Alcohol production method using surface reaction calcium carbonate catalyst

Abstract

The method of the present invention comprises the steps of: (a) providing a primary or secondary alcohol having at least one β-hydrogen; (b) providing a surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is prepared by reacting ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) with carbon dioxide and one or more of HO. + The reaction product with the ion donor is carbon dioxide, H3O + The surface-reacted calcium carbonate, formed in situ by an ion donor treatment and / or provided from an external source, has a surface-reacted calcium carbonate content of at least 15 m when measured using nitrogen and the BET method according to ISO 9277:2010. 2 / g, (c) vaporizing the alcohol, and (d) reacting the vaporized alcohol in the presence of surface-reacted calcium carbonate as a catalyst.

Description

[Technical field]

[0001] The present invention relates to a method for producing alcohols by Guerbet self-condensation in the gas phase. Furthermore, the present invention relates to the use of surface-reacted calcium carbonate as a catalyst for the Guerbet self-condensation in the gas phase. [Background technology]

[0002] The self-condensation of alcohols to dimeric or higher alcohols in the presence of a catalyst, also known in the art as the Guerbet reaction, is an attractive process for converting relatively simple and inexpensive alcohols into more valuable products.

[0003] Different homogeneous catalysts, heterogeneous catalysts, or combinations thereof are known in the art to catalyze the Guerbet reaction. For example, it is known that the Guerbet reaction can be catalyzed by transition metal catalysts based on palladium, platinum, iridium, copper, nickel, ruthenium, cobalt, etc. A general disadvantage of transition metal catalysts is that they are usually relatively expensive and, in some cases, involve difficult synthesis. In addition, known catalyst systems for the Guerbet reaction often require a cocatalyst to work efficiently, which can complicate reaction control. Furthermore, homogeneous catalysts are only applicable in liquid phase reactions. However, in many cases, gas phase reactions are preferred over liquid phase reactions, for example, to reduce waste or to simplify purification of the product stream.

[0004] Heterogeneous alkaline earth catalysts are useful for gas-phase or vapor-phase Guerbet reactions and can avoid some of the above-mentioned drawbacks associated with other catalytic systems. However, known heterogeneous alkaline earth metal catalysts often provide fairly low conversions of alcohol substrates and are limited in terms of product selectivity and its yield. In addition, some known heterogeneous alkaline earth metal catalysts, such as hydroxylapatite (HAP) catalysts, must be prepared by a relatively complicated sol-gel method, which can make them quite expensive and their application unattractive from a business point of view.

[0005] It is an object of the present invention to provide an alternative or improved process for preparing alcohols by Guerbet self-condensation reaction in the gas phase. It is another object of the present invention to provide an alternative or improved catalyst useful for Guerbet self-condensation reaction in the gas phase. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the invention is achieved by the methods and uses according to the independent claims. [Means for solving the problem]

[0007] In one embodiment, the present invention provides a method for preparing alcohols by Guerbet self-condensation reaction in the gas phase.

[0008] The method according to the invention comprises the following steps: (a) providing a primary or secondary alcohol having at least one β-hydrogen; (b) providing a surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a mixture of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) and carbon dioxide and one or more of HO. + The reaction product with the ion donor is carbon dioxide, H3O +The surface-reacted calcium carbonate, formed in situ by ion donor treatment and / or provided from an external source, has a surface-reacted calcium carbonate content of at least 15 m when measured using nitrogen and the BET method according to ISO 9277:2010. 2 / g specific surface area; (c) vaporizing the alcohol provided in step (a); (d) reacting the vaporized alcohol obtained in step (c) in the presence of the surface-reacted calcium carbonate provided in step (b) as a catalyst.

[0009] In another aspect, the present invention relates to the use of surface-reacted calcium carbonate as a catalyst for the Guerbet self-condensation reaction in the gas phase, where the surface-reacted calcium carbonate is a mixture of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) with carbon dioxide and one or more HO + The reaction product with the ion donor is carbon dioxide, H3O + The surface-reacted calcium carbonate, formed in situ by ion donor treatment and / or provided from an external source, has a surface-reacted calcium carbonate content of at least 15 m when measured using nitrogen and the BET method according to ISO 9277:2010. 2 / g.

[0010] The inventors have unexpectedly found that the specific surface-reacted calcium carbonates described herein are useful as catalysts for the self-condensation of alcohols in the gas phase. The process using the specific surface-reacted calcium carbonates as catalysts provides comparable or better results (conversion, selectivity, stability) compared to known alkaline earth metal catalysts for the same purpose.

[0011] The process does not require a co-catalyst. Furthermore, the surface-reacted calcium carbonate can be obtained by surface-reacting ground natural or precipitated calcium carbonate, as described herein, and therefore can be obtained from readily available and relatively inexpensive starting materials.

[0012] Preferred aspects of the invention are defined in the dependent claims.

[0013] According to one embodiment of the invention, the primary or secondary alcohol provided in step (a) has a boiling point below 200°C, preferably below 175°C, more preferably below 145°C, and most preferably below 125°C.

[0014] According to one embodiment of the invention, the alcohol provided in step (a) is a primary alcohol.

[0015] According to one embodiment of the present invention, the primary or secondary alcohol provided in step (a) is a branched or linear C2-C 12 The primary or secondary alcohol having an alkyl chain, preferably a branched or linear C2-C6 alkyl chain, or the primary or secondary alcohol provided in step (a) is selected from the group consisting of ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-propanol, 2-methyl-1-propanol, 2-butanol, 3-methyl-2-butanol, 2-butanol, and 3-pentanol.

[0016] According to one embodiment of the present invention, the surface-reacted calcium carbonate provided in step (b) has a volume median particle size (d) of 1.0 to 75 μm, preferably 2 to 50 μm, more preferably 3 to 40 μm, even more preferably 4 to 30 μm, and most preferably 5 to 15 μm. 50 ), and / or a top cut (d 98 ).

[0017] According to one embodiment of the present invention, the surface-reacted calcium carbonate provided in step (b) has a viscosity of 15 to 200 m, as measured by the BET method. 2 / g, preferably 27 to 180 m 2 / g, more preferably 30 to 180m 2 / g, and even more preferably 45 to 180 m 2 / g, most preferably 120 to 180m 2 / g specific surface area (BET).

[0018] According to one embodiment of the present invention, the surface-reacted calcium carbonate provided in step (b) has a porosity of 0.10 to 2.3 cm as calculated from mercury porosimetry measurements. 3 / g, more preferably 0.20 to 2.0 cm 3 / g, and even more preferably 0.40 to 1.8 cm 3 / g, most preferably 0.70 to 1.6 cm 3 / g.

[0019] According to one aspect of the present invention, one or more HO + The ion donor is selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, citric acid, oxalic acid, acid salts, acetic acid, formic acid, and mixtures thereof, preferably hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, H2PO4 - and the corresponding cation, e.g. Li + , Na + Or K + , HPO4 2- and at least partially neutralized by the corresponding cation, e.g. Li + , Na + , K + , Mg 2+ , or Ca 2+ and mixtures thereof, more preferably selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, or mixtures thereof, and most preferably one or more of HO. + The ion donor is phosphoric acid.

[0020] According to one embodiment of the present invention, the surface-reacted calcium carbonate is a mixture of ground natural calcium carbonate (GNCC) and carbon dioxide and one or more of HO. + reaction product with an ion donor, where one or more HO +The ion donor is phosphoric acid, and carbon dioxide is HO + It is formed in situ by treatment with an ion donor.

[0021] According to one embodiment of the present invention, the surface-reacted calcium carbonate provided in step (b) has a total number of base sites of 0.01-0.6 mmol / g, preferably 0.05-0.5 mmol / g, more preferably 0.10-0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed carbon dioxide desorption and / or a total number of acid sites of 0.01-0.6 mmol / g, preferably 0.05-0.5 mmol / g, more preferably 0.10-0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed carbon dioxide desorption and determined by temperature programmed desorption with ammonia.

[0022] According to one embodiment of the present invention, the surface-reacted calcium carbonate is dried prior to step (d) at a temperature in the range of 100-500°C, preferably 300-475°C, and / or the surface-reacted calcium carbonate used in step (d) has a total residual moisture content of 0.01 wt.-% to 0.75 wt.-%, preferably 0.02 wt.-% to 0.5 wt.-%, based on the total dry weight of the surface-reacted calcium carbonate.

[0023] According to one embodiment of the present invention, the vaporized alcohol obtained in step (c) is present in the gas feed stream in an amount of at least 2% by volume, preferably 10-80% by volume, more preferably 10-55% by volume, most preferably 10-40% by volume, and / or the vaporized alcohol obtained in step (c) is mixed with a carrier gas selected from the group consisting of helium, nitrogen, argon, and mixtures thereof, preferably nitrogen.

[0024] According to one embodiment of the present invention, step (d) is carried out at a reaction temperature in the range of 150-500°C, preferably 150-475°C, more preferably 250-475°C, and most preferably 375-475°C.

[0025] According to one embodiment of the present invention, the surface-reacted calcium carbonate is used in the Guerbet self-condensation reaction of primary or secondary alcohols as defined herein.

[0026] In the context of the present invention, the following terms have the following meanings.

[0027] "β-hydrogen" is the hydrogen atom attached to the carbon atom in the β position to the hydroxy group (-OH) of the alcohol provided in step (a) of the process according to the invention (or the alcohol provided for use according to the invention). The carbon atom in the β position to the hydroxy group refers to the carbon atom that is directly attached to the carbon atom (α position) that is attached to the hydroxy group. In the case of ethanol, the β position can be depicted as follows: [ka]

[0028] A "Guerbet self-condensation reaction" is a condensation reaction of two identical alcohol molecules (e.g., two molecules of the same primary or secondary alcohol) with the release of one water molecule, which results in an alcohol product containing the sum of the carbon atoms of the two alcohol molecules. For example, the Guerbet self-condensation reaction of ethanol (a C2 alcohol) results in n-butanol (a C4 alcohol).

[0029] The Guerbet self-condensation reaction of alcohols is well known in the art. It is currently believed in the art that the reaction proceeds stepwise, in that two molecules of the same primary or secondary alcohol base are first dehydrogenated to provide two aldehydes or ketones, respectively, which then undergo aldol condensation to form an α,β-unsaturated aldehyde or ketone. The α,β-unsaturated aldehyde or ketone is then fully hydrogenated to provide the final alcohol product. The current understanding in the art of the reaction mechanism of Guerbet self-condensation is included herein for illustrative purposes only and should not be interpreted as limiting the method according to the present invention in any way.

[0030] As will be readily understood by one of ordinary skill in the art, a "primary or secondary alcohol having at least one β-hydrogen" as defined herein can be dehydrogenated to an enolizable aldehyde or ketone, which can then react in an aldol condensation.

[0031] A "gas phase reaction" or "reaction in the gas phase" should be understood as a chemical reaction involving a gaseous reactant, e.g., a primary or secondary alcohol as defined herein, optionally diluted in a non-reactive carrier gas (e.g., nitrogen).

[0032] The "surface-reacted calcium carbonate" according to the present invention is a process for the preparation of natural ground calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) by the addition of carbon dioxide and one or more HO. + The reaction product is treated with an ion donor, where carbon dioxide is H3O + It is formed in situ by ion donor treatment. + The ion donor is a Bronsted acid and / or an acid salt. The terms "natural ground calcium carbonate" and "ground natural calcium carbonate" are used interchangeably herein and refer to the same material.

[0033] Throughout this specification, the term "specific surface area" ("SSA", m 2 / g) refers to the specific surface area determined by using the BET method (with nitrogen as the adsorption gas) according to ISO 9277:2010.

[0034] The "particle size" of the surface-reacted calcium carbonate in this specification is determined by the volume-based particle size distribution d x (volume), where the value d x (Volume) is x volume percent d x (volume) represents a diameter that is less than the diameter of the particle. For example, d20(volume) means that 20% by volume of all particles are smaller than that diameter. Therefore, d50 The (volume) value is the volume median particle size, i.e., the particle size below which 50% by volume of all particles are smaller, and is called the volumetric top cut d 98 The volumetric value is the particle size below which 98% of all particles by volume are smaller. x The volume can be determined by laser diffraction.

[0035] Volume median particle size d 50 was evaluated using a Malvern Mastersizer 3000 laser diffraction instrument. 50 Or d 98 The values ​​indicate the diameter value such that 50% or 98% by volume of the particles have a diameter less than this value, respectively. The raw data obtained by the measurements are analyzed using Mie theory, assuming a particle refractive index of 1.57 and an absorptivity of 0.005.

[0036] For purposes of the present invention, "porosity" or "pore volume" refers to the intraparticle specific pore volume.

[0037] In the context of the present invention, the term "pores" is understood to describe the spaces found between and / or within particles, i.e. the spaces formed by particles when they are packed together in nearest contact conditions, e.g. in a powder or compact (interparticle porosity), and / or the void spaces within porous particles (intraparticle porosity), which when saturated with liquid allow the passage of liquid under pressure and / or support the absorption of a surface-wetting liquid.

[0038] Specific pore volume is measured using mercury intrusion porosimetry measurements using a Micromeritics Autopore V 9620 mercury porosimeter with a maximum applied pressure of 414 MPa (60,000 psi) mercury pressure, corresponding to a Laplace throat diameter of 0.004 μm. Equilibration times used at each pressure step are 20 seconds. Sample material is enclosed in three 3 cm powder penetrometers for analysis. Data are corrected for mercury compression, penetrometer expansion, and sample material elastic compression using the software Pore-Comp (Gane, P.A.C., Kettle, J.P., Matthews, G.P. and Ridgway, C.J., "Void Space Structure of Compressible Polymer Spheres and Consolidated Calcium Carbonate Paper-Coating Formulations", Industrial and Engineering Chemistry Research, 1996, 35(5), 1753-1764).

[0039] The total pore volume seen in the cumulative indentation data is separated into two regions with indentation data from 214 μm down to about 1-4 μm, indicating a strong contribution from the coarse grain packing of the sample between any aggregate structures. Below these diameters there is fine interparticle packing of the particles themselves. If they also have intraparticle porosity, this region appears bimodal and we define the specific intraparticle pore volume by taking the specific pore volume indented by mercury to be the pores finer than the mode inflection point, i.e., the bimodal inflection point. The sum of these three regions gives the total pore volume of the powder, but is strongly dependent on the settling of the powder at the coarse pore end of the compaction / distribution of the original sample.

[0040] Taking the first derivative of the cumulative intrusion curve reveals the pore size distribution based on the equivalent Laplace diameter, which inevitably includes pore shielding. The derivative curve clearly shows the coarse aggregate pore structure region, the interparticle pore region, and the intraparticle pore region, if present. Knowing the range of intraparticle pore diameters, it is possible to subtract the remaining interparticle and interagglomerate pore volumes from the total pore volume to derive the desired pore volume of the internal pores alone, in terms of pore volume per unit mass (specific pore volume). Of course, the same principle of subtraction applies to isolate any of the other pore size regions of interest.

[0041] A "dry" material in the sense of the present invention (e.g. dry surface-reacted calcium carbonate) has, unless stated otherwise, a total or residual moisture content of 5.0% by weight or less, preferably 0.75% by weight or less, more preferably 0.5% by weight or less, even more preferably 0.2% by weight or less and most preferably 0.02 to 0.07% by weight, based on the total weight of the dry material.

[0042] "Total number of basic sites" is a measure of the basicity of a solid material and is represented by the total molar amount of carbon dioxide that can be adsorbed on the basic sites of a particular amount of solid material, as determined by temperature programmed desorption with carbon dioxide, as described herein.

[0043] "Total number of acid sites" is a measure of the acidity of a solid material and is represented by the total molar amount of ammonia that can be adsorbed on the acid sites of a particular amount of solid material, as determined by temperature programmed desorption with ammonia, as described herein.

[0044] When the term "comprising" is used in the present specification and claims, it does not exclude other unspecified elements of major or minor functional importance. For the purposes of the present invention, the terms "consisting essentially of" and "consisting of" are considered to be specific embodiments of the term "comprising". Hereinafter, when a group is defined to comprise at least a certain number of embodiments, this is also to be understood as disclosing a group that optionally consists essentially of or consists of only these embodiments.

[0045] Whenever the terms "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above.

[0046] When referring to a singular noun, e.g. "a", "an" or "the", an indefinite or definite article is used, which includes the plural of that noun, unless something else is specifically stated.

[0047] Terms such as "available" or "definable" and "obtained" or "defined" are used interchangeably. This means, for example, that unless the context clearly dictates otherwise, the term "obtained" is not meant to indicate that an embodiment must be obtained by, for example, the sequence of steps that modify the term "obtained," even though such a limited understanding is necessarily included by the terms "obtained" or "defined" as preferred embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] Methods of the Invention One aspect of the present invention relates to a method for preparing alcohols by Guerbet self-condensation reaction in the vapor phase.

[0049] The method comprises the steps of: (a) providing a primary or secondary alcohol having at least one β-hydrogen; (b) providing a surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a mixture of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) and carbon dioxide and one or more of HO. + The reaction product with the ion donor is carbon dioxide, H3O + The calcium carbonate formed in situ by ion donor treatment and / or provided from an external source and surface-reacted has a surface roughness of at least 15 m when measured using nitrogen and the BET method according to ISO 9277:2010. 2 / g specific surface area; (c) vaporizing the alcohol provided in step (a); (d) reacting the vaporized alcohol obtained in step (c) in the presence of the surface-reacted calcium carbonate provided in step (b) as a catalyst.

[0050] 《Process (a)》 The method includes the step (a) of providing a primary or secondary alcohol having at least one β-hydrogen.

[0051] A primary or secondary alcohol has at least one β-hydrogen. As will be appreciated by those skilled in the art, the total number of β-hydrogens depends on the structure of the alcohol provided in step (a). When a primary alcohol is provided in step (a), the alcohol can have one to three β-hydrogens depending on the substitution pattern on the β-carbon atom of the alcohol. For example, ethanol has three β-hydrogens, n-propanol has two β-hydrogens, and 2-methyl-1-propanol has one β-hydrogen. In a preferred embodiment, the alcohol is a primary alcohol having two or three β-hydrogens.

[0052] When a secondary alcohol is provided in step (a), the alcohol has two β-carbon atoms and can therefore have from 1 to 6 β-hydrogens (depending on the substituents on the β-carbon atom). In a preferred embodiment, the alcohol is a secondary alcohol having at least one β-carbon atom with 2 or 3 β-hydrogens.

[0053] According to one preferred embodiment, the primary or secondary alcohol provided in step (a) is an alcohol that does not essentially decompose (or does not decompose) upon evaporation.

[0054] The primary or secondary alcohol may have a predetermined boiling point. For example, the alcohol may have a boiling point below 300°C, for example in the range of 60 to 300°C. The boiling point of the alcohol is preferably below 200°C, preferably below 175°C, more preferably below 145°C, and most preferably below 125°C. The boiling point of the primary or secondary alcohol is particularly preferably in the range of 60 to 145°C or in the range of 60 to 125°C.

[0055] According to a preferred embodiment, the alcohol provided in step (a) is a primary alcohol having a boiling point below 200°C (e.g., in the range of 60 to 200°C), preferably below 175°C, more preferably below 145°C, and most preferably below 125°C.

[0056] The alcohol can be a primary or secondary alcohol. In one embodiment, the alcohol is a secondary alcohol. In another embodiment, the alcohol is a primary alcohol. Preferably, the alcohol is a primary alcohol.

[0057] The primary or secondary alcohol may be an alcohol having a branched alkyl chain (e.g., 2-methyl-1-propanol, 3-methyl-2-butanol), a straight alkyl chain (e.g., ethanol, n-propanol, n-butanol, n-pentanol, 2-propanol, 2-butanol), or a cyclic alkyl chain (e.g., cyclopentanol). The primary or secondary alcohol may be an alcohol having a branched alkyl chain (e.g., 2-methyl-1-propanol, 3-methyl-2-butanol), a straight alkyl chain (e.g., ethanol, n-propanol, n-butanol, n-pentanol, 2-propanol, 2-butanol), or a cyclic alkyl chain.

[0058] Preferably, the primary or secondary alcohol is a branched C2-C 12 Alkyl chain, more preferably a branched C2-C6 alkyl chain, or a linear C2-C 12 It is preferably an alcohol having an alkyl chain, more preferably a linear C2 to C6 alkyl chain.

[0059] In a preferred embodiment, the primary or secondary alcohol has a linear alkyl chain. In another preferred embodiment, the alcohol provided in step (a) has a linear alkyl chain, preferably a linear C2-C 12 It is preferably a primary alcohol having an alkyl chain, more preferably a C2-C6 alkyl chain.

[0060] According to a preferred embodiment, the alcohol provided in step (a) is selected from the group consisting of ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-propanol, 2-methyl-1-propanol, 2-butanol, 3-methyl-2-butanol, 2-butanol and 3-pentanol, preferably selected from the group consisting of ethanol, n-propanol, n-butanol, 2-propanol, 2-butanol and 2-pentanol.

[0061] In one particular embodiment, the alcohol provided in step (a) is ethanol.

[0062] 《Process (b)》 In step (b) of the process according to the invention, a surface-reacted calcium carbonate is provided. The surface-reacted calcium carbonate is prepared by reacting ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) with carbon dioxide and one or more HO. + The carbon dioxide is a reaction product with an ion donor, where HO + The specific surface area of ​​the surface-reacted calcium carbonate is at least 15 m2, as measured using nitrogen and the BET method according to ISO 9277:2010. 2 / g.

[0063] In a preferred embodiment of the present invention, the surface-reacted calcium carbonate is obtained by a process comprising the steps of: (a) providing a suspension of natural or precipitated calcium carbonate, (b) adding to the suspension of step (a) at least one acid having a pKa value of 0 or less at 20° C. or having a pKa value of 0 to 2.5 at 20° C., and (c) treating the suspension of step (a) with carbon dioxide before, during or after step (b). According to another embodiment, the surface-reacted calcium carbonate is provided by a process comprising the steps of: (A) providing a natural or precipitated calcium carbonate, (B) providing at least one water-soluble acid, (C) providing gaseous CO2, (D) contacting the natural or precipitated calcium carbonate of step (A) with at least one acid of step (B) and with CO2 of step (C). This method is characterized in that: (i) the at least one acid of step (B) has a pKa greater than 2.5 and less than 7 at 20° C., associated with the ionization of its first available hydrogen, and a corresponding anion is formed upon loss of this first available hydrogen capable of forming a water-soluble calcium salt, and (ii) after contacting the at least one acid with the natural or precipitated calcium carbonate, additionally providing at least one water-soluble salt, wherein the at least one water-soluble salt, when a hydrogen-containing salt, has a pKa greater than 7 at 20° C., associated with the ionization of its first available hydrogen, and an anion of the at least one water-soluble salt is capable of forming a water-soluble calcium salt.

[0064] "Natural ground calcium carbonate" (GNCC) is preferably selected from calcium carbonate-containing minerals selected from the group including marble, chalk, limestone, and mixtures thereof. Natural calcium carbonate may contain further natural components, such as aluminosilicates.

[0065] In general, the grinding of natural ground calcium carbonate can be a dry or wet grinding process and can be carried out using any conventional grinding equipment, for example under conditions in which grinding mainly occurs by collision with a second object. Here, any conventional grinding equipment can include one or more of ball mills, rod mills, vibratory mills, roll grinders, centrifugal impact mills, vertical bead mills, attrition mills, pin mills, hammer mills, crushers, shredders, declampers, knife cutters, or other such equipment known to those skilled in the art. If the calcium carbonate-containing mineral material comprises a wet-ground calcium carbonate-containing mineral material, the grinding process can be carried out under conditions in which autogenous grinding occurs and / or by horizontal ball mill grinding and / or by other such methods known to those skilled in the art. The wet-processed ground calcium carbonate-containing mineral material thus obtained can be washed and dewatered by known methods, for example by agglomeration, filtration or forced evaporation before drying. A subsequent drying step (if necessary) can be carried out in a single step, for example by spray drying, or in at least two steps. It is also common for such mineral materials to be subjected to beneficial processes to remove impurities, such as flotation, bleaching or magnetic separation processes.

[0066] In the context of the present invention, "precipitated calcium carbonate" (PCC) is a synthetic material generally obtained by reaction of carbon dioxide with calcium hydroxide in an aqueous environment and subsequent precipitation, or by precipitation of calcium and carbonate ions, e.g., CaCl2 and Na2CO3, from a solution. Further possible methods for producing PCC are the lime-soda process, or the Solvay process, in which PCC is a by-product of ammonia production. Precipitated calcium carbonate exists in three main crystalline forms: calcite, aragonite, and vaterite, and for each of these crystalline forms, many different polymorphs (crystalline phases) exist. Calcite has a trigonal structure with typical crystalline phases such as rhombohedral (S-PCC), rhombohedral (R-PCC), hexagonal prismatic, pinacoidal, colloidal (C-PCC), cubic, and prismatic (P-PCC). Aragonite is an orthorhombic structure with a typical crystalline phase of twinned hexagonal columnar crystals, and also a variety of thin elongated prisms, curved blades, steep pyramidal, chisel crystals, branching dendrites, and coral-like or vermiform morphologies. Vaterite belongs to the hexagonal crystal system. The resulting PCC slurry can be mechanically dewatered and dried.

[0067] According to one embodiment of the invention, the precipitated calcium carbonate is a precipitated calcium carbonate, preferably comprising aragonitic, vateritic or calcitic mineral crystal forms or mixtures thereof.

[0068] Precipitated calcium carbonate is a mixture of carbon dioxide and at least one HO + Prior to treatment with the ion donor, it may be ground by the same means used to grind the natural calcium carbonate described above.

[0069] According to one aspect of the invention, the natural or precipitated calcium carbonate has a mass median particle size d of 0.05 to 10.0 μm, preferably 0.2 to 5.0 μm, more preferably 0.4 to 3.0 μm, most preferably 0.6 to 1.2 μm, in particular 0.7 μm. 50According to a further aspect of the invention, the natural or precipitated calcium carbonate is in the form of particles having a top cut particle size d of 0.15 to 55 μm, preferably 1 to 40 μm, more preferably 2 to 25 μm, most preferably 3 to 15 μm, in particular 4 μm. 98 The compound is in the form of particles having the formula:

[0070] The natural and / or precipitated calcium carbonate can be used in dry form or suspended in water. Preferably, the corresponding slurry has a content of natural or precipitated calcium carbonate in the range of 1% to 90% by weight, more preferably 3% to 60% by weight, even more preferably 5% to 40% by weight, most preferably 10% to 25% by weight, based on the weight of the slurry.

[0071] One or more H3O used for the preparation of surface-reacted calcium carbonate + The ion donor is HO under the preparation conditions. + The acid may be any strong, moderately strong, or weak acid that produces ions, or a mixture thereof. According to the present invention, at least one HO + The ion donor is HO under the preparation conditions. + It may be an acid salt which produces ions.

[0072] According to one embodiment, at least one HO + The ion donor is a strong acid with a pKa at 20° C. of 0 or less.

[0073] According to another embodiment, at least one HO + The ion donor is a moderately strong acid having a pKa of 0 to 2.5 at 20° C. If the pKa at 20° C. is 0 or less, the acid is preferably selected from sulfuric acid, hydrochloric acid, or a mixture thereof. If the pKa at 20° C. is 0 to 2.5, HO + The ion donor is preferably selected from H2SO3, H3PO4, oxalic acid, or mixtures thereof. At least one H3O + The ion donor may also be the corresponding cation, e.g. Li + , Na+ Or K + , or HPO4 2- and at least partially neutralized by the corresponding cation, e.g. Li + , Na + ,K + , Mg 2+ or Ca 2+ at least partially neutralized by acid salts, e.g. HSO4 - or H2PO4 - At least one H3O + The ion donor may be a mixture of one or more acids and one or more acid salts.

[0074] According to yet another embodiment, at least one HO +The ion donor is a weak acid having a pKa greater than 2.5 and less than 7, when measured at 20° C., in association with the ionization of the first available hydrogen, and a corresponding anion capable of forming a water-soluble calcium salt. Then, at least one water-soluble salt is further provided, where the at least one water-soluble salt, in the case of a hydrogen-containing salt, has a pKa greater than 7, when measured at 20° C., in association with the ionization of the first available hydrogen, and the anion salt thereof is capable of forming a water-insoluble calcium salt. According to a preferred embodiment, the weak acid has a pKa value greater than 2.5 to 5, at 20° C., more preferably the weak acid is selected from the group consisting of acetic acid, formic acid, propanoic acid, and mixtures thereof. Exemplary cations of the water-soluble salts are selected from the group consisting of potassium, sodium, lithium, and mixtures thereof. In a more preferred embodiment, the cation is sodium or potassium. Exemplary anions of the water-soluble salts are selected from the group consisting of phosphate, dihydrogen phosphate, monohydrogen phosphate, oxalate, silicate, mixtures thereof, and hydrates thereof. In a more preferred embodiment, the anion is selected from the group consisting of phosphate, dihydrogen phosphate, monohydrogen phosphate, mixtures thereof, and hydrates thereof. In a most preferred embodiment, the anion is selected from the group consisting of dihydrate phosphoric acid, monohydrate phosphoric acid, mixtures thereof, and hydrates thereof. The addition of the water-soluble salt can be carried out dropwise or in one step. In the case of dropwise addition, the addition is preferably carried out in a time period of 10 minutes or less. It is more preferred to add the salt in one step.

[0075] According to one embodiment of the present invention, at least one HO + The ion donor is selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, citric acid, oxalic acid, acetic acid, formic acid, and mixtures thereof. Preferably, at least one HO + Ion donors include hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, and H2PO4. - and the corresponding cation, e.g. Li + , Na + Or K+ , HPO4 2- and at least partially neutralized by the corresponding cation, e.g. Li + , Na + ,K + , Mg 2+ , or Ca 2+ and mixtures thereof, more preferably at least one HO + The ion donor is selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, or mixtures thereof, and most preferably at least one HO + The ion donor is phosphoric acid.

[0076] One or more H3O + The ion donor can be added to the suspension as a concentrated solution or as a more dilute solution. + The molar ratio of the ion donor to the natural or precipitated calcium carbonate is from 0.01 to 4, more preferably from 0.02 to 2, even more preferably from 0.05 to 1, and most preferably from 0.1 to 0.58.

[0077] Alternatively, H3O + An ion donor may also be added to the water before the natural or precipitated calcium carbonate is suspended.

[0078] In the next step, the natural or precipitated calcium carbonate is treated with carbon dioxide. A strong acid, such as sulfuric or hydrochloric acid, is used to remove the HO of the natural or precipitated calcium carbonate. + Carbon dioxide is formed automatically when performing the ion donor treatment. Alternatively or additionally, carbon dioxide can be provided from an external source.

[0079] H3O + The ion donor treatment and the carbon dioxide treatment can be carried out simultaneously, when a strong or moderately strong acid is used. +The ion donor treatment can also be carried out first, for example, with a moderately strong acid having a pKa of 0-2.5 at 20° C., where carbon dioxide is formed in situ, and thus the carbon dioxide treatment can be carried out without the addition of HO. + It is carried out automatically simultaneously with the ion donor treatment, followed by an additional treatment with carbon dioxide supplied from an external source.

[0080] In a preferred embodiment, HO + The ion donor treatment step and / or the carbon dioxide treatment step are repeated at least once, more preferably several times. + The ion donor is added over a period of at least about 5 minutes, preferably at least about 10 minutes, typically from about 10 to about 20 minutes, more preferably about 30 minutes, even more preferably about 45 minutes, and sometimes over a period of about 1 hour or more.

[0081] H3O + Following the ion donor treatment and the carbon dioxide treatment, the pH of the aqueous suspension, measured at 20°C, spontaneously reaches a value of greater than 6.0, preferably greater than 6.5, more preferably greater than 7.0, even more preferably greater than 7.5, thereby preparing the surface-reacted natural or precipitated calcium carbonate as an aqueous suspension having a pH of greater than 6.0, preferably greater than 6.5, more preferably greater than 7.0, even more preferably greater than 7.5.

[0082] In a particularly preferred embodiment, the surface-reacted calcium carbonate is the reaction product of natural ground calcium carbonate (GNCC) with carbon dioxide and phosphoric acid, where the carbon dioxide is formed in situ by the phosphoric acid treatment.

[0083] Further details regarding the preparation of surface-reacted natural calcium carbonate are disclosed in WO 00 / 39222 A1, WO 2004 / 083316 A1, WO 2005 / 121257 A2, WO 2009 / 074492 A1, EP 2,264,108 A1, EP 2,264,109 A1 and US 2004 / 0020410 A1, the contents of which are incorporated herein by reference.

[0084] Similarly, surface-reacted precipitated calcium carbonate can be obtained. As is well known from WO 2009 / 074492 A1, surface-reacted precipitated calcium carbonate is prepared by reacting precipitated calcium carbonate with HO in an aqueous medium. + The present invention is obtained by contacting a surface-reacted precipitated calcium carbonate with an ion and an anion capable of being solubilized in an aqueous medium and forming a water-insoluble calcium salt in the aqueous medium to form a slurry of surface-reacted precipitated calcium carbonate, wherein said surface-reacted precipitated calcium carbonate comprises an insoluble, at least partially crystalline calcium salt of said anion formed on at least a surface of the precipitated calcium carbonate.

[0085] The solubilized calcium ions above are H3O + corresponds to the excess of solubilized calcium ions over those naturally produced upon dissolution of precipitated calcium carbonate by HO + The ions are provided only in the form of counterions to the anions, i.e., through addition of the anions in the form of an acid or non-calcium salt, and in the absence of any further calcium ions or calcium ion sources.

[0086] Said excess solubilized calcium ions is preferably provided by the addition of a soluble neutral or acidic calcium salt, or by the addition of an acid or a neutral or acidic non-calcium salt which generates a soluble neutral or acidic calcium salt in situ.

[0087] The above H3O + The ions may be provided by the addition of an acid or acid salt of the anions described above, or by the addition of an acid or acid salt which simultaneously serves to provide all or a portion of the extra solubilized calcium ions described above.

[0088] In a further preferred embodiment of the preparation of the surface-reacted natural or precipitated calcium carbonate, the natural or precipitated calcium carbonate is reacted with one or more HO in the presence of at least one compound selected from the group consisting of silicates, silicates, aluminum hydroxide, alkaline earth metal aluminates, such as sodium aluminate or potassium aluminate, magnesium oxide, or mixtures thereof. + The at least one silicate is preferably selected from aluminum silicate, calcium silicate, or alkaline earth metal silicate. These components react with one or more HO + Prior to the addition of the ion donor and / or carbon dioxide, it may be added to an aqueous suspension containing natural or precipitated calcium carbonate.

[0089] Alternatively, natural or precipitated calcium carbonate and one or more H2O + The silicate and / or silica and / or aluminium hydroxide and / or alkaline earth aluminate and / or magnesium oxide components can be added to the aqueous suspension of natural or precipitated calcium carbonate when the reaction with the ion donor and carbon dioxide has already started. Further details regarding the preparation of surface-reacted natural or precipitated calcium carbonate in the presence of at least one silicate and / or silica and / or aluminium hydroxide and / or alkaline earth aluminate component are disclosed in WO2004 / 083316A1, the content of which is incorporated herein by reference.

[0090] The surface-reacted calcium carbonate can be kept in suspension and, optionally, further stabilized by a dispersing agent. Conventional dispersing agents known to those skilled in the art can be used. A preferred dispersing agent is comprised of polyacrylic acid and / or carboxymethyl cellulose.

[0091] Alternatively, the above aqueous suspension can be dried, thereby obtaining surface-reacted natural or precipitated calcium carbonate solids (i.e., dry or containing small amounts of water that are not in fluid form) in the form of granules or powder.

[0092] In a particularly preferred embodiment of the present invention, the surface-reacted calcium carbonate is a mixture of natural ground calcium carbonate, carbon dioxide and one or more HO + The reaction product with the ion donor, where carbon dioxide is H3O + Formed in situ by ion donor treatment and containing one or more H + The ion donor is phosphoric acid. In the above embodiment, it is preferred that the surface-reacted calcium carbonate contains phosphate groups and has an atomic ratio of calcium to phosphorus atoms of at most 3.0, more preferably at most 2.5, and most preferably at most 2.3, as measured by XPS.

[0093] It is understood that the surface-reacted calcium carbonate is not a calcined material.

[0094] In a preferred embodiment, the surface-reacted calcium carbonate has a surface roughness of 15 m as measured using nitrogen and BET methods. 2 / g~200m 2 / g, preferably 27m 2 / g~180m 2 / g, more preferably 30m 2 / g~180m 2 / g, and even more preferably 45m 2 / g~180m 2 / g, most preferably 120m 2 For example, surface-reacted calcium carbonate has a specific surface area of ​​150 m / g to 180 m / g when measured using nitrogen and BET methods. 2 / g~180m 2 / g. The BET specific surface area in the sense of the present invention is defined as the surface area of ​​a particle divided by the mass of the particle. As used herein, the specific surface area is measured by adsorption using the BET isotherm (ISO 9277:2010) and is expressed as m 2 / g.

[0095] The surface-reacted calcium carbonate particles have a volume median particle size d of 1.0 to 75 μm, preferably 2 to 50 μm, more preferably 3 to 40 μm, even more preferably 4 to 30 μm, and most preferably 5 to 15 μm. 50 It is even more preferable that the volume is 1000 .mu.m.

[0096] The surface-reacted calcium carbonate particles have a top cut diameter of 2-150 μm, preferably 4-100 μm, more preferably 6-80 μm, even more preferably 8-60 μm, and most preferably 10-30 μm. 98 It is even more preferable that the volume is 1000 .mu.m.

[0097] d x The value is x% of this d x This represents a diameter that is less than d 98 A value of d means that 98% of all particles have a particle size smaller than that value. 98 The value is also called the "top cut". x The value can be given in volume or mass percent. Thus, d 50 The (wt) value is the weight median particle size, i.e. the size below which 50% by weight of all particles are smaller, and d 50 The (volume) value is the volume median particle size, ie the particle size below which 50% by volume of all particles are smaller.

[0098] Volume median particle size d 50 was evaluated using a Malvern Mastersizer 3000 laser diffraction instrument. 50 Or d 98 The values ​​indicate the diameter value such that 50% or 98% by volume of the particles have a diameter less than this value, respectively. The raw data obtained by the measurements are analyzed using Mie theory with a particle refractive index of 1.57 and an absorptivity of 0.005.

[0099] The weight median particle size of natural ground calcium carbonate and precipitated calcium carbonate is determined by the sedimentation method, which is an analysis of the sedimentation behavior in a gravitational field. The measurements are carried out on a Sedigraph™ 5120 (Micromeritics Instrument). This method and equipment is known to those skilled in the art and is commonly used to determine the particle size of fillers and pigments. The measurements are carried out in an aqueous solution of 0.1% by weight Na4P2O7. The samples are dispersed using a high speed stirrer and sonicated.

[0100] Methods and instruments are known to those skilled in the art and are commonly used to determine particle size of fillers and pigments.

[0101] The specific pore volume is measured using mercury intrusion porosimetry measurements using a Micromeritics Autopore V 9620 mercury porosimeter with a maximum applied pressure of 414 MPa (60,000 psi) mercury pressure, which corresponds to a Laplace throat diameter of 0.004 μm (~nm). The equilibration time used for each pressure step is 20 seconds. The sample material is cut into 5 cm 3 The powder is sealed in a chamber penetrometer. Data is constructed for mercury compression, penetrometer expansion, and sample material compression using the software Pore-Comp (Gane, PAC, Kettle, JP, Matthews, G. Pand Ridgway, CJ, "Void Space Structure of Compressible Polymer Spheres and Consolidated Calcium Carbonate Paper-Coating Formulations", Industrial and Engineering Chemistry Research, 35(5), 1996, p1753-1764).

[0102] The total pore volume seen in the cumulative indentation data can be separated into two regions with indentation data from 214 μm down to about 1-4 μm, indicating a strong contribution from the coarse grain packing of the sample between any aggregate structures. Below these diameters there is fine interparticle packing of the particles themselves. If they also have intraparticle porosity, this region appears bimodal and the specific intraparticle pore volume is defined by taking the specific pore volume indented by mercury to be the pores finer than the mode inflection point, i.e., the bimodal inflection point. The sum of these three regions gives the total pore volume of the powder, but is strongly dependent on the compaction of the original sample / settling of the powder at the coarse grain pore end of the distribution.

[0103] Taking the first derivative of the cumulative intrusion curve reveals the pore size distribution based on the equivalent Laplace diameter, which necessarily includes pore shielding. The derivative curve clearly shows the coarse aggregate pore structure region, the interparticle pore region, and the intraparticle pore region, if present. With knowledge of the intraparticle pore diameter range, it is possible to subtract the remaining interparticle and interagglomerate pore volumes from the total pore volume to yield the desired pore volume of only the internal pores in terms of pore volume per unit mass (specific pore volume) alone. Of course, the same principle of subtraction applies to isolate any of the other pore size regions of interest.

[0104] Preferably, the surface-reacted calcium carbonate has a thickness of 0.1 to 2.3 cm as calculated from mercury porosimetry measurements. 3 / g, more preferably 0.2 to 2.0 cm 3 / g, and particularly preferably 0.4 to 1.8 cm 3 / g, most preferably 0.6 to 1.6 cm 3 / g.

[0105] The intragranular pore size of the surface-reacted calcium carbonate, as measured by mercury porosimetry, is preferably in the range of 0.004 to 1.6 μm, more preferably 0.005 to 1.3 μm, particularly preferably 0.006 to 1.15 μm, and most preferably 0.007 to 1.0 μm.

[0106] According to a preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has a surface roughness of 10 to 200 m, as measured by the BET method. 2 / g, preferably 60 to 200m 2 / g, more preferably 100 to 200m 2 / g, and even more preferably 120 to 180 m 2 / g, most preferably 140 to 180m 2 Specific surface area (BET) in g / g and / or calculated from mercury porosimetry measurements of 0.10 to 2.0 cm 3 / g, more preferably 0.20 to 2.0 cm 3 / g, and even more preferably 0.50 to 2.0 cm 3 / g, most preferably 0.70 to 1.6 cm 3 / g range of intraparticle indented specific pore volume.

[0107] According to a preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has a surface roughness of 10 to 200 m, as measured by the BET method. 2 / g, preferably 60 to 200m 2 / g, more preferably 100 to 200m 2 / g, and even more preferably 120 to 180 m 2 / g, most preferably 140 to 180m 2 The specific surface area (BET) of 0.10 to 2.0 cm / g, calculated from mercury porosimetry measurements, is 3 / g, more preferably 0.20 to 2.0 cm 3 / g, and even more preferably 0.50 to 2.0 cm 3 / g, most preferably 0.70 to 1.6 cm 3 / g range of intraparticle indented specific pore volume.

[0108] According to one preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has a volume median particle size (d) of 0.5 to 50 μm, preferably 1 to 30 μm, more preferably 1.5 to 20 μm, most preferably 5 to 10 μm. 50), and / or a top cut (d 98 ) value.

[0109] According to one preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has a volume median particle size (d) of 0.5 to 50 μm, preferably 1 to 30 μm, more preferably 1.5 to 20 μm, most preferably 5 to 10 μm. 50 ), and a top cut (d 98 ) value.

[0110] According to one preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has and / or has a total number of basic sites of 0.01 to 0.6 mmol / g, preferably 0.05 to 0.5 mmol / g, more preferably 0.10 to 0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed carbon dioxide desorption; and / or It has a total acid site number of 0.01-0.6 mmol / g, preferably 0.05-0.5 mmol / g, and more preferably 0.10-0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed ammonia desorption.

[0111] According to one preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has having a total number of basic sites of 0.01 to 0.6 mmol / g, preferably 0.05 to 0.5 mmol / g, more preferably 0.10 to 0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed carbon dioxide desorption; and It has a total acid site number of 0.01-0.6 mmol / g, preferably 0.05-0.5 mmol / g, and more preferably 0.10-0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed ammonia desorption.

[0112] According to one preferred embodiment, the surface-reacted calcium carbonate provided in step (c) has a ratio of the total number of basic sites, determined by temperature programmed carbon dioxide desorption, to the total number of acid sites, determined by temperature programmed ammonia desorption, in the range of 45:55 to 75:25, preferably in the range of 55:45 to 70:30.

[0113] According to one embodiment, the surface-reacted calcium carbonate provided in step (b) comprises calcium carbonate and hydroxyapatite. According to one preferred embodiment, the surface-reacted calcium carbonate provided in step (b) has a ratio of the amount of hydroxyapatite to the amount of calcium carbonate in the range of 10:90 to 90:10, preferably 35:65 to 90:10, more preferably 60:40 to 90:10 (e.g. 70:30 to 85:15), as measured by XRD using the Riedveld technique.

[0114] 《Process (c)》 In step (c) of the process according to the invention, the alcohol provided in step (a) is evaporated.

[0115] After vaporization, the vaporized alcohol is carried in the vapor phase as part of the gaseous feed stream to the surface-reacted calcium carbonate as a catalyst for the Guerbet self-condensation reaction (see step (d)).

[0116] Suitable heating or vaporization devices, mass flow controllers, check valves, temperature controllers, supply lines for alcohol and carrier gas, alcohol reservoirs, gas cylinders, pumps, distribution lines, reactors, etc. can be selected according to the technical requirements and scale of the process by one skilled in the art.

[0117] The alcohol provided in step (a) can be fed in liquid form by means of a pump through a feed line to a vaporization reactor where the alcohol is vaporized according to step (c). A carrier gas feed line can be connected to the vaporization reactor, and the vaporized alcohol can be mixed with the carrier gas to generate a gaseous feed stream. The gaseous feed stream containing the vaporized alcohol can then be fed to a catalyst for reaction.

[0118] According to one embodiment, vaporized alcohol is mixed with a carrier gas to produce a gaseous feed stream.

[0119] A suitable carrier gas may be helium, nitrogen, argon, hydrogen, or a mixture thereof. The quality, source and / or purity of the carrier gas may be selected by one skilled in the art. In one particular embodiment, nitrogen is used as the carrier gas.

[0120] According to one embodiment of the present invention, the vaporized alcohol obtained in step (c) is mixed with an inert carrier gas. According to one embodiment of the present invention, the vaporized alcohol obtained in step (c) is mixed with a carrier gas selected from the group consisting of helium, nitrogen, argon, hydrogen and mixtures thereof, preferably the carrier gas is nitrogen.

[0121] The amount of vaporized alcohol can be adjusted by volume percentage of the gaseous feed stream. According to one embodiment, the vaporized alcohol obtained in step (c) is present in the gaseous feed stream in an amount of at least 2% by volume, preferably at least 5% by volume, more preferably 10-80% by volume, even more preferably 10-55% by volume, and most preferably 10-40% by volume.

[0122] The present inventors have found that the conversion and yield of the reaction can be further improved by adjusting the amount of evaporated alcohol relative to the volume of the gas feed stream to the range of 10-40% by volume.

[0123] For example, the vaporized alcohol obtained in step (c) is present in the gas feed stream in an amount of 15-35% by volume. In one particular embodiment, the vaporized alcohol obtained in step (c) is present in the gas feed stream in an amount of 15-20% by volume, or 25-35% by volume.

[0124] The gaseous feed stream containing vaporized alcohol may be purified, dried or otherwise treated as known in the art before being fed to step (d) of the process according to the invention.

[0125] 《Process (d)》 In step (d) of the process according to the invention, the vaporized alcohol obtained in step (c) is reacted in the presence of the surface-reacted calcium carbonate provided in step (b) as catalyst.

[0126] The reaction of the evaporated alcohol in step (d) is carried out in the gas phase. Therefore, the reaction in step (d) can be defined as a gas-phase Guerbet self-condensation reaction. As will be understood by those skilled in the art, the surface-reacted calcium carbonate used as a catalyst in step (d) should not be understood to be in a gaseous state either. The surface-reacted calcium carbonate used as a catalyst in step (d) is in a solid state, and therefore can also be defined as a heterogeneous catalyst.

[0127] The reaction, i.e. the Guerbet self-condensation of the vaporized alcohol obtained in step (c), can be carried out in any reactor suitable for gas-phase reactions. Non-limiting examples are plug flow reactors and packed bed or fixed bed reactors. The technical equipment for carrying out step (d), such as but not limited to preheaters, furnaces, coolers, cooling tanks, back pressure regulators, heat tracing, flow meters, filters, etc., can be selected by the skilled person as required.

[0128] The process of the present invention can be carried out as a batch process or a continuous process. It is preferred that the process is carried out as a continuous process. Thus, in one preferred embodiment, the alcohol is provided continuously in step (a), vaporized continuously in step (c), and reacted continuously in the presence of a catalyst (SRCC) in step (d).

[0129] The surface-reacted calcium carbonate provided in step (b) may be dried prior to reaction with the vaporized alcohol. Drying may be carried out by passing a stream of carrier gas over the surface-reacted calcium carbonate, preferably at elevated temperature (e.g. in the range of 100-500°C or 300-475°C).

[0130] According to one embodiment, the surface-reacted calcium carbonate is dried at a temperature in the range of 100-500°C, preferably 200-475°C, more preferably 300-475°C, before step (d). According to another embodiment, the surface-reacted calcium carbonate used in step (d) has a total residual moisture content of 0.01% to 0.75% by weight, preferably 0.02% to 0.5% by weight, based on the total dry weight of the surface-reacted calcium carbonate. According to a preferred embodiment, the surface-reacted calcium carbonate is dried at a temperature in the range of 100-500°C, preferably 200-475°C, more preferably 300-475°C, before step (d) and the surface-reacted calcium carbonate used in step (d) has a total residual moisture content of 0.01% to 0.75% by weight, preferably 0.02% to 0.5% by weight, based on the total dry weight of the surface-reacted calcium carbonate.

[0131] The reaction in step (d) is preferably carried out at a predetermined reaction temperature. According to one embodiment, step (d) is carried out at a reaction temperature in the range of 150 to 500°C, preferably 150 to 475°C, more preferably 250 to 475°C, even more preferably 350 to 475°C, and most preferably 375 to 475°C.

[0132] The inventors have found that a reaction temperature in the range of 375-475° C. is particularly advantageous for the process of the present invention.

[0133] The process can be defined by its weight hourly space velocity (WHSV). As used herein, "weight hourly space velocity" is defined as the weight of feed, i.e., the weight of the alcohol feed before evaporation in step (c), flowing per unit weight of catalyst (SRCC) per hour.

[0134] According to one embodiment, the weight hourly space velocity is at least 2 h -1 (For example, 2 to 2000 hours -1 ), preferably for at least 5 h. -1 (For example, 5 to 2000 hours -1 In one specific embodiment, the weight hourly space velocity is 2 to 200 h -1 , for example 5~100h -1 , or 10~100h -1 It is.

[0135] The reaction in step (d) produces an alcohol (also referred to herein as the "desired product") by condensing two molecules of alcohol provided in step (a). The alcohol obtained in step (d) contains the sum of the carbon atoms of the two molecules of primary or secondary alcohol provided in step (a), respectively. For example, if 2-propanol (a C3 alcohol) is provided as the secondary alcohol in step (a), the alcohol obtained in step (d) is 2-methyl-pentan-2-ol (a C6 alcohol). If ethanol (a C2 alcohol) is provided as the primary alcohol in step (a), the alcohol obtained in step (d) is n-butanol (a C4 alcohol), and so on.

[0136] The alcohol obtained in step (d) may be a straight chain alcohol or a branched chain alcohol. When the alcohol provided in step (a) has more than 3 carbon atoms, the alcohol obtained in step (d) is preferably a branched chain alcohol.

[0137] Preferably, the alcohol obtained in step (d) has a boiling point below 400°C, more preferably below 300°C, even more preferably below 250°C, and most preferably below 200°C.

[0138] The alcohol obtained in step (d) may be present in a product mixture with other products of the reaction. For example, the product mixture may contain aldehydes, ethers, esters, or other alcohols (e.g., alcohols having a higher molecular weight than the desired product), which are also referred to herein as "by-products." As will be appreciated by those skilled in the art, the by-products may be derived, for example, from intermediates (e.g., aldehydes) of the Guerbet reaction. Each of the by-products may have value in itself and may be individually separated and purified, if necessary.

[0139] According to one embodiment, the alcohol is obtained in step (d) as part of a product mixture that includes one or more by-products, such as, but not limited to, alkenes, aldehydes, ethers, esters, or other alcohols.

[0140] The reaction in step (d) can have a particular selectivity for the desired product. As used herein, "selectivity" refers to the selectivity (S) calculated by the following formula: S j :n j / (n i 0 -n i ) x 100 where n i 0 is the initial amount of alcohol in moles C (moles of carbon) before step (d), and n i is the amount of C moles of unreacted alcohol after step (d), and n j is the amount of C moles of product j in the reaction product stream.

[0141] In one embodiment, the alcohol (desired product) is obtained in step (d) with a selectivity of at least 15% (e.g., 15 to 99.99%), preferably at least 30% (e.g., 30 to 99.99%), more preferably at least 40% (e.g., 40 to 99.99%), and most preferably at least 50% (e.g., 50 to 99.99%).

[0142] The vaporized alcohol obtained in step (c) can be reacted in step (d) in a certain amount, which can be expressed as the conversion percentage or conversion rate of the starting material (the vaporized alcohol provided in step (c)). As used herein, the "conversion rate" is the conversion rate (X) calculated by the following formula: X i :n i 0 -n i / n i 0 ×100 where n i 0 is the initial amount of C moles of alcohol before step (d), and n i is the amount of C moles of unreacted alcohol after step (d).

[0143] According to one embodiment, the reaction in step (d) has a conversion of at least 5% (e.g., 5 to 99.99%), preferably at least 10% (e.g., 10 to 99.99%), more preferably at least 15% (e.g., 15 to 99.99%), and most preferably at least 20% (e.g., 20 to 99.99%).

[0144] Without being limited thereto, the process of the present invention may include one or more additional steps, such as condensation of the reaction product, purification of the reaction product, feeding the reaction product into a second reaction, recycling of by-products, recycling of the surface-reacted calcium carbonate, reusing the recycled surface-reacted calcium carbonate as a catalyst, etc. The additional steps may be combined in any order according to the needs of the skilled artisan.

[0145] According to one embodiment, the method comprises a step (e) of condensing the reaction product obtained in step (d) and / or a step (f) of purifying the reaction product obtained in step (d) or (e).

[0146] Use according to the present invention In another aspect, the present invention relates to the use of surface-reacted calcium carbonate as a catalyst for the Guerbet self-condensation reaction in the gas phase, wherein the surface-reacted calcium carbonate is a mixture of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) with carbon dioxide and one or more HO. + Carbon dioxide is a reaction product with ion donors, and H3O + The calcium carbonate formed in situ by ion donor treatment and / or provided from an external source and surface-reacted has a surface roughness of at least 15 m when measured using nitrogen and the BET method according to ISO 9277:2010. 2 / g.

[0147] It is to be understood that the embodiments and preferred embodiments of the surface-reacted calcium carbonate provided in step (b) of the inventive process disclosed above and herein are also embodiments and preferred embodiments of the surface-reacted calcium carbonate for use in the present invention. To further illustrate this, certain embodiments and preferred embodiments of the surface-reacted calcium carbonate for use in the present invention are repeated below.

[0148] According to one embodiment, the surface-reacted calcium carbonate for use according to the invention has a volume median particle size (d) of 1.0 to 75 μm, preferably 2 to 50 μm, more preferably 3 to 40 μm, even more preferably 4 to 30 μm, and most preferably 5 to 15 μm. 50 ), and / or a top cut (d 98 ) value.

[0149] According to one embodiment, the surface-reacted calcium carbonate for use according to the invention has a viscosity of 15 to 200 m, as measured by the BET method. 2 / g, preferably 27 to 180 m 2 / g, more preferably 30 to 180m 2 / g, and even more preferably 45 to 180 m 2 / g, most preferably 120 to 180m 2 / g specific surface area (BET).

[0150] According to one embodiment, the surface-reacted calcium carbonate for use according to the invention has a thickness of 0.10 to 2.3 cm 3 / g, more preferably 0.20 to 2.0 cm 3 / g, and even more preferably 0.40 to 1.8 cm 3 / g, most preferably 0.70 to 1.6 cm 3 / g.

[0151] According to one embodiment, one or more HO + The ion donor is selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, citric acid, oxalic acid, acid salts, acetic acid, formic acid, and mixtures thereof, preferably hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, H2PO4 - and the corresponding cation, e.g. Li + , Na + Or K + , HPO4 2- and at least partially neutralized by the corresponding cation, e.g. Li + , Na + , K + , Mg 2+ , or Ca 2+ and mixtures thereof, more preferably selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, or mixtures thereof, and most preferably one or more of HO. + The ion donor is phosphoric acid.

[0152] According to one embodiment, the surface-reacted calcium carbonate for use according to the invention is a mixture of ground natural calcium carbonate (GNCC) and carbon dioxide and one or more HO + reaction product with an ion donor, where one or more HO + The ion donor is phosphoric acid, and carbon dioxide is HO + It is formed in situ by ion donor treatment.

[0153] According to one embodiment, the surface-reacted calcium carbonate for use according to the present invention has a total number of base sites of 0.01-0.6 mmol / g, preferably 0.05-0.5 mmol / g, more preferably 0.10-0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed carbon dioxide desorption and / or a total number of acid sites of 0.01-0.6 mmol / g, preferably 0.05-0.5 mmol / g, more preferably 0.10-0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature programmed ammonia desorption.

[0154] According to one preferred embodiment of the present invention, the surface-reacted calcium carbonate is used as a catalyst for the Guerbet self-condensation reaction in the gas phase of primary or secondary alcohols having at least one β-hydrogen.

[0155] Further and preferred embodiments of the primary or secondary alcohol are disclosed above in connection with the process according to the invention. Certain selected and preferred embodiments are repeated below.

[0156] According to one embodiment, the surface-reacted calcium carbonate is used as a catalyst for the Guerbet self-condensation reaction of primary or secondary alcohols having a boiling point below 200° C., preferably below 175° C., more preferably below 145° C., most preferably below 125° C.

[0157] According to one embodiment, the surface-reacted calcium carbonate is used as a catalyst for the Guerbet self-condensation reaction of primary alcohols.

[0158] According to one embodiment, the surface-reacted calcium carbonate is a branched or linear C2-C 12 It is used as a catalyst for the Guerbet self-condensation reaction of primary or secondary alcohols having alkyl chains, preferably branched or linear C2-C6 alkyl chains.

[0159] According to one embodiment, the surface-reacted calcium carbonate is used as a catalyst for the Guerbet self-condensation reaction of alcohols selected from the group consisting of ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-propanol, 2-methyl-1-propanol, 2-butanol, 3-methyl-2-butanol, 2-butanol, and 3-pentanol. EXAMPLES

[0160] 《1.Measurement method》 The measurement methods used in the examples are described below.

[0161] 《Particle size distribution》 Volumetric median particle size d 50 (Volume) and volumetric top cut particle size d 98 (volume) was assessed using a Malvern Mastersizer 3000 laser diffraction instrument (Malvern Instruments Plc, UK). 50 (volume) or d 98 The (volume) values ​​indicate the diameter value such that 50% or 98% by volume of the particles, respectively, have a diameter below this value. The raw data obtained by the measurements were analyzed using Mie theory with a particle refractive index of 1.57 and an absorptivity of 0.005. The methods and instruments are known to those skilled in the art and are commonly used to determine the particle size distribution of fillers and pigments. The samples were measured in the dry state without pretreatment.

[0162] Gravimetric median particle size d50 The particle size distribution (weight) was measured by the sedimentation method, which is an analysis of the sedimentation behavior in a gravitational field. The measurements were performed using a Sedigraph™ 5120 from Micromeritics Instrument, USA. This method and equipment is known to those skilled in the art and is commonly used to determine the particle size distribution of fillers and pigments. The measurements were performed in a 0.1 wt% Na4P2O7 aqueous solution. The samples were dispersed using a high speed stirrer and sonicated.

[0163] 《Specific surface area (SSA)》 The specific surface area was measured by the BET method according to ISO 9277:2010 with nitrogen, after which the samples were conditioned by heating for 30 min at 250° C. Prior to such measurements, the samples were filtered in a Büchner funnel, rinsed with deionized water and dried in an oven at 110° C. for at least 12 h.

[0164] Intraparticle specific pore volume (cm 3 / g)》 The specific pore volume was measured using mercury intrusion porosimetry measurements using a Micromeritics Autopore V 9620 mercury porosimeter with a maximum applied pressure of 414 MPa (60,000 psi) mercury pressure, which corresponds to a Laplace throat diameter of 0.004 μm (~nm). The equilibration time used at each pressure step was 20 seconds. Sample material was removed from 5 cm 3The powder was sealed in a chamber powder penetrometer. Data were corrected for mercury compression, penetrometer expansion, and sample material compression using the software Pore-Comp (Gane, PAC, Kettle, JP, Matthews, G. Pand Ridgway, CJ, "Void Space Structure of Compressible Polymer Spheres and Consolidated Calcium Carbonate Paper-Coating Formulations", Industrial and Engineering Chemistry Research, 35(5), 1996, p1753-1764).

[0165] The total pore volume seen in the cumulative indentation data can be separated into two regions with indentation data from 214 μm down to about 1-4 μm, indicating a strong contribution from the coarse grain packing of the sample between any aggregate structures. Below these diameters there is fine interparticle packing of the particles themselves. If they also have intraparticle porosity, this region appears bimodal and a specific intraparticle pore volume is defined by taking the specific pore volume into which mercury indents the finer pores than the mode turning point, i.e., the bimodal point of the inflection. The sum of these three regions gives the total pore volume of the powder, but is strongly dependent on the compaction of the original sample / settling of the powder at the coarse grain pore end of the distribution.

[0166] Taking the first derivative of the cumulative intrusion curve reveals the pore size distribution based on the equivalent Laplace diameter, which necessarily includes pore shielding. The derivative curve clearly shows the coarse aggregate pore structure region, the interparticle pore region, and the intraparticle pore region, if present. With knowledge of the intraparticle pore diameter range, it is possible to subtract the remaining interparticle and interagglomerate pore volumes from the total pore volume to derive the desired pore volume of the single internal pore in terms of pore volume per unit mass (specific pore volume). Of course, the same principle of subtraction applies to isolate any of the other pore size regions of interest.

[0167] Scanning Electron Microscope (SEM) Samples were prepared by diluting 50-150 μl of the slurry sample with 5 ml of water. The amount of the slurry sample depends on the solid content, the average particle size, and the particle size distribution. The diluted samples were filtered using a 0.8 μm membrane filter. A finer filter was used when the filtrate was cloudy. A conductive double-sided adhesive tape was attached onto an SEM stub. This SEM stub was then pressed slightly into the still wet filter cake on the filter. The SEM stub was then sputtered with 8 nm of Au. The prepared samples were subsequently examined by: a Sigma VP field emission scanning electron microscope (FESEM) (Carl Zeiss AG, Germany) and a variable pressure secondary electron detector (VPSE) and / or a secondary electron detector (SE) with a chamber pressure of about 50 Pa. Investigations under the FESEM (Zeiss Sigma VP) were carried out at 5 kV (Au).

[0168] 《X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA)》 XRD patterns were recorded on a Bruker D2 Phaser powder X-ray diffractometer using a Co radiation source, CoKα=1.789Å. Measurements were performed between 10 and 70° 2θ using a scan rate of 0.5 s per step. TGA was performed using a Mettler Toledo TGA / DSC3+. Samples were heated from 25°C to 600°C with a 25°C gradient and held at 105°C and 500°C for 10 min with an air flow of 80 ml / min. XPS experiments were performed on a Kratos AXIS Ultra DLD analyzer using monochromatic Al Kα radiation (hu=1486.6 eV) operating at 225 W (15 mA, 15 kV). The base pressure of the instrument was 5×10-10 Torr.

[0169] Further experimental techniques The Ca and P content of the SRCC solids was investigated by dissolving a sample of SRCC in aqua regia (a mixture of 1 part nitric acid (70 wt % in water) and 3 parts hydrochloric acid (35 wt % in water) by volume, diluting the resulting solution with water until the volume increased approximately 4-fold, and analyzing the diluted solution via inductively coupled plasma optical emission spectroscopy (ICP-OES) technique using a Perkin Elmer Avio 500 instrument. The Ca and P contents were determined using calibration curves.

[0170] Adsorbed ammonia and adsorbed carbon dioxide temperature programmed desorption (NH3-TPD and CO2-TPD) The measurements were carried out using a Micromeritics ASAP2920 instrument. 0.1 g of sample was dried in situ under a flow of He with a temperature gradient of 5° C. / min up to 400° C. For NH3-TPD measurements, the sample was cooled to 100 °C. At this point, a 5 cm 3 20 pulses of 10 vol.% NH in He were dispensed onto the sample (25.3 cm 3 The desorption of NH3 was then induced by heating the sample to 600 °C with a gradient of 5 °C / min. A thermal conductivity detector was used to measure the desorbed NH3 over this time. For quantitative evaluation, the TCD concentration was plotted over time and temperature to determine the temperature position of the desorption peak. In both cases, peak decomposition was performed. Baseline subtraction and full integration of the desorption profile were performed to obtain the total amount of desorbed NH3. Peak decomposition was performed using the software Fityk.

[0171] After obtaining the area under the curve (AUC, A) (Fittic), the AUC is converted to a quantifiable amount of NH3 (nNH3 in mmol / g) using the following formula: A r =A / 100% V NH3,abs =A r ×V V NH3 =V NH3,abs / m sample m NH3 =V NH3 ×ρNH3 n NH3 =m NH3 / M NH3 ρ NH3 =0.76kg / m 3 , M NH3 = 17 g / mol A = area obtained (% x min), A r = area (min), V = flow rate 25.2 (cm 3 / min) V NH3,abs = absolute amount of desorbed NH3 (cm 3 ) V NH3 = amount of desorbed NH3 per 1 g of sample (cm 3 / g)

[0172] For CO2-TPD measurements, the samples were cooled to 50 °C and a procedure similar to that described for NH3-TPD was used. ρCO2 = 1.98 kg / m 3 and MCO2 = 44.01 g / mol, and the number of basic sites was determined according to the above calculation. To calculate the number of acidic or basic sites, it was assumed that only one molecule of NH3 or CO2 could be adsorbed on a single site.

[0173] 《2.Materials》 Surface-reacted calcium carbonate (SRCC) 《SRCC1》 SRCC1 is d 50 (Volume) = 6.6 μm, d 98 (Volume) = 13.7 μm, and intraparticle intrusion specific pore volume 0.939 cm 3 / g (pore diameter: 0.004 to 0.51 μm).

[0174] SRCC1 was obtained by preparing 350 liters of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of ground limestone calcium carbonate from Omya SAS, Orgon to obtain a solids content of 10% by weight based on the total weight of the aqueous suspension, where the ground limestone calcium carbonate had a weight-based median particle size d of 1.3 μm as measured by sedimentation. 50(wt).

[0175] 11.2 kg of phosphoric acid in the form of an aqueous solution containing 30% by weight of phosphoric acid was added to the above suspension at a temperature of 70° C. over a period of 20 minutes while mixing the slurry at a speed of 6.2 m / s.

[0176] After the addition of the acid, the slurry was stirred for an additional 5 minutes after which it was removed from the vessel and dried using a jet dryer.

[0177] 《SRCC2》 SRCC2 is d 50 (Volume) = 5.8 μm, d 98 (Volume) = 15.4 μm, and intraparticle intrusion specific pore volume 1.070 cm 3 / g (pore diameter 0.004 to 0.34 μm).

[0178] SRCC2 was obtained by preparing 10 liters of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of ground marble calcium carbonate from Hustadmarmor Norway to obtain a solids content of 10% by weight based on the total weight of the aqueous suspension. The ground calcium carbonate had a 90% weight based particle size distribution of less than 2 μm as measured by sedimentation. Additionally, a phosphoric acid solution was prepared to contain 30% phosphoric acid based on the total weight of the solution.

[0179] While mixing the slurry, 1.8 kg of phosphoric acid solution was added over 10 minutes. After 20% of the total acid solution had been added, 53 g of anhydrous citric acid powder was added to the slurry. The temperature of the suspension was maintained at 70°C + / - 1°C throughout the experiment. Finally, after the addition of the acid, the suspension was stirred for an additional 5 minutes before it was removed from the vessel and allowed to cool.

[0180] 《SRCC3》 SRCC3 is d 50 (Volume) = 8.3 μm, d 98 (Volume) = 18.7 μm, and intraparticle intrusion specific pore volume 1.565 cm 3 / g (pore diameter 0.004 to 0.66 μm).

[0181] SRCC3 was obtained by preparing 10 liters of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of ground marble calcium carbonate from Karabiga, Turkey to obtain a solids content of 15% by weight based on the total weight of the aqueous suspension. The ground calcium carbonate had a median particle size (d) of 1.4 μm by weight as measured by sedimentation. 50 (by weight). A phosphoric acid solution was also prepared containing 30% phosphoric acid based on the total weight of the solution.

[0182] While mixing the slurry, 2.8 kg of phosphoric acid solution was added over 15 minutes. The temperature of the suspension was maintained at 70° C.+ / -1° C. throughout the experiment. Finally, after the addition of the acid, the suspension was stirred for an additional 5 minutes after which it was removed from the vessel and allowed to cool.

[0183] Other Reagents All commercial reagents were used as received without further purification. Ethanol (technical grade (99.5%) was obtained from VWR chemicals. HAP-H (hydroxyapatite; 5 μm particle size) was purchased from Sigma-Aldrich. MgO (98%) was obtained from Acros organics.

[0184] The properties of the surface-reacted calcium carbonate are shown in Tables 1 to 3. The properties of the commercially available catalysts are also shown in Table 1.

[0185] [Table 1]

[0186] [Table 2]

[0187] [Table 3]

[0188] 3. Example Guerbet reaction

[0189] The Guerbet reaction of ethanol was carried out in a continuous U-shaped fixed-bed flow-through borosilicate reactor (inner diameter 8 mm). The liquid feed was stirred for 4–22 h. -1 The mixture was delivered by an HPLC pump (LC-20AT, Shimadzu) at a weight hourly space velocity (WHSV) of 1000 sq. m. The flow of N2 carrier gas was controlled using a mass flow controller (F-201CV, Bronkhorst). Prior to the reaction, the catalyst bed was dried with flowing N2 (100 mL / min) at 400 °C for 2 h. All catalytic experiments were carried out at atmospheric pressure and temperatures between 350 and 450 °C. In a typical experiment, the reactor was loaded with catalyst (0.05–0.3 g) sandwiched between quartz wool plugs. Ethanol was evaporated in N2 and the resulting stream containing 10–64 vol.% ethanol (23.6 mmol / h) was fed to the reactor at 12.5–200 mL / min. The reaction products were analyzed by an on-line GC (Brucker, 430-GC) equipped with an FID detector and a PoraPLOT Q-HT analytical column. The catalytic activity of the catalyst was characterized by the conversion (X), the selectivity to the products (S), and the yield (Y): X i :n i 0 -n i / n i 0 ×100 S j :n j / (n i 0 -n i ) x 100 Y j :X i ×S j / 100 where n i 0 is the initial amount of C moles of ethanol, and n i is the unreacted moles of ethanol, n j is C moles of product J in the reaction product stream.

[0190] The catalytic performance was evaluated in flow at 400° C. for 3 hours. Table 4 summarizes the test results. Entry 1 shows negligible conversion under non-catalytic conditions with only traces of acetaldehyde formation. Entries 2 and 3 are the performances shown by commercial solid base catalysts such as MgO and hydroxyapatite (HAP-H), respectively. HAP-H showed better conversion and 1-butanol selectivity compared to MgO. Entries 4-6 relate to examples of the present invention using SRCC1-SRCC3 as catalysts. As can be seen from the results, the conversion of the substrate as well as the selectivity and yield for 1-butanol in entries 4-6 are improved compared to the commercial catalyst MgO. Moreover, the results of entries 4 to 6 are similar or better than the commercial catalyst HAP-H.

[0191] Among all the SRCC catalysts (entries 4-6), SRCC2 showed the best performance with the highest 1-butanol yield. Compared to commercial HAP-H, SRCC2 showed better conversion with good butanol yield. Besides the main products 1-butanol and acetaldehyde, the by-products seen throughout all the reactions included various C4 products such as diethyl ether, 1-butanal, ethyl acetate, crotonaldehyde, and C6 products such as 1-hexanol.

[0192] [Table 4]

[0193] Reaction conditions: Catalyst amount = 0.1g; WHSV (weight hourly space velocity) = 11h -1 Ethanol feed rate = 23.6 mmol / h; Ethanol volume = 18%; N2 flow rate = 100 mL / min; Temperature = 400 °C; Flow time = 3 h; HAP-H = hydroxyapatite (surface area - 100 m 2 / g); catalyst drying = 2 hours at 400 °C under N2 flow; X = conversion; S = selectivity; Y = yield.

[0194] Using the best catalyst, SRCC2, the reaction parameters were optimized and the results are shown in Table 5. Results are given for an initial time on stream of 3 h and a final time of 18 h. Entries 1-4 show the study of catalyst loading as reflected by WHSV; ethanol conversion decreased upon decreasing catalyst loading (and increasing WHSV). Entries 3 and 5-8 show the change in vol% ethanol in the stream, while entries 6, 9 and 10 show the dependence of reaction temperature. Overall, the best performance of ethanol conversion with good butanol selectivity was achieved with a catalyst loading of 0.1 g (WHSV = 11 h). -1 ), was obtained at 30% by volume of ethanol in the air stream and a reaction temperature of 400°C.

[0195] [Table 5]

[0196] Reaction conditions: Ethanol feed rate=23.6 mmol / h; catalyst drying=2 h at 400° C. under flowing N2; X=conversion; S=selectivity of 1-butanol; Y=yield of 1-butanol.

[0197] A detailed comparison of the performance of SRCC2 with the commercial HAP-H catalyst is shown in Table 6. The comparison was performed to ascertain the catalyst stability versus catalytic performance over extended reaction times. Over the course of the reaction, the SRCC2 catalyst performed better than the commercial HAP-H.

[0198] [Table 6]

[0199] Reaction conditions: catalyst amount = 0.1 g; WHSV (weight hourly space velocity) = 11 h -1 Ethanol feed rate = 23.6 mmol / h; Ethanol volume = 30%; N2 flow rate = 50 mL / min; Temperature = 400 °C; HAP-H = hydroxyapatite (surface area - 100 m 2 / g); catalyst drying = 400 °C for 2 h under N2 flow; X = conversion; Y = butanol yield.

Claims

1. A method for producing an alcohol by a gas-phase gelbe self-condensation reaction, comprising the following steps: (a) providing a primary or secondary alcohol having at least one β-hydrogen; (b) providing surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) with carbon dioxide and one or more H ３ O ＋ ion donors, wherein the carbon dioxide is formed in situ by treatment with the H ３ O ＋ ion donors and / or supplied from an external source, and the surface-reacted calcium carbonate has a specific surface area of at least 15 m ２ / g as measured using the BET method in accordance with nitrogen and ISO 9277:2010; (c) vaporizing the alcohol provided in step (a); (d) reacting the vaporized alcohol obtained in step (c) in the presence of the surface-reacted calcium carbonate as the catalyst provided in step (b).

2. The process according to claim 1, wherein the primary or secondary alcohol provided in step (a) has a boiling point of less than 200 °C, preferably less than 175 °C, more preferably less than 145 °C, and most preferably less than 125 °C.

3. The method according to claim 1, wherein the alcohol provided in step (a) is a primary alcohol.

4. The primary or secondary alcohol provided in step (a) is a branched-chain or straight-chain C ２ -C １２ alkyl chain, preferably a primary or secondary alcohol having a branched-chain or straight-chain C ２ -C ６ alkyl chain, or The primary or secondary alcohol provided in step (a) is selected from the group consisting of ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-propanol, 2-methyl-1-propanol, 2-butanol, 3-methyl-2-butanol, 2-butanol, and 3-pentanol, The method according to claim 1.

5. The surface-reacted calcium carbonate provided in step (b) has a volume median particle size (d ５０ ), and / or a top cut (d ９８ ) value of 2 to 150 μm, preferably 4 to 100 μm, more preferably 6 to 80 μm, even more preferably 8 to 60 μm, and most preferably 10 to 30 μm, and the method according to claim 1.

6. The surface-reacted calcium carbonate provided in step (b) has a specific surface area (BET) of 15 to 200 m ２ / g, preferably 27 to 180 m ２ / g, more preferably 30 to 180 m ２ / g, even more preferably 45 to 180 m ２ / g, most preferably 120 to 180 m ２ / g, according to the method of claim 1.

7. The surface-reacted calcium carbonate provided in step (b) has an intruded mercury ratio pore volume of 0.10 to 2.3 cm ３ / g, more preferably 0.20 to 2.0 cm ３ / g, even more preferably 0.40 to 1.8 cm ３ / g, most preferably 0.70 to 1.6 cm ３ / g, and the method according to claim 1.

8. The one or more H ３ O ＋ ion donors are selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, citric acid, oxalic acid, acid salts, acetic acid, formic acid, and mixtures thereof, Preferably selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, the corresponding cations, e.g., H2PO4− at least partially neutralized by Li+, Na+ or K+, HPO42− at least partially neutralized by the corresponding cations, e.g., Li+, Na+, K+, Mg2+ or Ca2+, and mixtures thereof, More preferably selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, or mixtures thereof, Most preferably, one or more H ３ O ＋ The ion donor is phosphoric acid, The method according to claim 1.

9. The surface-reacted calcium carbonate is a reaction product of ground natural calcium carbonate (GNCC), carbon dioxide, and one or more H ３ O ＋ ion donors, and the one or more H ３ O ＋ ion donors are phosphoric acid, and the carbon dioxide is formed in situ by treatment with the H ３ O ＋ ion donors, the method according to claim 1.

10. The surface-reacted calcium carbonate provided in step (b) has a total base site number of 0.01 to 0.6 mmol / g, preferably 0.05 to 0.5 mmol / g, more preferably 0.10 to 0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature-programmed carbon dioxide desorption, and / or has a total acid site number of 0.01 to 0.6 mmol / g, preferably 0.05 to 0.5 mmol / g, more preferably 0.10 to 0.45 mmol / g, based on the total dry weight of the surface-reacted calcium carbonate, as measured by temperature-programmed ammonia desorption. The method according to claim 1.

11. The surface-reacted calcium carbonate is dried at a temperature in the range of 100 to 500°C, preferably 300 to 475°C, before step (d), and / or the surface-reacted calcium carbonate used in step (d) has a residual total moisture content of 0.01 wt% to 0.75 wt%, preferably 0.02 wt% to 0.5 wt%, based on the total dry weight of the surface-reacted calcium carbonate. The method according to claim 1.

12. The vaporized alcohol obtained in step (c) is present in the gas feed stream in an amount of at least 2% by volume, preferably 10 to 80% by volume, more preferably 10 to 55% by volume, most preferably 10 to 40% by volume, and / or the vaporized alcohol obtained in step (c) is mixed with a carrier gas selected from the group consisting of helium, nitrogen, argon, hydrogen, and mixtures thereof, preferably nitrogen. The method according to claim 1.

13. Step (d) is carried out at a reaction temperature in the range of 150 to 500°C, preferably 150 to 475°C, more preferably 250 to 475°C, most preferably 375 to 475°C. The method according to claim 1.

14. Use of surface-reacted calcium carbonate as a catalyst for the gelbe self-condensation reaction in the gas phase, wherein the surface-reacted calcium carbonate is a reaction product of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) with carbon dioxide and one or more H ３ O ＋ ion donors, and wherein the carbon dioxide is formed in situ and / or supplied from an external source by treatment with the H ３ O ＋ ion donors, and wherein the surface-reacted calcium carbonate has a specific surface area of at least 15 m ２ / g as measured using nitrogen and the BET method according to ISO 9277:2010.

15. The use according to claim 14, wherein the gelbe self-condensation reaction is a reaction of a primary or secondary alcohol according to any one of claims 1 to 4.