Static mixers in production of alicyclic carboxylic acids and their esters

Abstract

To provide a process for producing alicyclic compounds, preferably alicyclic carboxylic acids and esters thereof, using a static mixer, and apparatuses for carrying out this process.SOLUTION: A process for preparing one or more alicyclic compounds includes: (i) providing a stream A of one or more aromatic compounds and a stream B of a hydrogen-containing hydrogenation gas; (ii) bringing the streams A and B prepared in (i) into contact by at least one to at most 8 static mixers 4, thereby obtaining a mixed stream C5 and introducing the mixed stream C5 into a hydrogenation unit 6; (iii) hydrogenating the one or more aromatic compounds in the hydrogenation unit 6 to obtain one or more corresponding alicyclic compounds; and (iv) obtaining a product mixture containing the one or more alicyclic compounds.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention belongs to the field of production of alicyclic compounds by ring hydrogenation of aromatic compounds. The present invention provides a process for producing alicyclic compounds, preferably alicyclic carboxylic acids and their esters, using a static mixer, and an apparatus for carrying out this process.

Background Art

[0002] Alicyclic polycarboxylic acid esters, such as esters of cyclohexane-1,2-dicarboxylic acid, are used as lubricant components and as auxiliaries in metalworking. They are also used as plasticizers for polyolefins and PVC. For the plasticization of PVC, esters of phthalic acid, such as dinonyl ester or didecyl ester, are mainly used. However, the use of phthalates is increasingly becoming the subject of debate among the public, and their use in plastics may be restricted. Although some alicyclic polycarboxylic acid esters have already been reported in the literature as plasticizers for plastics, they may be a suitable alternative as a possible substitute for restricted plasticizers. The most economical process for the production of alicyclic polycarboxylic acid esters is generally the ring hydrogenation of the corresponding aromatic polycarboxylic acid esters, such as the above phthalates. Many processes for this process are already known.

[0003] Patent Document 1 discloses the hydrogenation of dimethyl terephthalate on a supported ruthenium catalyst at 110°C to 140°C and 35 to 105 bar.

[0004] In Patent Document 2, an aromatic carboxylic acid ester is hydrogenated on a supported Ni, Ru, Rh and / or Pd catalyst at 70°C to 250°C and 30 to 200 bar to obtain the corresponding alicyclic carboxylic acid ester.

[0005] Patent Documents 3 and 4 disclose a process for hydrogenating benzene polycarboxylic acid esters to obtain the corresponding alicyclic compounds.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0007] The hydrogenation of aromatic compounds is carried out, for example, by reacting an aromatic compound-containing starting material in a liquid phase with a hydrogen-containing hydrogenation gas. For this purpose, the hydrogenation gas must be dissolved in the liquid phase. When introducing the hydrogenation gas and the liquid starting material into the hydrogenation unit, the concentration of hydrogen transferred from the gas phase to the liquid phase increases over the entire length of the hydrogenation unit. As a result, different reaction rates occur within the hydrogenation unit, and accordingly, different space-time yields occur within the hydrogenation unit. That is, overall, this concentration gradient causes a decrease in the yield of the entire hydrogenation process. Therefore, the main problem of the present invention was to provide a process for producing alicyclic compounds, preferably alicyclic carboxylic acids and their esters, in which the space-time yield is substantially constant over the entire length of the hydrogenation apparatus.

Means for Solving the Problems

[0008] This main problem of the present invention is a process for preparing one or more alicyclic compounds, comprising the following: (i) providing a stream A of one or more aromatic compounds and a stream B of a hydrogen-containing hydrogenation gas; (ii) contacting at least one and up to eight static mixers (4) with the flows A and B prepared in (i) above to obtain a mixed flow C (5), and introducing the mixed flow C (5) into a hydrogenation unit (6); (iii) in the hydrogenation unit (6), hydrogenating the one or more aromatic compounds to obtain one or more corresponding alicyclic compounds; and (iv) obtaining a product mixture comprising the one or more alicyclic compounds; has been achieved by providing a process comprising the steps of:

[0009] A static mixer is a mixing element capable of mixing two or more input streams with each other by virtue of its internal shape. A static mixer includes a pipe with flow elements and / or internal structures. Mixing is effected by guiding the input streams across the flow elements within the pipe and can thus create turbulent flow. A static mixer can mix a substance system composed of two or more components in the gas phase, liquid phase, supercritical phase or particle phase. In this case, at least one static mixer is used. Up to eight static mixers connected in parallel or in series can also be used. Using the smallest possible number of static mixers is already advantageous in terms of cost. The static mixer includes a pipe into which the two flows A and B are supplied via a common inlet. The pipe has at least one, preferably two or more, flow elements disposed therein. The flow elements effect the desired mixing of the two flows A and B to form the flow C.

[0010] In the context of the present invention, it has been found that by incorporating a static mixer into the hydrogenation apparatus, the starting materials are mixed prior to entering the hydrogenation apparatus, whereby the hydrogen concentration in the liquid phase increases significantly immediately at the start. This improves the reaction in the initial region of the hydrogenation unit.

[0011] The term "alicyclic compound" in the context of the present invention should be understood to mean a compound having an aliphatic structure and a saturated ring system. Such a compound is also known as an alicyclic compound. Preferably, the alicyclic compound obtained as a product in the context of the present invention has a cyclohexane ring.

[0012] The term "aromatic compound" in the context of the present invention should be understood to mean a compound having at least one ring system containing 4n + 2 delocalized electrons according to Hückel's rule, conjugated double bonds, lone pairs of electrons or unoccupied p orbitals. Preferably, the aromatic compound used as a starting material in the context of the present invention has a benzene ring.

[0013] "Hydrogen-containing hydrogenation gas" is a gas containing hydrogen. In the context of the reaction underlying the present invention, in addition to the aromatic compound, hydrogen is used as another starting material. In the hydrogenation reaction carried out, the double bonds of the ring of the aromatic compound used, preferably the benzene ring, are hydrogenated by an addition reaction of hydrogen and thereby broken. The reaction is carried out in the presence of a solid catalyst. The hydrogen molecules in the hydrogen-containing hydrogenation gas are intermediate-bonded to the metal atoms of the catalyst, the bond between the two hydrogen atoms in the hydrogen molecule is weakened, and it can interact with an electron-rich multiple bond (double bond). Hydrogenation occurs when two hydrogen atoms formally migrate to each double bond. Thereby, the double bond of the aromatic compound is cleaved and an alicyclic compound is obtained. The hydrogenation gas used may be any hydrogen-containing gas mixture that does not contain a catalyst poison such as carbon monoxide or hydrogen sulfide in a harmful amount. Preferably, an inert gas may be used in some cases, and hydrogen with a purity of more than 95%, particularly more than 98% is used. The inert gas component may be, for example, nitrogen or methane. Preferably, the amount of hydrogen present in the hydrogenation unit is in excess, particularly in excess by 1% to 200%, preferably in excess by 3% to 100%, particularly preferably in excess by 5% to 50%, relative to the stoichiometric amount required for this hydrogen to achieve the desired conversion rate or the conversion rate possible in the hydrogenation unit. By setting hydrogen sufficiently in excess, it can have an advantageous effect on the complete hydrogenation of the aromatic bond.

[0014] The term "hydrogenation unit" in the context of the present invention should be understood to mean a hydrogenation reactor, or a series of two or more reactors connected in series, or a parallel connection of two or more reactors, or a group of reactors consisting of parallel and series-connected reactors. Therefore, it should be understood to mean a reactor or reactor arrangement that can perform the function of a reactor in the process according to the present invention.

[0015] Individual hydrogenation units can be filled with fresh hydrogen. However, in order to minimize hydrogen consumption and effluent losses resulting from off-gas, it is convenient to use the off-gas of one hydrogenation unit as hydrogenation gas for other or the same hydrogenation unit. Furthermore, the exhaust gas of the hydrogenation unit can be reused as fresh hydrogen after post-treatment. For example, in a process carried out in two series-connected hydrogenation units each having a reactor, it is advantageous to supply fresh hydrogen into the first hydrogenation unit and to introduce the exhaust gas of the first hydrogenation unit into the second hydrogenation unit. In this case, the starting material and the hydrogenation gas can flow through the hydrogenation units in the reverse order or can be premixed using, for example, a static mixer. In carrying out this process, it is advantageous to maintain the hydrogen excess below 30%, in particular below 20%, relative to the stoichiometrically required amount. The hydrogenation according to the present invention is preferably carried out in a liquid / gas mixed phase or a liquid phase in two hydrogenation units connected in series. The first hydrogenation unit is operated in a loop mode, i.e., a part of the hydrogenation effluent from the first hydrogenation unit is led to the top of the first hydrogenation unit together with fresh starting materials. Preferably, the resupply is carried out by introduction into a static mixer or by supply without using a static mixer. The other part of the output from the first hydrogenation unit is hydrogenated in the second hydrogenation unit in a straight-through mode. Preferably, a static mixer may be present in the supply conduit to the second hydrogenation unit. Instead of one large hydrogenation unit in loop mode, two or more smaller hydrogenation units arranged in series or in parallel may be used in loop mode. Instead of one large hydrogenation unit with a linear through-flow, two or more hydrogenation units connected in series or in parallel may also be operated. Preferably, the static mixer is present in each supply conduit to the individual hydrogenation units. Preferably, a hydrogenation unit operated in loop mode and a hydrogenation unit operated in straight-through mode are used.

[0016] The hydrogenation can be carried out in the absence of a solvent or preferably in the presence of a solvent. The solvent used may be any liquid that forms a homogeneous solution with the starting materials and the product, is inert under the hydrogenation conditions, and can be easily separated from the product. The solvent may also be a mixture of two or more substances and may optionally contain water. Preferably, when a solvent is present, the solvent is also mixed with the starting materials provided in (i) above by means of a static mixer. For example, the following substances: linear or cyclic ethers such as tetrahydrofuran or dioxane, and aliphatic alcohols having an alkyl group with 1 to 13 carbon atoms, may be used as the solvent. Alcohols that can preferably be used as solvents include isopropanol, n-butanol, isobutanol, n-pentanol, 2-ethylhexanol, nonanol, industrial nonanol mixture, decanol, industrial decanol mixture, and tridecanol.

[0017] When using an alcohol as a solvent, it is convenient to use the alcohol or alcohol mixture formed by hydrolysis of the product. This will prevent the formation of by-products by transesterification. A more preferred solvent is the hydrogenated product itself. When using a solvent, the concentration of aromatic compounds in the feed to the hydrogenation unit can be restricted, and as a result, temperature control in the hydrogenation unit can be achieved better. Thereby, side reactions are minimized, and thus the product yield can be increased. Preferably, the content of aromatic compounds in the feed to the hydrogenation unit is 1% to 35% by mass, preferably 2% to 25% by mass, based on the total amount of the starting materials. The desired concentration range in the case of a hydrogenation unit operated in a loop mode can be adjusted by the circulation ratio (the ratio of the amount of recycled hydrogenation effluent to the starting material).

Brief Description of the Drawings

[0018]

Figure 1

Embodiments for Carrying Out the Invention

[0019] The process according to the present invention will be described below as an example using the example of the system shown in FIG. 1. The starting materials are supplied to a static mixer via at least two pipelines (1, 2), which are combined, optionally, to form a single stream (3). Preferably, one of the two pipelines contains a hydrogen-containing hydrogenation gas and the other contains an aromatic compound in liquid form. These are then introduced into a static mixer (4) and supplied as a homogeneous mixture via a pipeline (5) to a hydrogenation unit (6), where a hydrogenation reaction takes place. The product stream (7) contains a mixture of the alicyclic compound as the product and residues of the residual concentrations of the starting materials. Preferably, the product stream (7) at the outlet of the hydrogenation unit contains less than 0.3% by mass, preferably less than 0.1% by mass, particularly less than 0.05% by mass, and particularly preferably less than 0.005% by mass of the aromatic compound used as the starting material.

[0020] The shape of the static mixer is a shape that provides a flow greater than 100, preferably greater than 200, particularly greater than 500, and particularly preferably greater than 900 within the static mixer. A person skilled in the art can determine the Reynolds number based on the shape of the static mixer. The general formula for the Reynolds number is known to a person skilled in the art. More preferably, the shape of the static mixer is such that it results in the mixing of the hydrogenation gas provided in (i) above with the aromatic compound provided in the liquid phase, and the hydrogen from the hydrogen-containing hydrogenation gas is present in the liquid phase at a substantially saturated concentration at the end of the static mixer. A person skilled in the art can determine the saturated concentration in the liquid phase. "At a substantially saturated concentration" in the context of the present invention means that the concentration of hydrogen in the liquid phase is at most 15%, preferably at most 10%, particularly preferably at most 5%, and even more preferably at most 1% below the saturated concentration. This means, for example, that if the saturated concentration of hydrogen in the liquid phase is 1 g / L, a concentration of 0.85 g / L of hydrogen in the liquid phase also means that the saturated concentration is present.

[0021] Therefore, the static mixer is more preferably designed to be selected from the group consisting of the following mixer types: Kenics mixer, Sulzer SMV mixer, Sulzer SMX mixer, Fluitec CSE mixer, and Ross ISG mixer. The Kenics mixer has a shape that carries the input flow through a helical mixing element, radially in the direction of the pipe wall, and then back towards the center. A combination of elements twisted alternately to the left and right causes additional reversal of the flow direction and splitting of the flow. These flow profiles mix the input flow.

[0022] In the context of the present invention, the hydrogenation of the aromatic compound prepared in (i) is preferably carried out using the hydrogen-containing gas prepared in (i) on one or more solid catalysts arranged in the fixed bed of the hydrogenation unit.

[0023] More preferably, the solid catalyst contains at least one metal of a Group 8 transition element of the periodic table of elements. Preferably, as the active metal, platinum, rhodium, palladium, cobalt, nickel, ruthenium, or a mixture of two or more thereof is used, and in particular, ruthenium is used as the active metal. More preferably, the above metal and at least one metal of a Group 1 and / or Group 7 transition element of the periodic table of elements are present in the catalyst. Preferably, a metal of a Group 8 transition element of the periodic table of elements and rhenium and / or copper are used.

[0024] The catalyst used in the context of this process is the above metal applied on a carrier material. The carrier material used is preferably a material containing micropores (pore diameter less than 2 nm), mesopores (pore diameter of 2 - 50 nm), and macropores (pore diameter greater than 50 nm). For example, regarding the types of pores, the following: a) only mesopores b) micropores and mesopores c) mesopores and macropores d) micropores, mesopores, and macropores e) micropores and macropores A carrier material with combined pores may be used. As the carrier material, preferably, activated carbon, silicon carbide, aluminum oxide, silicon oxide, aluminosilicate, titanium dioxide, zirconium dioxide, magnesium oxide and / or zinc oxide, or a mixture thereof is used. As the carrier material, a solid that is sufficiently inert under hydrogenation conditions is advantageously used. Examples include activated carbon, silicon carbide, silicon dioxide, titanium dioxide and / or zirconium dioxide, and mixtures of these compounds. Most particularly preferably, titanium dioxide is used as the carrier material. Titanium dioxide exists in three polymorphs (anatase, rutile and brookite), of which anatase and rutile are the most common. A preferred carrier material is Aerolyst 7711 (registered trademark) (Evonik Operations GmbH). This carrier material consists of rutile in the range of 15 - 20% by mass and anatase in the range of 80 - 85% by mass. Further examples of suitable titanium dioxide carrier materials are manufactured based on titanium dioxide from the sulfuric acid process. They generally contain >98% anatase. In the process according to the invention, the hydrogenation in (iii) is carried out in the liquid phase or in the gas phase. The hydrogenation may be carried out continuously or batchwise on a suspension catalyst or on a catalyst arranged in pieces in a fixed bed. In the process according to the invention, continuous hydrogenation on a catalyst in the form of a fixed bed is advantageous, where the product / starting material phase is mainly in the liquid state under the reaction conditions. The hydrogenation in (iii) is preferably carried out at a pressure of 3 - 300 bar, preferably 15 - 200 bar, particularly preferably 50 - 150 bar. The hydrogenation in (iii) is preferably carried out at a temperature of 50°C - 250°C, preferably 70°C - 200°C. Due to the exothermic nature of the hydrogenation reaction, the reaction does not occur at a fixed temperature, but rather within the temperature range described herein. Thus, the temperature of the reaction mixture rises as it passes through the hydrogenation unit.

[0025] In the context of the process according to the invention, in (i) above, one or more aromatic carboxylic acid esters are provided, preferably one or more aromatic mono-, di- and polycarboxylic acid esters. In the context of the process of the invention, aromatic compounds such as aromatic polycarboxylic acids and / or aromatic monocarboxylic acids or derivatives thereof, in particular their alkyl esters, may be converted into the corresponding alicyclic polycarboxylic acid compounds. Both the complete esters and the partial esters can be hydrogenated. A complete ester is understood to be a compound in which all acid groups are esterified. A partial ester is a compound having at least one free acid group (or optionally an anhydride group) and at least one ester group. When using polycarboxylic acid esters in the process according to the invention, advantageously they contain 2, 3 or 4 ester functional groups. In the context of the process according to the invention, in (i) above, one or more benzene-, diphenyl-, naphthalene-, diphenyl oxide-, anthracenedi- or -polycarboxylic acid esters are provided. The alicyclic polycarboxylic acid or its derivative obtained by the process according to the invention consists of one or more C6 rings and, where appropriate, is linked or fused by carbon-carbon bonds.

[0026] In (i) above, a branched or unbranched alkoxyalkyl group, cycloalkyl and / or alkyl group having 1 to 25 carbon atoms, preferably C8 - C 10 phthalate, C8 - C 10 terephthalate, C8 - C 10 isophthalate and C8 - C 10 trimellitate, and particularly preferably one or more aromatic carboxylic acid esters having an alcohol component selected from the group consisting of di-2-ethylhexyl phthalate, diisononyl phthalate, di-2-ethylhexyl terephthalate, diisononyl terephthalate, di-2-ethylhexyl isophthalate, diisononyl isophthalate, tri-2-ethylhexyl trimellitate and triisononyl trimellitate are provided. Here, C8 preferably means 2-ethylhexyl or n-octyl, C9 means isononyl, and C 10 means isodecyl or 2-propylheptyl.

[0027] This process is preferably a process for hydrogenating benzene-1,2-, -1,3- or -1,4-dicarboxylic acid esters, and / or benzene-1,2,3-, -1,2,4- or -1,3,5-tricarboxylic acid esters, whereby isomers of cyclohexane-1,2-, -1,3- or -1,4-dicarboxylic acid esters, or isomers of cyclohexane-1,2,3-, -1,3,5- or -1,2,4-tricarboxylic acid esters are obtained.

[0028] In the process according to the invention, for example, the following aromatic carboxylic acid esters can be used: naphthalene-1,2-dicarboxylic acid, naphthalene-1,3-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-1,6-dicarboxylic acid, naphthalene-1,7-dicarboxylic acid, naphthalene-1,8-dicarboxylic acid, phthalic acid (benzene-1,2-dicarboxylic acid), isophthalic acid (benzene-1,3-dicarboxylic acid), terephthalic acid (benzene-1,4-dicarboxylic acid), benzene-1,2,3-tricarboxylic acid, benzene-1,2,4-tricarboxylic acid (trimellitic acid), benzene-1,3,5-tricarboxylic acid (trimesic acid), benzene-1,2,3,4-tetracarboxylic acid. Also, one or more hydrogen atoms bonded to the aromatic ring may be substituted with an alkyl, cycloalkyl or alkoxyalkyl group using an acid formed from the above acids. For example, preferably, alkyl, cycloalkyl and alkoxyalkyl esters of the above acids are used, where the groups independently contain 1 to 25 carbon atoms, particularly 3 to 15 carbon atoms, very particularly 8 to 13 carbon atoms, especially 9 carbon atoms. The groups may be straight-chain or branched. When there are more than one ester group in the starting material, the groups may be the same or different.

[0029] Examples of esters of aromatic polycarboxylic acids that can be used in the process according to the present invention include the following compounds: monomethyl terephthalate, dimethyl terephthalate, diethyl terephthalate, di-n-propyl terephthalate, dibutyl terephthalate, diisobutyl terephthalate, di-tert-butyl terephthalate, dipentyl terephthalate, monoglycol terephthalate, diglycol terephthalate, n-octyl terephthalate, diisooctyl terephthalate, di-2-ethylhexyl terephthalate, di-n-nonyl terephthalate, diisobutyl terephthalate, di-2-propylheptyl terephthalate, di-n-decyl terephthalate, di-n-undecyl terephthalate, diisodecyl terephthalate, ditridecyl terephthalate, di-n-octadecyl terephthalate, diisooctadecyl terephthalate, di-n-eicosyl terephthalate, monocyclohexyl terephthalate; monomethyl phthalate, dimethyl phthalate, di-n-propyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-tert-butyl phthalate, monoglycol phthalate, diglycol phthalate, di-n-octyl phthalate, diisooctyl phthalate, di-2-ethylhexyl isophthalate, di-n-nonyl isophthalate, diisononyl isophthalate, di-n-decyl phthalate, di-2-propylheptyl phthalate, diisodecyl phthalate, di-n-undecyl phthalate, diisoundecyl phthalate, ditridecyl phthalate, di-n-octadecyl phthalate, diisooctadecyl phthalate, di-n-eicosyl terephthalate, monocyclohexyl phthalate;Examples include dicyclohexyl phthalate, monomethyl isophthalate, dimethyl isophthalate, diethyl isophthalate, di-n-propyl isophthalate, di-n-butyl isophthalate, diisobutyl isophthalate, di-tert-butyl isophthalate, monoglycol isophthalate, diglycol isophthalate, di-n-octyl isophthalate, diisooctyl isophthalate, di-2-ethylhexyl isophthalate, di-n-nonyl isophthalate, diisononyl isophthalate, di-n-decyl isophthalate, diisodecyl isophthalate, di-n-undecyl isophthalate, diisododecyl isophthalate, di-n-dodecyl isophthalate, ditridecyl isophthalate, di-n-octadecyl isophthalate, diisooctadecyl isophthalate, di-n-eicosyl isophthalate, and monocyclohexyl isophthalate.;

[0030] The process according to the invention can in principle also be applied to benzoic acid and its esters. This is understood to also mean alkyl benzoates and benzoates of diols, such as glycol dibenzoate, diethylene glycol benzoate, triethylene glycol dibenzoate or propylene glycol dibenzoate. The carbon atoms of the alcohol component of the alkyl benzoate may consist of 1 to 25, preferably 8 to 13, and each may be straight-chain or branched-chain.;

[0031] On an industrial scale, aromatic esters, especially fully esters, are often preferably produced from alcohol mixtures. Examples of suitable alcohol mixtures include the following: The C5 alcohol mixture is produced from linear butenes by hydrogenation after hydroformylation; the C5 alcohol mixture is produced from a butene mixture containing linear butenes and isobutene by hydrogenation after hydroformylation; the C6 alcohol mixture is produced from pentene or a mixture of two or more pentenes by hydrogenation after hydroformylation; the C7 alcohol mixture is produced from trimerization of ethylene or dimerization of propylene or hexene isomers or another mixture of hexene isomers by hydrogenation after hydroformylation; the C8 alcohol mixture, such as 2-ethylhexanol (two isomers), is produced by hydrogenation after aldol condensation of n-butyl aldehyde; the C9 alcohol mixture is produced from C4 olefins by dimerization, hydroformylation and hydrogenation. The production of C9 alcohol may be carried out from isobutene, or from a mixture of linear butenes, or from a mixture of linear butenes and isobutene. The C4 olefins can be dimerized using various catalysts such as protic acids, zeolites, organometallic nickel compounds or solid nickel-containing catalysts. The C8 olefin mixture may be hydroformylated using a rhodium catalyst or a cobalt catalyst; C 10 The alcohol mixture is produced by hydroformylation of tripropylene and subsequent hydrogenation; 2-propylheptanol (two isomers) is produced by aldol condensation of valeraldehyde and subsequent hydrogenation. C 10 The C alcohol mixture is prepared from a mixture of at least two C5 aldehydes by aldol condensation and subsequent hydrogenation; the C13 alcohol mixture is prepared from hexaethylene, tetrapropylene or tributene by hydroformylation and subsequent hydrogenation. Other alcohol mixtures can be obtained by hydroformylation and subsequent hydrogenation from olefins or olefin mixtures that occur, for example, in Fischer-Tropsch synthesis, dehydrogenation of hydrocarbons, metathesis reactions, polygas processes, or other industrial processes. To prepare the alcohol mixture, an olefin mixture with olefins of different carbon numbers can also be used.

[0032] In the process according to the invention, any ester mixture produced from aromatic polycarboxylic acids and the above alcohol mixture can be used. In the present invention, preferably, an ester produced from phthalic acid or phthalic anhydride and a mixture of isomeric alcohols having 4 to 13 carbon atoms is used.

[0033] Preferably, the process according to the invention comprises the following steps: (i) Preparing one or more aromatic compounds selected from the group consisting of esters of phthalic acid, isophthalic acid, terephthalic acid and trimellitic acid, particularly preferably one or more aromatic compounds selected from the group consisting of di-n-butyl terephthalate, dipentyl terephthalate, di-2-ethylhexyl terephthalate, diisononyl terephthalate, dipentyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, dipentyl isophthalate, di-2-ethylhexyl isophthalate, diisononyl isophthalate, tripentyl trimellitate, tri-2-ethylhexyl trimellitate, triisononyl trimellitate, or mixtures thereof, and a hydrogen-containing hydrogenation gas; (ii) Contacting the substances prepared in (i) above using a static mixer and introducing them into a hydrogenation unit (6); (iii) Hydrogenating the one or more aromatic compounds in the hydrogenation unit (6) to obtain one or more corresponding alicyclic compounds; (iv) To obtain a product mixture containing one or more alicyclic compounds selected from the group consisting of dialkyl cyclohexane-1,2-dicarboxylates, dialkyl cyclohexane-1,3-dicarboxylates, dialkyl cyclohexane-1,4-dicarboxylates and cyclohexane-1,2,4-tricarboxylate, particularly preferably, di-n-butyl cyclohexane-1,4-dicarboxylate, dipentyl cyclohexane-1,4-dicarboxylate, di-2-ethylhexyl cyclohexane-1,4-dicarboxylate, diisononyl cyclohexane-1,4-dicarboxylate, dipentyl cyclohexane-1,2-dicarboxylate, di-2-ethylhexyl cyclohexane-1,2-dicarboxylate, diisononyl cyclohexane-1,2-dicarboxylate, dipentyl cyclohexane-1,3-dicarboxylate, di-2-ethylhexyl cyclohexane-1,3-dicarboxylate, di-2-ethylhexyl cyclohexane-1,3-dicarboxylate, diisononyl cyclohexane-1,3-dicarboxylate, tripentyl cyclohexane-1,2,4-tricarboxylate, tri-2-ethylhexyl cyclohexane-1,2,4-tricarboxylate, triisononyl cyclohexane-1,2,4-tricarboxylate, to obtain a product mixture containing one or more alicyclic compounds selected from the group consisting of; is included. The product obtained depends on the starting materials used. For example, when diisononyl phthalate is used as the starting material, diisononyl cyclohexane-1,2-dicarboxylate is obtained as the product. Therefore, di-2-ethylhexyl cyclohexane-1,2-dicarboxylate is obtained from di-2-ethylhexyl phthalate.

[0034] Preferably, the process according to the present invention comprises the following steps: (i) Providing a starting material containing diisononyl phthalate (DINP) or di-2-ethylhexyl phthalate (DEHP) and a hydrogen-containing hydrogenation gas; (ii) contacting the substance prepared in (i) using a static mixer and introducing it into the hydrogenation unit (6); (iii) in the hydrogenation unit (6), hydrogenating the one or more aromatic compounds to obtain the corresponding alicyclic compounds; (iv) obtaining a product mixture comprising diisononyl cyclohexane-1,2-dicarboxylate or di-2-ethylhexyl cyclohexane-1,2-dicarboxylate; is included. Furthermore, for example, when diisononyl terephthalate is used as the starting material, diisononyl cyclohexane-1,4-dicarboxylate is obtained as the product. Thus, di-2-ethylhexyl cyclohexane-1,4-dicarboxylate is obtained from di-2-ethylhexyl terephthalate.

[0035] Preferably, the process according to the invention comprises the following steps: (i) providing a starting material comprising diisononyl terephthalate or di-2-ethylhexyl terephthalate and a hydrogen-containing hydrogenation gas; (ii) contacting the substance prepared in (i) using a static mixer and introducing it into the hydrogenation unit (6); (iii) in the hydrogenation unit (6), hydrogenating the one or more aromatic compounds to obtain the corresponding alicyclic compounds; (iv) obtaining a product mixture comprising diisononyl cyclohexane-1,4-dicarboxylate or di-2-ethylhexyl cyclohexane-1,4-dicarboxylate; is included. Furthermore, for example, when triisononyl trimellitate is used as the starting material, triisononyl cyclohexane-1,2,4-tricarboxylate is obtained as the product. Thus, tri-2-ethylhexyl cyclohexane-1,2,4-tricarboxylate is obtained from tri-2-ethylhexyl trimellitate.

[0036] Preferably, the process according to the invention comprises the following steps: (i) Providing a starting material containing triisooctyl trimellitate (TINTM) or tri-2-ethylhexyl trimellitate (TOTM) and a hydrogen-containing hydrogenation gas; (ii) Contacting the material prepared in (i) using a static mixer and introducing it into a hydrogenation unit (6); (iii) In the hydrogenation unit (6), hydrogenating the one or more aromatic compounds to obtain the corresponding alicyclic compounds; (iv) Obtaining a product mixture containing triisooctyl cyclohexane-1,2,4-tricarboxylate or tri-2-ethylhexyl cyclohexane-1,2,4-tricarboxylate; is included.

[0037] The process according to the present invention is preferably carried out under the following conditions. A Kenics mixer with a Reynolds number exceeding 100 in the mixer is installed in the feed to the hydrogenation unit. In the mixer feed, the concentration of the aromatic compound as the starting material is 5% to 30% by mass, particularly 8% to 15% by mass. In the effluent from the hydrogenation unit, the concentration of the starting material is 0.3% to 8% by mass, particularly 1.5% to 4% by mass. After introducing the effluent from the static mixer into the hydrogenation unit, a hydrogenation reaction is carried out on the catalyst. The specific liquid hourly space velocity (LHSV, liters of fresh starting material per hour per liter of catalyst) in the hydrogenation apparatus is 0.1 to 5 / hour (h -1 ), particularly 0.5 to 3 / hour. The surface load in the hydrogenation unit is in the range of 25 to 140 m 3 / m 2 / hour, particularly in the range of 50 to 90 m 3 / m 2 / hour. The average hydrogenation temperature in the hydrogenation unit is 70 to 150 °C, particularly 80 to 120 °C. The hydrogenation pressure in the hydrogenation unit is 25 to 200 bar, particularly 80 to 110 bar. The variant of this process is particularly suitable for the hydrogenation of phthalic esters, especially isononyl phthalate (''diisononyl phthalate'' as a mixture of isomers, for example VESTINOL® 9 from Evonik OXENO GmbH & Co. KG).

[0038] A further aspect of the invention comprises at least one hydrogenation unit (6), a static mixer (4) and one or more feed streams (1, 2), said static mixer being configured to bring the feed streams A and B (1, 2) into contact with each other and then introduce them via a stream C (5) into the hydrogenation unit (6). The apparatus according to the invention preferably comprises two, three, four or more feed streams to the static mixer. Preferably, the hydrogenation unit (6) contains one or more solid catalysts, preferably said solid catalysts containing at least one metal of transition elements of Group 8 of the Periodic Table of the Elements, particularly preferably ruthenium. The description in this specification applies mutatis mutandis to the catalysts used.

[0039] In the hydrogenation unit, preferably, a mixture of an aromatic compound and the corresponding alicyclic compound, preferably an aromatic carboxylic acid ester having an alcohol component selected from the group consisting of branched or unbranched alkoxyalkyl groups, cycloalkyl and / or alkyl groups having 1 to 25 carbon atoms and its corresponding alicyclic compound, more preferably C8-C 10 phthalate, C8-C 10 terephthalate, C8-C 10 isophthalate, C8-C 10Trimellitate, di-2-ethylhexyl phthalate, diisononyl phthalate, di-2-ethylhexyl terephthalate, diisononyl terephthalate, di-2-ethylhexyl isophthalate, diisononyl isophthalate, tri-2-ethylhexyl trimellitate and triisononyl trimellitate, diisononyl phthalate and / or didecyl phthalate and diisononyl cyclohexanedicarboxylate and / or didecyl cyclohexanedicarboxylate and their corresponding alicyclic compounds are present.

[0040] A further aspect of the present invention is the use of a static mixer for bringing two or more feed streams into contact before introducing them into one or more hydrogenation units, preferably for bringing an aromatic compound into contact with a hydrogen-containing hydrogenation gas, preferably wherein said mixer is of Kenics mixer design. Preferably, the shape of the static mixer is preferably such that it provides a flow having a Reynolds number greater than 100, preferably greater than 200, particularly greater than 500, and particularly preferably greater than 900, within the static mixer. Preferably, the shape of the static mixer is such that it results in the mixing of the hydrogenation gas provided in (i) above with the aromatic compound provided in the liquid phase, and such that hydrogen from the hydrogen-containing hydrogenation gas is present in the liquid phase at a substantially saturated concentration at the end of the static mixer.

[0041] In the context of the present invention, it is advantageous to use the alicyclic polycarboxylic acid ester produced according to the present invention as a plasticizer in plastics. Preferred plastics are PVC, ethylene, propylene, butadiene, vinyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylate, acrylate having an alkyl group bonded to the oxygen atom of the ester group, branched or unbranched alcohols having 1 to 10 carbon atoms, styrene, homo- and copolymers based on acrylonitrile, or homo- or copolymers of cyclic olefins. Representative examples of the above group include the following plastics: A polyacrylate, polymethacrylate, polymethyl methacrylate, methyl acrylate-butyl acrylate copolymer, methyl methacrylate-butyl methacrylate copolymer, ethylene-vinyl acetate copolymer, chlorinated polyethylene, nitrile rubber, acrylonitrile-butadiene-styrene copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene rubber, styrene-butadiene elastomer, methyl methacrylate-styrene-butadiene copolymer and / or nitrocellulose, having an alkyl group of the same or different carbon atoms of 4 to 8 bonded to the oxygen atom of the ester group, particularly n-butyl, n-hexyl, n-octyl and 2-ethylhexyl groups, and isononyl group, may be mentioned. The alicyclic polycarboxylic acid ester produced according to the present invention can further be used for modifying plastic mixtures, for example, a mixture of polyolefin and polyamide. The alicyclic polycarboxylic acid ester produced according to the present invention can be used for the above applications and as a lubricant component, a component of a coolant and a metalworking fluid. It can also be used as a component in paints, coatings, inks and adhesives.

Claims

1. 1. A process for preparing one or more alicyclic compounds comprising: (i) providing one or more aromatic compound streams A and a hydrogen-containing hydrogenation gas stream B; (ii) contacting the streams A and B provided in (i) with at least one and up to eight static mixers to obtain a mixed stream C, and introducing the mixed stream C into a hydrogenation unit; (iii) hydrogenating the one or more aromatic compounds in the hydrogenation unit to obtain one or more corresponding alicyclic compounds; and (iv) obtaining a product mixture comprising said one or more alicyclic compounds; The process includes:

2. 2. The process of claim 1, wherein the static mixer comprises a pipe into which two of said streams A and B are fed through a common inlet, and in which at least one, or two or more flow elements are disposed that provide the desired mixing of the two of said streams A and B.

3. 3. The process of claim 1 or 2, wherein the static mixer is a design selected from the group consisting of the following mixer types: Kenics mixer, Sulzer SMV mixer, Sulzer SMX mixer, Fluitec CSE mixer, and Ross ISG mixer.

4. The process according to any one of claims 1 to 3, wherein the hydrogenation in (iii) is carried out using a hydrogen-containing hydrogenation gas provided in (i) over a solid catalyst arranged in a fixed bed of the hydrogenation unit.

5. 5. The process of claim 4, wherein the solid catalyst comprises at least one metal of the transition group 8 of the periodic table of the elements or ruthenium.

6. The process of any one of claims 1 to 5, wherein the hydrogenation in (iii) is carried out at a pressure of from 3 to 300 bar, from 15 to 200 bar, or from 50 to 150 bar.

7. The process according to any one of claims 1 to 6, wherein the hydrogenation in (iii) is carried out at a temperature of from 50°C to 250°C, preferably from 70°C to 200°C.

8. The process according to any one of claims 1 to 7, wherein in (i) one or more aromatic carboxylic acid esters, one or more aromatic mono-, di- or poly-carboxylic acid esters are provided.

9. 9. The process of any one of claims 1 to 8, wherein in (i) one or more benzene-, diphenyl-, naphthalene-, diphenyloxide-, anthracenedi- or polycarboxylic acid esters are provided.

10. In the above (i), a branched or unbranched alkoxyalkyl group, a cycloalkyl and / or an alkyl group having 1 to 25 carbon atoms, C ８ ~C １０ Phthalate, C ８ ~C １０ Terephthalate, C ８ ~C １０ Isophthalate, C ８ ~C １０ 10. The process of any one of claims 1 to 9, wherein one or more aromatic carboxylic acid esters are provided having an alcohol component selected from the group consisting of di-2-ethylhexyl phthalate, diisononyl phthalate, di-2-ethylhexyl terephthalate, diisononyl terephthalate, di-2-ethylhexyl isophthalate, diisononyl isophthalate, tri-2-ethylhexyl trimellitate and triisononyl trimellitate.

11. 11. The process of any one of claims 1 to 10, wherein the static mixer is configured to provide a flow within the static mixer with a Reynolds number greater than 100, greater than 200, greater than 500, or greater than 900.

12. 12. An apparatus for carrying out the process of any one of claims 1 to 11, comprising at least one hydrogenation unit, a static mixer and one or more feed streams, said static mixer configured to contact said one or more feed streams with each other before introducing them via stream into said hydrogenation unit.

13. 13. The apparatus of claim 12, wherein the hydrogenation unit comprises one or more solid catalysts, preferably the one or more solid catalysts comprising at least one metal of the transition group 8 of the periodic table of the elements or ruthenium.

14. In the hydrogenation unit, a mixture of an aromatic compound and a corresponding alicyclic compound; a mixture of an aromatic carboxylic acid ester having an alcohol component selected from the group consisting of branched or unbranched alkoxyalkyl, cycloalkyl and / or alkyl groups having 1 to 25 carbon atoms and a corresponding alicyclic compound; C ８ ~C １０ Phthalate, C ８ ~C １０ Terephthalate, C ８ ~C １０ Isophthalate, C ８ ~C １０ 14. The device according to claim 12 or 13, wherein the alicyclic compounds of the formula (I) are present: di-2-ethylhexyl phthalate, diisononyl phthalate, di-2-ethylhexyl terephthalate, diisononyl terephthalate, di-2-ethylhexyl isophthalate, diisononyl isophthalate, tri-2-ethylhexyl trimellitate and triisononyl trimellitate, diisononyl phthalate and / or didecyl phthalate and diisononyl cyclohexane dicarboxylate and / or didecyl cyclohexane dicarboxylate and their corresponding alicyclic compounds.

15. 1. Use of a static mixer for contacting two or more feed streams prior to introduction into one or more hydrogenation units, or for contacting aromatic compounds with a hydrogen-containing hydrogenation gas, preferably said static mixer being of Kenics mixer design.

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