The 0.5-Au_TiO2 QT1 catalyst is synthesized by accurately weighing 2.00 grams of TiO2 into 200 ml of 0.314 mM HAuCl4 solution mixed for 30 minutes, then adding from

the NH3 solution (25%) until the pH reaches 10.5 The solution then aged for 10 minutes, eventually filtered to completely cl- (tested with AgNO3) The solid dries at 80°C in the air to dry completely

Figure 2.2 The Schlenk system to synthesize of catalysts Table 2.1 lists the synthetic catalysts and their components

Table 2.1 Summary of synthesized SILP catalysts

(mol/mol)

IL content (%V pore)

Rh content (%w)

* Combined evaporative impregnation: a 0.5-Au_TiO2 QT3 catalyst is synthesized using the usual impregnating process, but instead of filtration to eliminate Cl-, we put NH3 (25%) in the fluid with a surplus and then proceed with evaporation to remove Cl- due to NH4Cl that can elevate when heated The removal of Cl- in this way is because we believe that the catalytic cleaning process will lose some of the Au metal due to the initial unstable surface adhesion

*Sol-gel method: 0.5Au_TiO2 QT4 is synthesized by adding 25ml of acetic acid (98%) to a solution containing 100ml of iso-propanol and 10ml of Tetra-isopropyl orthotitanate C12H28O¬4Ti (TTIP) to obtain a homogeneous solution (solution A) Solution A is then gradually driped to 200ml of 0.314mM

HAuCl4 solution under intense mixing conditions at studio temperature obtained gel B solution Gel B is aged for an hour at room temperature Finally, 5ml of NH3 solution (25%) was added to make the Au(OH)3 The product is then dried and boiled at 450°C Synthetic Au/TiO2 catalyst samples in different processes are synthesized according to table 2.2

Table 2.2 Summary of synthesized Au/TiO2-based catalysts using different methods

method

Au loading weigh [%wt][a]

[a]: Au loading weigh % content determined by theory

2.2.2 Preparation of nano particles gold on SiO2 support catalysts with different Au loading amounts (0.5% - 4.0%)/ different Au NP sizes/ different supports

Au/SiO2 was prepared through deposition−precipitation (DP) of gold hydroxide from HAuCl4 (41.1 wt %Au, Chempur) on the support as follows 2 g of SiO2 powder were added at room temperature under continuous stirring to a 1.57 mM HAuCl4 solution (200 ml) and further stirred for 20 min Afterward, NH3 solution (25%, Roth) was slowly added until the pH value of 10 was reached After 10 min aging phase, the solid was filtered, washed, and finally dried in air at 80 °C to yield Au/SiO2 The 1Au/SiO2-x samples (where “x” stands for Au NP size which calculated by XRD parterns) are synthesized by HAuCl4 concentrations of 3.34mM, 6.68mM, 10.02mM, 10.36mM and 16.7mM, respectively as well as pH changing from 6, 7, 8, 9 and 10, respectively (Table 2.3)

Table 2.3 Summary of synthesized supported gold catalysts

Catalyst Au loading

weigh [%wt]

Support Procedure

0,5Au/SiO2 0.5 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution 1Au/SiO2 1.0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution 2Au/SiO2 2.0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution 4Au/SiO2 4.0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution 1Au/SiO2-2nm 1,0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution/ 3.34mM HAuCl4, pH = 6 1Au/SiO2-3nm 1,0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution/ 6.68mM HAuCl4, pH = 7 1Au/SiO2-4nm 1,0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution/ 10.02mM HAuCl4, pH = 8 1Au/SiO2-5nm 1,0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution/ 10.36mM HAuCl4, pH = 9 1Au/SiO2-6nm 1,0 SiO2 QT1: Depositon - Prepicipitation (DP) using

NH3 solution/ 16.7mM HAuCl4, pH = 10

All samples were prepared by adding 1%Au loading content on supports following DP method (QT1) (Table 2.5)

Table 2.5 Summary of 1%Au loading content on different supports

based surface 1Au/Al2O3-n 1.0 -Al2O3 99% purity, 220-280 m2.g-1, Alfa Aesar /

neutralized surface 1Au/ZrO2+SiO2 1.0 ZrO2+ SiO2 ZrO2 (99.9% purity, particle size 20-

30nm, surface area >35 m2.g-1, Chempur)/ (50%ZrO2 + 50%SiO2) mixture

surface area >7.3 m2.g-1, Chempur

1Au/TiO2 1.0 TiO2 100Ao, 106 m2.g-1 (home made)

1Au/SiO2 1.0 SiO2 248 m2.g-1, particle size 0.06-0.2 mm,

pore volume 0.966 mL.g-1, Merck

1Au/SBA-15 1.0 SBA-15 home made, SBET = 445 m2.g-1, pore

diameter > 100Ao

1Au/HZSM-5 1.0 HZSM-5 home made, SBET = 267 m2.g-1

1Au/SAPO-34 1.0 SAPO-34 home made, SBET = 421 m2.g-1, mean

pore diameter 50Ao

1Au/CeO2 1.0 CeO2 99.9% purity, particle size 15-30nm,

surface area 30-50 m2.g-1, Chempur2.3 Methods to determine the composition and chemical characteristics of catalysts

Prepared samples were characterized by Infrared spectrum (IR) on Thermol Nicolet 6500 (HUST); specific surface area BET on BELSORP – mini II, Japan (LIKAT) and a Micromeritics ASAP 2010, USA (HUST); X-ray interference (XRD) on D8 Bruker Advanced diffactometer (Laboratory of the Petrochemical Refinering and Catalytic Materials, School of Chemical Engineering, Hanoi University of Science and Technology) and X’Pert Pro (Panalytical, Almelo) (LIKAT); TEM electron microscopy on JEM2100 microscope operated at 200 kV (Institute of Materials Science, VAST, Vietnam); nuclear

31P-NMR spectroscopy, 500MHz NMR Spectroscope; Pulse CO absorption on AutoChem 2920 II – Micromeritics device (Laborotory of Environmental Friendly Material and Technologies, HUST); X-ray electron spectroscopy (XPS) on VG ESCALAB 220iXL instrument with monochromatic Al Kα radiation (E = 1486.6 eV) (LIKAT); electronic magnetic resonance spectrum (EPR) on ERP devices supported by RoHan project for Laboratory of Environmental Friendly Materials and Technologies (HUST); auto-sensitive combined plasma atomic radiation spectre (ICP-OES) on ICP-EOS Varian 715 instrument at LIKAT, Germany

2.4 Methods to test Catalytic Activity 2.4.1 Methods for testing the catalyst activity of SILP_TiO2 and Au/TiO2 for ethylene hydroformylation reactions

SILP_TiO2 and Au/TiO2, catalysts for the hydroformylation reaction of ethylene to propanal were evaluated on the micro-line reactor connected to Trace GC Ultra online using FID detector, Fused Silica Capillary Column (30 m × 0.32 mm × 0.25 μm) Catalytic activity was investigated in the temperature range of 80 – 140°C, initial raw material ratio C2H4:CO:H2 = 1:1:1, total raw material flow pressure of 1 MPa The amount of catalyst used is 200mg, the total gas flow is 30ml per minute

The yield of propanal or propanol (oxo products) based on C2H4 (Y(i, C2H4)) was calculated using eq 2.21, under the consideration that one C2H4 is converted into propanal or propanol

[7] (2.21) Where, n (C2H4,inlet) stands for the mole flow of C2H4 at the reactor inlet and ni stands for the mole

flows of product i at the reactor outlet The conversion (X) of C2H4 was calculated according to eq 2.22 from the sum of oxo yields and the yield of ethane calculated from eq 2.21

Selectivity of oxo products (propanal and propanol) in the hydroformylation of ethylene was calculated as:

[7] (2.23) The residence time τ was calculated from the formula:

τ

[7] (2.24)where nRhodium: molar of Rh in catalytic samples

The hydroformylation activity of the catalysts were determined at isothermal conditions mainly through turn-over-frequency (TOF) values, which were calculated from the molar flow of the main product propanal divided by the amount of rhodium:

[7] (2.25) Where

Faldehyde is the total molar flow of produced aldehyde (propanal) (mol/h), Falkene the total molar flow of alkene (ethylene) (mol/h),

][sFtotalnRhodium

Figure 2.16: (a) A dual – reactor concept diagram and (b) real design reactor system at LIKAT

nRhodium the moles of Rh metal in the catalyst bed (mol), and X the fractional conversion of ethylene

According to the law of conservation of mater: Ftotal (inlet) = Ftotal (outlet) Total molar flow of reactants: Ftotal = (P*V)/(R*T) (2.26) Where

P – total pressure of mixture gas (bar) V – total flow rate (l/h)

R – gas constant : 0.082 [l.at/mol.K] T – temperature (K)

The rate of reaction was calculated from the converted ethylene and the residence time:

[7] (2.27) where p is partial pressure of introduced alkene

2.4.2 Methods for determining xCs-yAu/SiO2 catalyst activity for C2H4, H2 and CO2conversion reactions into oxo products (propanol + propanal)

The idea of improving the catalytic activity assessment system is based on the study of the mechanism of the process, according to which the process takes place in three phases in which the first phase of the thermodynamic RWGS reaction will proceed favourably at high temperatures, while the next phase is the hydroformylation and hydrogenation processes favourable thermodynie at low temperatures This led to the idea of dividing the total process into two separation phases, each of which proceeds at different temperatures The first phase is carried out at high temperatures to prioritize CO2 conversion, in the subsequent phase of gas conducted at low temperature to optimize the hydroformylation reaction, C2H4 is only added to the raw material stream for the later phase to avoid side reactions and optimize for hydro formylation So, in this thesis, the idea of a dual-reactor is designed and constructed Catalytic activity assessment devices designed with two reactors directly connected to each other are called "two-phase reaction devices" (dua-reactor system) The raw material consists of CO2 (4.5, Air Liquide), H2 (5.0, Air Lique), C2H4 (3.0, Linde), and N2 (5.0, Air Liquide) The first reactor received 300mg of 2AuSiO2 catalyst (fixed particle size 250–450 μm), the temperature was kept stable at 650oC, the raw material flow into 2Mpa pressure, the CO2/H2/N2 input ratio was 1:1:1 The purpose of the first reactor is to carry out the RWGS reaction that produces CO at optimal conversion before entering the second reactor The second reactor was loaded with 1000mg of Au/SiO2 catalyst to be tested, and the temperature range at the second was changed from 150°C to 250°C The C2H4 series (3.0, Linde) was added to the product line after the first reactor to the theoretical reaction ratio CO2/H2/C2H4/N2 = 1: 1: 1: 1 : 1 (corresponding to the storage time of the catalyst to be tested is 50 g.Min.L-1) Before the reaction, the first reactor runs stable at 650 °C while the second reactor is heated to 300 °C within 3 hours, the C2H4 stream is disconnected to deactivate the Au3+ state to the Au0 state on the catalyst to respond to the subsequent reaction System connected to on-line GC (Varian CP-3800) equipped with a FID (HP Plot Q) and a TCD (HP-Plot Q & Molsieve 5A) The diagram describes the two-phase reaction device as described in Figure 2.16

The parameters for evaluating catalyst activity are calculated according to the following formula: Y (i, C2H4) = ,

ùû

𝛼 =

Where ni,0 and ni stand for the mole flow of the feed components and the mole flow of the reaction products, respectively Subscript “0” is used for the inlet mole flow The CO/H2 ratio, which is an important parameter for the hydroformylation reaction, was calculated according to (2.32) equation with the consideration that one CO2 reacts with one H2 to form one CO

3 Results and discussion 3.1 Characterization of ligand TPPTS

For the Ligand TPPTS-Na3 synthesis, IR spectrum results were compared with the results of the previous group of researchers

The fluctuation characteristics of the sulfonic group appeared at 1200, 1100 and 1050 cm-1, the P-C groups at 1641cm-1, S-O at 620cm-1, C-H at 993, 817, 799, 792 cm-1, fluctuations of the phenyl group at 690cm-1 were similarly observed on the IR spectrum of the TPPTS-Cs3 ligand This confirms that the synthetic TPPTS-Na3 catalyst from this study is perfectly consistent with the TPPTS catalyst that was proven by previous authors

Figure 3.8 1H - NMR spectrum of synthesized TPPTS-Cs3 ligand (left) and TPPTS-Na3 ligand (right)

1200 1100

620

Figure 3.1 FT-IR spectrums of TPPTS-Cs3 and TPPTS-Na3 ligands

Figure 3.7: EPR spectra of 0,5Au_TiO2

samples recorded at room temperature