Patent Application
20220055016
The present invention relates to the production of butanol, and more specifically to the production of butanol using a titanium-based bimetallic heterogeneous catalyst.
Demand for biofuels as a substitute for petroleum is expected to increase because of economic and environmental concerns. The common biofuel is ethanol and it has been applied in automobiles with gasoline in different blending proportions. However, ethanol, is not ideal because it has a lower energy density than gasoline and must be mixed with gasoline at a limited concentration range in order to serve as a transportation fuel. Ethanol is also hygroscopic and corrosive, which poses a problem for storage, distribution systems and automotive over time.
On the other hand, butanol also can be used as fuel, which attracted people's attention in recent years. Because of the good properties of high heat value, high viscosity, low volatility, high hydrophobicity, less corrosive, butanol has the potential to be a good fuel in the future. When ethanol is mixed with gasoline (less than 10%), there exists some disadvantages. Firstly, the heating value of ethanol is one sixth of gasoline. The fuel consumption will increase 5% if the engine is not retrofitted. Secondly, acetic acid will be produced during the burning process of ethanol, which is corrosive to the materials of vehicle. Thirdly, ethanol is hydroscopic but poorly soluble in gasoline, so the liquid phase separation may be occurring with high water proportion, provoking damages in automotive. Furthermore, ethanol as fuel cannot be preserved easily and it is more difficult in the process of allocation, storage, transition than that of gasoline due to its high vapor pressure. Compared with ethanol, butanol overcomes above disadvantages and it shows potential advantages. For example, butanol has higher energy content and higher burning efficiency, which can be used for longer distance. The air to fuel ratio and the energy content of butanol are closer to gasoline. Thus, butanol can be easily mixed with gasoline in any proportion. Butanol is less volatile and explosive, has higher flash point, and lower vapor pressure, which makes it safer to handle and can be shipped through existing fuel pipelines. In addition, butanol can be used directly or blended with gasoline or diesel without any vehicle retrofit.
Butanol can be obtained from the process of fermentation by bacteria (ABE fermentation) as one of the products, in this case called biobutanol. However, the production of butanol by ABE fermentation has several disadvantages related to cost issues, the relatively low-yield and sluggish fermentations, as well as problems caused by end product inhibition and phage infections. Additionally, butanol is produced as only one of several products, so further processes for recovery are necessary to implement. In this sense, according to the atom economy concept, which is an extremely useful tool for evaluating the amount of waste generated by alternative routes to a specific product and one of the 12 “principles of green chemistry” (The Atom Economy-A Search for Synthetic Efficiency; Barry M. Trost; Science 1991, (254), pp 1471-1477), the atom economy for the production of butanol by ABE fermentation is very poor. Atom economy is calculated by dividing the molecular weight of the desired product by the sum total of the molecular weights of all substances produced in the stoichiometric equation for the reactions involved.
It is also possible to produce butanol using chemical technologies, such as oxo-synthesis, catalytic hydrogenation of carbon monoxide and aldol condensation. However, these processes use starting materials derived from petrochemicals and are generally expensive and are not environmentally friendly. The efficient production of butanol from plant-derived raw materials, as cereal crops, sugar cane, sugar beet and cellulosic raw materials, would minimize green house gas emissions and would represent an advance in the art if their atom economy also is above 90%.
In this sense, bimetallic catalysts have attracted extensive attention for a wide range of applications in energy production and environmental remediation due to their tunable chemical/physical properties. These properties are mainly governed by a number of parameters such as compositions of the bimetallic systems, their preparation method, and their morphostructure. In this regard, numerous efforts have been made to develop bimetallic catalysts with specific nanostructures and surface properties as a result of recent advances in the area of materials chemistry. As an example, patent document WO2019186253A1 describes a catalyst comprising a titanium dioxide support doped with titanium (IV) cations which is impregnated with metal nanoparticles such as gold, cobalt and palladium. This catalyst is used to produce butanol from ethanol. However, the main technical problems of the catalyst described in this patent document are that the metal nanoparticles have low stability as they are deposited on the surface of a reducible oxide; loss of catalytic activity, a weak nanoparticle-support; and high percentages of metal used. Also, during the formation of the catalyst described in patent document WO2019186253A1 urea is used as a precipitation agent.
Considering the drawbacks of the methods found in the prior art for the production of butanol, as described above, there is a need for an environmentally responsible, cost-effective process for the production of butanol as a single product. The present invention addresses this need by providing a method for the production of butanol using a titanium-based bimetallic heterogeneous catalyst with enhanced selectivity, activity, and stability, among other advantages.
Considering the problems and disadvantages of the prior art mentioned above, it is an object of the present invention to provide a titanium-based bimetallic heterogeneous catalyst with enhanced selectivity, activity, and stability.
Another object of the present invention is to provide a manufacturing process for the preparation of a titanium-based bimetallic heterogeneous catalyst.
Another object of the present invention is to provide a method for the more efficient production of butanol using a titanium-based bimetallic heterogeneous catalyst, with an atom economy above 90%.
It is another object of the present invention to provide a butanol obtained by heterogeneous catalysis to be used as a biofuel with a vapor pressure of less than 1.53 kPa and a purity of at least 96%.
These and other objects are accomplished by a method for the production of butanol using a Titanium-based bimetallic heterogeneous catalyst in accordance with the present invention.
The present invention relates to a titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support.
Also, the present invention relates to a manufacturing process of a titanium-based bimetallic heterogeneous catalyst comprising the following steps: a) mixing titanium dioxide with a cobalt salt to obtain a support of titanium dioxide doped with cobalt cations; b) adding to the support of titanium dioxide doped with cobalt cations at least one transition metal salt solution to obtain a titanium-based bimetallic heterogeneous catalyst comprising titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support.
Another aspect of the present invention relates to a method for the production of butanol comprising the step of introducing a feed of ethanol into a reactor which contains a catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support.
Another aspect of the present invention relates to a butanol obtained using a heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support, wherein the vapor pressure of the butanol is of less than 1.53 kPa and the butanol has a purity of at least 96%.
The accompanying figures, which are incorporated into and constitute a part of this specification, illustrate one or more embodiments of the disclosure and, together with the detailed description, serve to explain the principles and implementations of the invention.
The present invention relates to a titanium-based bimetallic heterogeneous catalyst with enhanced selectivity, activity, and stability for the more efficient production of butanol.
For the purpose of this patent application the term “butanol” refers to n-butanol, butyl alcohol or 1-butanol, which corresponds to the following chemical structure (I):
Also, the term “titanium dioxide” refers to the chemical formulae TiO2, and both the term “titanium dioxide” or the chemical formulae TiO2, could be used indistinctively.
On the other hand, the term “ethanol” includes ethanol produced by any known or future method, including ethanol obtained from biological material processing, which is also known as “bioethanol”, and ethanol obtained from oil derivates.
Thus, a first aspect of the present invention relates to a titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support.
In an embodiment of the present invention, the cobalt cations are cobalt (III). The inclusion of cobalt cations within the titanium dioxide support was found to enrich oxygen vacancy numbers on the support surface to accommodate metallic nanoparticles, which yielded in part the improved catalytic activity, thermal stability and oxygen mobility during aldol condensation. Preferably, the cobalt cations are absorbed into the surface of the support of titanium dioxide.
In another embodiment of the present invention, the transition metal nanoparticles are selected from gold (Au) nanoparticles, cobalt (Co) nanoparticles or a mixture thereof. Preferably the transition metal nanoparticles are a mixture of gold and cobalt nanoparticles, which forms a nanoalloy (Au—Co) in the surface of the titanium dioxide support.
Also, preferably the transition metal nanoparticles are from approximately 0.8 to 1.2% of the total weight of the titanium-based bimetallic heterogeneous catalyst, and more preferably the transition metal nanoparticles are approximately 1.0% of the total weight of the titanium-based bimetallic heterogeneous catalyst.
Preferably the titanium dioxide support doped with cobalt cations is of a controlled geometry and low coordination. Also preferably the average crystal size of the titanium dioxide support doped with cobalt cations is lower than the average particle size of the common titanium dioxide, and more preferably the crystal size is approximately between 16.8 nm and 17.8 nm. This decrease in the crystal size provokes an increase in the surface area, which it is also related to the increase of oxygen vacancies.
Additionally, the specific surface area of the titanium dioxide support doped with cobalt cations is higher than the specific surface area of the common titanium dioxide, and more preferably the specific area is approximately between 64 m2/g and 66 m2/g. This increase in the specific surface area is also related to the incorporation of the cobalt cations into the crystalline structure and the resulting formation of oxygen on the support surface.
Also, the present invention relates to a manufacturing process of a titanium-based bimetallic heterogeneous catalyst comprising the following steps: a) mixing titanium dioxide with a cobalt salt to obtain a support of titanium dioxide doped with cobalt cations; b) adding to the support of titanium dioxide doped with cobalt cations at least one transition metal salt solution to obtain a titanium-based bimetallic heterogeneous catalyst comprising titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support.
In an embodiment of the present invention, the step of mixing titanium dioxide with a cobalt salt to obtain a support of titanium dioxide doped with cobalt cations is preferably carried out by a wet precipitation process, and more preferably the wet precipitation process is carried on in deionized water. After mixing the titanium dioxide with the cobalt salt, the mixture preferably is calcinated, and more preferably it is calcinated at 600° C.
The titanium dioxide used in the manufacturing process could be any common titanium dioxide commercially available. Preferably the titanium dioxide is selected from a titanium dioxide with at least 80% of anatase crystalline phase.
The cobalt salt could be selected from any ionic compound containing cobalt. Preferably, the cobalt salt is a cobalt nitrate.
In another embodiment of the present invention, the step of adding to the support of titanium dioxide doped with cobalt cations at least one transition metal salt solution is preferably is carried out by a wet precipitation process, and more preferably the wet precipitation process is carried on in deionized water.
Preferably, two transition metal salt solutions are added to the support of titanium dioxide doped with cobalt cations. More preferably, a first transition metal salt solution is added to the support of titanium dioxide doped with cobalt cations to impregnate the support with nanoparticles of a first transition metal, and subsequently a second transition metal salt solution is added to the support of titanium dioxide doped with cobalt cations to impregnate the support with nanoparticles of a second transition metal. Each transition metal salt solution could be selected from a gold (Au) salt solution or a cobalt (Co) salt solution. More preferably, the gold salt solution is HAuCl4 and the cobalt salt solution is Co(NO3)2. In a preferred embodiment of the present invention, after adding the first metal transition salt solution the mixture is dried and calcinated. Then, the second metal transition salt solution is added and the mixture is dried and calcinated again.
One of the advantages of the manufacturing process is that it does not use urea or sodium hydroxide as a precipitating agent since it only uses water as precipitating agent, which results in an easier and simpler process.
Other aspect of the present invention relates to a method for the production of butanol comprising the step of introducing a feed of ethanol into a reactor which contains a catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support.
In an embodiment of the present invention, the feed of ethanol is bioethanol which is preferably obtained by sugar fermentation process, wherein the main sources of the sugar required to produce ethanol come from renewable waste materials. These renewable waste materials could be derived from corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants. Also, it is preferred that the bioethanol obtained by sugar fermentation process has been purified to achieve at least 96% of purity.
Preferably, the feed of ethanol has a flow rate between 0.01 and 0.03 L/min at the entrance of the reactor, more preferably the feed of ethanol has a flow rate of 0.02 L/min at the entrance of the reactor.
In another embodiment of the present invention, the reactor is a “U” shape quartz reactor with a porous plate. Also, it is preferred that the reactor provides a temperature ramp between 2 and 4° C./minute, more preferably the reactor provides a temperature ramp of 3° C./minute.
Another aspect of the present invention relates to a butanol obtained using a heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support, wherein the vapor pressure of the butanol is of less than 1.53 kPa and a purity of at least 96%.
Hereinafter, the present invention will be described in further detail with reference to examples, but the scope of the present invention is not limited to these examples.
An essay was performed to obtain a support of titanium dioxide doped with cobalt cations according to the present invention. For this purpose, 3 g of TiO2 P25 (>99.5%, Aldrich, BET 35-65 m2·g−1) were suspended in 150 mL of deionized water and homogenized for 30 min. At room temperature and under constant stirring, 200 μL of Cobalt Nitrate Hexahydrate (99.999%, Aldrich) is added dropwise every 15 min for 10 hours and until a final volume of 6 mL is completed. Then the mixture is homogenized at 60° C. for 1 hour. The mixture is placed in a reflux system and heated at 130° C. with constant stirring for 2 hours. The sample is allowed to age at room temperature for 120 hours, without stirring. When the material has lost all the water and acquires a metallic appearance, it is crushed in a mortar and calcined in air flow for 2 hours (temperature ramp 5K min′) at 600° C. to obtain the support of titanium dioxide doped with cobalt cations (Co—TiO2).
An essay was performed to impregnate the support of titanium dioxide doped with cobalt cations of Example 1 with gold nanoparticles according to the present invention.
The support of titanium dioxide doped with cobalt cations of Example 1 was dried at 100° C. for 12 hours in order to desorb any species that could have been adsorbed on its surface. Then, 1.215 mL (4.2×10−3 mol·L−1) of HAuCl4.3H2O (99.9%, Aldrich), as gold salt solution, was mixed in 20 mL of deionized water, and 0.3 g of the support of titanium dioxide doped with cobalt cations of Example 1 was added with stirring. The temperature of the suspension was increased to 80° C. and was kept under constant stirring and protection from light for 12 hours. In this manner, the slow precipitation of Au′ cations was allowed and a local and high increase in pH was avoided. After the 12 hours, the material was recovered by centrifugation, washed five times with 50 mL of deionized water and dried at 100° C. In this manner, the support of titanium dioxide doped with cobalt cations of Example 1 was impregnated with gold (Au) nanoparticles.
An essay was performed to impregnate the support of titanium dioxide doped with cobalt cations of Example 2 with cobalt nanoparticles, to form a nanoalloy (Au—Co) in its surface, and obtain a titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support according to the present invention.
The support of titanium dioxide doped with cobalt cations of Example 2 was dried at 100° C. for 12 hours in order to desorb any species that could have been adsorbed on its surface. Then, 4.05 mL (4.2×10−3 mol·L−1) of Co(NO3)2.6H2O (99.999%, Aldrich), as cobalt salt solution, was mixed in 20 mL of deionized water and homogenized for 15 min at room temperature. Under constant stirring 0.3 g of the support of titanium dioxide doped with cobalt cations of Example 2 was added. The temperature of the suspension was increased to 80° C. and was kept under constant stirring and protection from light for 12 hours. In this manner, the slow precipitation of Co′ cations was allowed and a local and high increase in pH was avoided. After the 12 hours, the material was recovered by decantation, washed five times with 50 mL of deionized water and dried at 100° C. The resulting material was calcined at 600° C. in air flow with a heating ramp of 5 K min−1, maintaining the final temperature for 3 hours. In order to activate the gold and cobalt nanoparticles, the material was treated in a flow of hydrogen at 300° C. for 2 hours with a temperature ramp of 5K min′. The support of titanium dioxide doped with cobalt cations of Example 2 was impregnated with 0.5% by weight of cobalt (Co) nanoparticles.
An essay was performed to analyse and compare the crystalline structure of commercial TiO2, the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2), the support of titanium dioxide doped with cobalt cations impregnated with gold nanoparticles (Modified-TiO2—Au) of Example 2, the support of titanium dioxide doped with cobalt cations impregnated with cobalt nanoparticles (Modified-TiO2—Co) prepared according to the process described in Examples 1 and 3, and the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3, by X-Ray diffraction.
It is important to preserve the crystalline anatase phase in each of the modification processes and nanoparticle doping, as this phase is relevant to the chemical and thermal stability of the catalyst. For this purpose, two methods of quantification of crystalline phases were used. The first is the RIR method, a semiquantitative method based on reference intensity coefficients and scale factors determined from the phases. The second is the Rietveld method, a highly reliable quantitative method, especially powerful for complex phase mixes that show strong peak overlap due to low concentration.
The commercial TiO2 used was 85.1% anatase and 14.9% rutile.
The intensity of the peaks at 2θ=25.3° and 27.4° were considered as IA and IR, to calculate the percentage of the anatase phase and rutile phase in each material. As can be seen in Table 1, the relationship between the percentage of anatase is maintained in a greater proportion than that of rutile, a slight decrease in the percentage of the anatase phase between the commercial TiO2 and the Modified TiO2—Au—Co (from 85.1 to 73.0%) confirms that the cation substitution occurred and that this is expected to increase in the number of oxygen vacancies on the surface.
Table 2 shows the calculation of the crystal size of commercial TiO2 and Modified-TiO2. In order to perform the crystal size calculation, the Scherrer equation was used. The crystal size of the commercial TiO2 was larger (19.8 nm) than that of the Modified-TiO2 (17.3 nm). The decrease in the crystal size is related to the increase in the surface area-volume, confirming the presence of oxygen vacancies available on the surface of the Modified-TiO2.
An essay was performed to analyse and compare the specific surface area (BET) and the porous size distribution (BJH) of commercial TiO2, the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2), and the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3.
In
In Table 3, the textural properties of the Commercial TiO2, Modified-TiO2 and Modified-TiO2—Au—Co are listed. The specific surface area of the Modified-TiO2 is greater (64.95 m2 g−1) than that of the Commercial TiO2 (56.87 m2 g−1). Both the pore diameter and the pore volume increases for the Modified-TiO2—Au—Co. This can be attributed to the incorporation of cobalt cations within the structure of TiO2 and the formation of oxygen vacancies.
An essay was performed to analyse and compare the temperature-programmed desorption (TPD) of commercial TiO2, the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2), the support of titanium dioxide doped with cobalt cations impregnated with gold nanoparticles (Modified-TiO2—Au) of Example 2, the support of titanium dioxide doped with cobalt cations impregnated with cobalt nanoparticles (Modified-TiO2—Co) prepared according to the process described in Examples 1 and 3, and the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3.
In
The results of the TPD analysis as shown in
An essay was performed to measure the particle size of the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3.
In
An essay was performed to assess the aldol condensation from ethanol to butanol using the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3, according to the present invention. Also, for the purpose of comparing catalytic performance, it was also assessed the aldol condensation from ethanol to butanol using commercial TiO2, the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2), a catalyst comprising a support of titanium dioxide doped with titanium (IV) cations (ModifiedTiIV—TiO2) according to the prior art, and a catalyst comprising a support of titanium dioxide doped with titanium (IV) cations and gold nanoparticles (ModifiedTiIV—TiO2—Au) according to the prior art.
For assessing Modified-TiO2—Au—Co, 150 mg of Modified-TiO2—Au—Co were weighed and sieved at 250-355 μm, the Modified-TiO2—Au—Co was compressed and inserted into a “U” shape quartz reactor with a porous catalytic bed. The reactor is coupled in its inflow to a 0.02 L/min ethanol feed system (previously obtained from biomass and reaching a degree of purity of 96% with selective polymer membranes) and subjected to a temperature ramp inside an electric furnace controlled with increments of 3° C. per minute. Outgoing gases were analyzed online with a gas chromatograph (Perkin Elmer Clarus 580) equipped with a flame ionization detector (FID). A TRB5MS capillary column (30 m, 0.25 mm) was used as the stationary phase. Component identification was performed using commercial standards and confirmed by GCMS (Shimadzu QP2010) using the same column and methodology as in the GCFID. Conversions were calculated from the ethanol concentration at the inlet and outlet of the reactor. The selectivity was calculated using the economy of the atom, relating the concentration between the desired product (butanol) and the concentration of all the identified reaction products (acetaldehyde, acetic acid, butanal, crotonaldehyde, crotyl alcohol, diethyl ether, ethyl acetate, ethylene, methane, 1-hexanol, 1-octanol, 1,3-butadiene, 2-ethylbutanol and 2-ethylhexanol) considering the carbon atoms of each component. Carbon balances were verified by comparing the total amount of carbon atoms at the inlet and outlet of the reactor, considering the identified products.
In this regard
On the other hand, tests of the ModifiedTiIV—TiO2—Au were performed under the same conditions, but with an injection of Hydrogen at the inlet of the catalytic reactor of 0.02 L/min (STP) (H2He). It is important to note that the injection of Hydrogen is used in this case because the ModifiedTiIV—TiO2—Au is not capable of promoting hydrogen to generate chemical balance, as in the case of the catalyst of the present invention, which does not require hydrogen feed since this catalyst is capable of promoting hydrogen and generating chemical balance. 150 mg of the ModifiedTiIV—TiO2—Au were weighed and sieved at 250-355 μm, the ModifiedTiIV—TiO2—Au is compressed and inserted into a “U” shape quartz reactor with a porous catalytic bed. The reactor is coupled in its inflow to a 0.02 L/min ethanol feed system (previously obtained from biomass and reaching a degree of purity of 96% with selective polymer membranes) and subjected to a temperature ramp inside an electric furnace controlled with increments of 3° C. per minute. Outgoing gases were analyzed online with a gas chromatograph (HP6890 Plus) equipped with a flame ionization detector (FID). A TRB5MS capillary column (30 m, 0.25 mm) was used as the stationary phase. Component identification was performed using commercial standards and confirmed by GCMS (Shimadzu QP2010) using the same column and methodology as in the GCFID. Conversions were calculated from the ethanol concentration at the inlet and outlet of the reactor. The selectivity was calculated using the economy of the atom, relating the concentration between the desired product (butanol) and the concentration of all the identified reaction products (acetaldehyde, acetic acid, butanal, crotonaldehyde, crotyl alcohol, diethyl ether, ethyl acetate, ethylene, methane, 1-hexanol, 1-octanol, 1,3-butadiene, 2-ethylbutanol and 2-ethylhexanol) considering the carbon atoms of each component. Carbon balances were verified by comparing the total amount of carbon atoms at the inlet and outlet of the reactor, considering the identified products. The “percent atom economy” was calculated as follows: % Atom Economy=(FW of atoms utilized/FW of all reactants)×100=97.98%.
In this regard
In Table 4 it is summarized the catalytic activity in the aldol condensation from ethanol to butanol at different temperatures.
The Modified-TiO2—Au—Co, according to the present invention, has the highest catalytic activity in the aldol condensation from ethanol to butanol.
An essay was performed to analyse and compare the magnetic properties of commercial TiO2, the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2), the support of titanium dioxide doped with cobalt cations impregnated with gold nanoparticles (Modified-TiO2—Au) of Example 2, the support of titanium dioxide doped with cobalt cations impregnated with cobalt nanoparticles (Modified-TiO2—Co) prepared according to the process described in Examples 1 and 3, and the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3. The magnetic properties were assessed using a vibrating sample magnetometer (VSM) and compared to a catalyst comprising a support of titanium dioxide doped with titanium (IV) cations and gold nanoparticles (ModifiedTiIV—TiO2—Au) according to the prior art.
In Table 5 it is summarized the magnetic properties of the different material that were assessed.
An essay was performed to analyse and compare the optic properties of commercial TiO2, the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2), the support of titanium dioxide doped with cobalt cations impregnated with gold nanoparticles (Modified-TiO2—Au) of Example 2, the support of titanium dioxide doped with cobalt cations impregnated with cobalt nanoparticles (Modified-TiO2—Co) prepared according to the process described in Examples 1 and 3, and the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3. The optic properties were assessed by surface plasmon resonance (SPR) in comparison with a catalyst comprising a support of titanium dioxide doped with titanium (IV) cations and gold nanoparticles (ModifiedTiIV—TiO2—Au) according to the prior art.
In
In Table 6 it is summarized the electromagnetic absorption of the different material that were assessed.
An essay was performed to assess the structural differences between commercial TiO2 and the support of titanium dioxide doped with cobalt cations of Example 1 (Modified-TiO2). This essay was performed using X-ray Photoelectron Spectroscopy (XPS).
The XPS analyses of the Ti 2p region after peak deconvolution and background removal for Commercial TiO2 and Modified-TiO2 are shown in
4Ti4++O2−→4Ti4++2e−/X+0.5O2
4Ti4++O2−→2Ti4++2Ti3++X+0.5O2
The “X” represents a vacant site originating from the removal of O2− from the TiO2 matrix. It can be concluded that an oxygen vacancy is generated together with two Ti3+ cations. Slight displacements of 1.5 eV are also observed in the main peaks of TiO2 in Modified-TiO2. From 457.3 eV (Ti 2p3/2) to 455.8 eV and from 463.2 eV (Ti 2p1/2) to 461.7 eV, due to the modification that takes place on the surface of the TiO2 matrix when the oxygen vacancies are generated.
Regarding the O 1s spectrum showed in
An essay was performed to assess the thermal stability of the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3 according to the present invention, in comparison with a catalyst comprising a support of titanium dioxide doped with titanium (IV) cations and gold nanoparticles (ModifiedTiIV—TiO2—Au) according to the prior art, by a thermogravimetric analysis (TGA).
Both Modified-TiO2—Au—Co and ModifiedTiIV—TiO2—Au were subjected to a temperature sweep of 25-1000° C. (10° C./min). In
Also in
An essay was performed to further assess the thermal stability of the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3 according to the present invention, in comparison with a catalyst comprising a support of titanium dioxide doped with titanium (IV) cations and gold nanoparticles (ModifiedTiIV—TiO2—Au) according to the prior art, by a thermogravimetric analysis (TGA) over 20 catalytic cycles under the same conditions.
In
Also in
An essay was performed to determine the vapor pressure and purity of the butanol obtained according to the process described in Example 8 during the aldol condensation from ethanol to butanol using the titanium-based bimetallic heterogeneous catalyst comprising a support of titanium dioxide doped with cobalt cations and transition metal nanoparticles impregnated in the support (Modified-TiO2—Au—Co) of Example 3, according to the present invention.
In this essay, the vapor pressure (Reid) of the butanol was measured according to the ASTM D323-15a method in the facilities of the Mexican Institute of Petroleum. In this regard, the reported vapor pressure of the butanol obtained using Modified-TiO2—Au—Co was 1.53 kPa, or 0.22 lb/plg2.
On the other hand, purity was measured using gas chromatography-mass spectrometry (GC-MS) in the facilities of the Mexican Institute of Petroleum. In this regard, the reported purity was of 98.98%.
In accordance with the foregoing, it shall be apparent to a person skilled in the art that the preferred embodiment of the titanium-based bimetallic heterogeneous catalyst, its manufacturing process and the method for the production of butanol using the same illustrated above is set forth for illustrative purposes only but not limited to the present invention, since a person skilled in the art can make numerous variations thereto, provided they are designed according to the principles of the present invention. In fact, the titanium-based bimetallic heterogeneous catalyst could be used as a catalyst in any chemical reaction involving aldol condensation.
Accordingly, the present invention includes all of the embodiments that a person skilled in the art can pose from the concepts contained in the present specification, in accordance with the following claims.
