Temperature control in preparation of alicyclic polycarboxylic acids and esters thereof

Abstract

To provide techniques for preparation of alicyclic compounds through a ring hydrogenation of aromatic compounds.SOLUTION: The invention provides a process of preparing alicyclic compounds, preferably alicyclic carboxylic acids and esters thereof, and an apparatus for carrying out the process.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention belongs to the technical field of the production of alicyclic compounds by ring hydrogenation of aromatic compounds. The present invention provides a method for producing an alicyclic compound, preferably an alicyclic carboxylic acid and its ester, and an apparatus for carrying out the method.

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 metal processing. They are also used as plasticizers for polyolefins and PVC.

[0003] For the plasticization of PVC, esters of phthalic acid, such as dibutyl, dioctyl, dinonyl or didecyl esters, are mainly used. The use of these phthalates has become an increasingly controversial topic among the general public, and their use in plastics may be restricted. Some of the alicyclic polycarboxylic acid esters have already been described in the literature as plasticizers for plastics, but they may be a suitable choice as an alternative to the above-mentioned restricted plasticizers.

[0004] The most economical method for the production of alicyclic polycarboxylic acid esters is, in most cases, the ring hydrogenation of the corresponding aromatic polycarboxylic acid esters, such as the above-mentioned phthalates. For this purpose, many methods are known to those skilled in the art. For example, Patent Document 1 discloses a method for continuous catalytic hydrogenation in at least two reactors connected in series, and the catalyst volume is kept as low as possible. The first reactor is operated in a loop mode, and at least one additional reactor is operated in a straight-through mode. During the continuous hydrogenation process, the temperature rises at the outlet of the first reactor operated in a loop mode. If it is supplied to a reactor operated in a straight-through mode at the temperature reached here, there may be a situation where the temperature of the second reactor becomes too high and the reaction has to be stopped.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Accordingly, an object of the present invention is to provide a method for the catalytic hydrogenation of aromatic compounds, preferably aromatic polycarboxylic acids and their esters, which has a high yield and enables the temperature of the second reactor to be controlled.

Means for Solving the Problems

[0007] This problem is a method for producing one or more alicyclic compounds, comprising the following: (i) providing a stream A containing one or more aromatic compounds and a hydrogen-containing hydrogenation gas; (ii) feeding the stream A to a first hydrogenation unit at a temperature T1 to hydrogenate the one or more aromatic compounds to obtain the corresponding alicyclic compounds; (iii) obtaining a mixture as a first product stream at a temperature T2, containing the aromatic compounds and the alicyclic compounds; (iv) separating the product stream obtained in (iii) into a partial stream, feeding this to the stream A in (i), and hydrogenating it again as a part of the stream A in (ii), where a further partial stream is fed as stream B at a temperature T3 to one or more further hydrogenation units; (v) hydrogenating the aromatic compounds contained in the stream B in the one or more further hydrogenation units to obtain the corresponding alicyclic compounds; and (vi) obtaining a second product stream at a temperature T4, containing one or more alicyclic compounds corresponding to the one or more aromatic compounds fed in (i). A method comprising, wherein This was achieved by providing a method in which the temperature T2 is not equal to the temperature T3, or the temperature T2 is higher than the temperature T3.

[0008] In the context of the present invention, the term "alicyclic compound" is understood to mean a compound having a saturated ring system with an aliphatic structure. 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.

[0009] In the context of the present invention, the term "aromatic compound" is understood to mean a compound having at least one ring system containing 4n + 2 delocalized electrons in accordance with Hückel's rule, in 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.

[0010] In the context of the present invention, the term "hydrogen-containing hydrogenation gas" is a gas containing hydrogen. Hydrogen is used as another reactant in addition to the aromatic compound within the scope of the reaction on which the present invention is based. 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 the electron-rich multiple bond (double bond). Hydrogenation is carried out when two hydrogen atoms are formally converted into a 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 catalyst poisons such as carbon monoxide or hydrogen sulfide in harmful amounts. In some cases, it is preferable to use hydrogen with a purity of more than 95%, particularly more than 98%, of an inert gas. The inert gas component may be, for example, nitrogen or methane. The amount of hydrogen present in the hydrogenation unit is preferably present in an excess amount, particularly an excess of 1% to 200%, preferably 3% to 100%, particularly preferably 5% to 50%, relative to the stoichiometric amount necessary for this hydrogen to achieve the possible or desired conversion in the hydrogenation unit. Adding a sufficiently excessive amount of hydrogen can be advantageous for the complete hydrogenation of aromatic bonds.

[0011] Each hydrogenation unit can be supplied with fresh hydrogen. However, in order to minimize the consumption of hydrogen and the discharge loss associated with the exhaust gas, it is convenient to use the exhaust gas from one hydrogenation unit as the hydrogenation gas for another hydrogenation unit or the same hydrogenation unit. Furthermore, the exhaust gas from the hydrogenation unit can be reused as fresh hydrogen after treatment. For example, in a process carried out in two hydrogenation units connected in series, it is advantageous to supply fresh hydrogen to the first hydrogenation unit and send the exhaust gas from the first hydrogenation unit into the second hydrogenation unit. In this case, the reactants and the hydrogenation gas flow through the hydrogenation units in the reverse order. In this process, it is advantageous to keep the hydrogen excess below 30%, particularly below 20%, based on the stoichiometric requirement. The term "hydrogenation unit" in the context of the present invention is understood as a hydrogenation reactor, or a group of reactors consisting of a plurality of reactors connected in series, a plurality of reactors connected in parallel, or reactors connected in parallel and in series. That is, in the process according to the present invention, it is understood as a reactor or a reactor arrangement that can perform the function as a reactor.

[0012] In the context of the present invention, the term "recycle (reuse)" or "loop type" means recycling at least partially the product stream of a hydrogenation unit as part of the input stream to the same hydrogenation unit. This may involve splitting the product stream or mixture obtained from the hydrogenation unit. This means that a partial stream of the hydrogenation effluent (output) or product stream of the first hydrogenation unit is sent as stream A together with fresh reactants to the first hydrogenation unit. Another partial stream of the hydrogenation effluent or product stream of the first hydrogenation unit is preferably hydrogenated in a second hydrogenation unit operated in a once-through mode. Instead of one large loop-type hydrogenation unit, two or more smaller units arranged in series or in parallel may be used. Also, instead of one large hydrogenation unit with a linear through-flow, a plurality of units connected in series or in parallel may be operated. However, it is preferred to use only one hydrogenation unit operated in a loop type and only one unit operated in a once-through mode. This method may be carried out in a tube bundle reactor.

[0013] In the context of the method according to the present invention, in step (iv), it is preferably carried out with a recycle ratio of 1:10 to 1:50, preferably 1:10 to 1:40, particularly preferably 1:30. When this ratio is 1:10, for example, it means that 10 tons of the first product stream is sent back to the top of the first hydrogenation unit and 1 ton is supplied to at least one further hydrogenation unit. The recycle ratio is adjusted such that a conversion rate of 80% to 99%, preferably 85% to 97%, is achieved in the first unit of the hydrogenation units connected in series and a conversion rate of 80% to 100%, preferably 85% to 100%, is achieved in the second hydrogenation unit, based on the initial concentration of the compound to be hydrogenated at the inlet of each hydrogenation unit. When using three or more hydrogenation units, the conversion needs to be adjusted accordingly.

[0014] At least one additional hydrogenation unit can be operated in a loop or straight-through mode, i.e., the recycle is not returned to the same hydrogenation unit. At least one additional hydrogenation unit is preferably operated in a straight-through mode. Hydrogenation can be carried out in the absence of a solvent or, preferably, in the presence of a solvent. Any liquid that forms a homogeneous solution with the reactants and products, is inert under the hydrogenation conditions, and can be easily separated from the product can be used as the solvent. The solvent can also be a mixture of a plurality of substances and may contain water. For example, the following substances: linear or cyclic ethers such as tetrahydrofuran and dioxane, and aliphatic alcohols having 1 to 13 carbon atoms in the alkyl group can be used as the solvent. Preferred alcohols are isopropanol, n-butanol, isobutanol, n-pentanol, 2-ethylhexanol, nonanol, industrial nonanol mixture, decanol, industrial decanol mixture, tridecanol. When using an alcohol as the solvent, it may be convenient to use the alcohol or alcohol mixture formed by the hydrolysis of the product. This eliminates the formation of by-products by transesterification. A more preferred solvent is the hydrogenation product itself.

[0015] By using a solvent, the concentration of aromatic compounds in the feed to the reactor can be limited, so that the temperature in the reactor can be better controlled. Thereby, side reactions can be minimized and the product yield can be increased. Preferably, the concentration of aromatic compounds in the reactor feed is 1 to 35% by mass, particularly 5 to 25% by mass, based on the total amount of reactants used. In a reactor operated in a loop mode, the required concentration range can be adjusted by the circulation ratio (the ratio of the recycled hydrogenation effluent to the amount of reactants).

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

DETAILED DESCRIPTION OF THE INVENTION

[0017] Regarding the method of the present invention, in step (i), a stream A containing one or more aromatic compounds and a hydrogen-containing hydrogenation gas is provided as a reactant. Here, the new reactant is supplied to the input stream and sent to the first hydrogenation unit through the input stream. The input stream (2b) is at a temperature T1. Subsequently, in this first hydrogenation unit (1), the hydrogenation in step (ii) is carried out. In step (iii), at the end of the hydrogenation unit, a mixture containing a hydrogenated compound (alicyclic compound) and a non-hydrogenated compound (aromatic compound) is obtained as the first product stream. In a preferred embodiment, the product stream from the first hydrogenation unit is sent to subsequent process steps by a pump. Here, a commercially available pump can be used. Suitable pumps are known to those skilled in the art. The temperature of the mixture or the first product stream is T2. Then, in step (iv), it is separated into two partial streams. At this time, one partial stream is supplied to stream A and further hydrogenated in step (ii) together with the new reactant in the first hydrogenation unit. The second partial stream is introduced as stream B into the second hydrogenation unit and the temperature is T3. This is hydrogenated in at least one additional hydrogenation unit in step (v). As a result, the reactants that were not converted in the first hydrogenation unit are hydrogenated to the corresponding alicyclic compounds in this second hydrogenation unit. The temperature of the product mixture obtained as a stream in step (vi) is T4.

[0018] The separation in step (vi) of the method according to the present invention is preferably carried out on a known T-shaped component of the pipeline. Here, valves are advantageously arranged at both ends of the T-shaped component in order to control the mass flow rate and thus the separation.

[0019] Within the scope of the present invention, when adjusting the outlet temperature T2 of the first hydrogenation unit and the inlet temperature T3 of at least one further hydrogenation unit independently of each other, it has been found that the time yield of the process can be increased and the temperature in at least one further hydrogenation unit can be controlled.

[0020] In the second product stream at the outlet of at least one further hydrogenation unit, the aromatic compound used as a reactant preferably 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. Preferably, process parameters such as the concentrations of the product, by-products, reactants, temperature, etc. are determined by on-line analysis. The on-line analysis preferably acquires each parameter in real time in the product discharge stream of the first hydrogenation unit (3) and / or each further hydrogenation unit (12). Preferably, a measuring method selected from the group consisting of a reaction calorimeter, ATR-FTIR spectroscopy, Raman spectroscopy, IR spectroscopy, UV and / or UV-VIS spectroscopy or a combination thereof is used. This setting can also be carried out in an automated manner, that is, using computer technology.

[0021] In connection with the present invention, it is preferable to hydrogenate the aromatic compound obtained in step (i) using the hydrogen-containing gas obtained in step (i). The aromatic compound is provided together with the product obtained in step (i) on one or more solid catalysts arranged in the fixed bed of the hydrogenation unit.

[0022] Furthermore, the solid catalyst preferably contains at least one metal of subgroup 8 of the periodic table of the elements. Preferably, platinum, rhodium, palladium, cobalt, nickel or ruthenium or a mixture of two or more thereof is used as the active metal, and particularly ruthenium is used as the active metal. In addition to the metals already mentioned, at least one metal of subgroup 1 and / or subgroup 7 of the periodic table of the elements may be included in the catalyst. Preferably, a metal of subgroup 8 of the periodic table of the elements and rhenium and / or copper are used.

[0023] The catalyst used in this process is preferably the said metal advantageously applied on a support material. Preferably, the support material used is a material containing micropores (micropores; pore diameter less than 2 nm), mesopores (mesopores; pore diameter 2 - 50 nm) and macropores (macropores; pore diameter greater than 50 nm). For example, regarding the types of pores, the following combinations of pores: a) Mesopores only b) Micropores and mesopores c) Mesopores and macropores d) Micropores, mesopores and macropores e) Micropores and macropores There are support materials that can be used.

[0024] Preferably, as the support material, 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. Preferably, as the support material, a solid that is sufficiently inert under hydrogenation conditions is used. For example, activated carbon, silicon carbide, silicon dioxide, titanium dioxide and / or zirconium dioxide, and mixtures of these compounds can be mentioned. Titanium dioxide is particularly preferred as the support material. Titanium dioxide exists in three forms (anatase, rutile and brookite), among which anatase and rutile are the most common. A preferred support material is Aerolyst 7711 (registered trademark) (Evonik Operations GmbH). The said support material is composed of 15 - 20% by mass of rutile and 80 - 85% by mass of anatase. Further suitable titanium dioxide support materials include those produced based on titanium dioxide from the sulfuric acid process. They usually contain 98% or more of anatase.

[0025] The solid catalyst used for the hydrogenation in step (ii) and / or step (v) is particularly preferably a catalyst containing ruthenium as the only metal and titanium dioxide as the carrier material. In a preferred embodiment, the catalysts used for the hydrogenation in step (ii) and / or step (v) are the same, and particularly preferably, it is a catalyst containing ruthenium as the only metal and titanium dioxide as the carrier material.

[0026] In the process according to the invention, the hydrogenation in step (ii) and / or step (v) is carried out in the liquid phase or the gas phase. The hydrogenation can be carried out continuously or discontinuously on a suspended catalyst or a massive catalyst arranged in a fixed bed. In the process according to the invention, preferably, it is a continuous hydrogenation on a catalyst arranged in a fixed bed where the product / reactant phase is mainly in the liquid state under the reaction conditions.

[0027] Preferably, the hydrogenation in step (ii) and / or step (v) is carried out at a pressure of 3 to 300 bar, preferably 15 to 200 bar, particularly preferably 50 to 150 bar.

[0028] More preferably, the hydrogenation in step (ii) and / or step (v) is carried out at a temperature of 50°C to 250°C, preferably 70 to 200°C. This temperature is in the discharge stream (T2 and T4) of the hydrogenation unit after the hydrogenation is carried out. Since the hydrogenation reaction is an exothermic reaction, the reaction does not occur at a fixed temperature but within the temperature range described herein. Therefore, the temperature of the reaction mixture increases as it passes through the hydrogenation unit.

[0029] According to the present invention, the temperature T2 is not equal to the temperature T3, and preferably, the temperature T2 is higher than the temperature T3. In the present invention, it has been found that it is advantageous not to directly supply the product stream at temperature T2 to at least one further hydrogenation unit, but to cool it and supply it to at least one further hydrogenation unit at a lower temperature T3. Therefore, particularly preferably, the temperature T2 of the obtained mixture is higher than the temperature T3 of the mixture supplied to the hydrogenation unit in step (iv).

[0030] Temperature control (T2 ≠ T3, preferably T2 > T3) can be achieved by arranging a cooling device for cooling at least a part of the discharge stream between the discharge stream of the first hydrogenation unit, i.e., the first product stream, and the input stream of the second hydrogenation unit, in the input stream to at least one further hydrogenation unit, to achieve a temperature T3 different from the temperature T2. Preferably, the cooling is achieved by a heat exchanger. The related devices are well known to those skilled in the art. To utilize the extracted thermal energy at other locations in the process or in a network of multiple systems, preferably a heat exchanger is used.

[0031] Therefore, the discharge stream or the first product stream from the hydrogenation in step (ii) may be cooled after exiting the first hydrogenation unit, i.e., the first product stream may be cooled before being separated in step (iv), but only the part of the discharge stream sent to at least one further hydrogenation unit / the second hydrogenation unit may be cooled, i.e., cooling may be performed here after the separation in step (iv). In the present invention, it is preferred that the first product stream is cooled before being separated in step (iv). In this case, it is particularly preferred that a bypass is provided in the process through which a part of the first product stream from the first hydrogenation unit can be mixed with stream B via a side stream before cooling. Therefore, the non-cooled part of the first product stream may be mixed with stream B to increase the temperature T3. As a result, the temperature T3 can be adjusted independently of the cooling and independently of the temperature of stream A.

[0032] In the context of the method according to the present invention, one or more aromatic carboxylic acid esters, preferably one or more aromatic mono-, di- and polycarboxylic acid esters, are provided in step (i). In the method according to the invention, aromatic compounds such as aromatic polycarboxylic acids and / or aromatic monocarboxylic acids or derivatives thereof, in particular their alkyl esters, can be converted into the corresponding alicyclic polycarboxylic acid compounds. Both complete esters and partial esters can be hydrogenated. A complete ester is 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 method according to the invention, they preferably have 2, 3 or 4 ester functional groups.

[0033] In the context of the method according to the invention, in step (i), one or more benzene, diphenyl, naphthalene, diphenyl oxide, anthracene dicarboxylic acid esters or polycarboxylic acid esters are provided. The alicyclic polycarboxylic acid or its derivative obtained by the method of the invention optionally consists of one or more C6 rings linked or fused by carbon-carbon bonds.

[0034] In step (i), preferably, one or more aromatic carboxylic acid esters 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, preferably C8-C10 phthalates, C8-C10 terephthalates, C8-C10 isophthalates and C8-C10 trimellitates, particularly preferably di-2-ethylhexyl phthalate, diisononyl phthalate, di-2-ethylhexyl terephthalate, diisononyl terephthalate, di-2-ethylhexyl isophthalate, triisononyl isophthalate, di-2-ethylhexyl trimellitate and triisononyl trimellitate are provided. Here, C8 preferably means 2-ethylhexyl or n-octyl, C9 means isononyl, and C10 means isodecyl or 2-propylheptyl.

[0035] The method is preferably a method 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, that is, 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 formed.

[0036] In the method according to the invention, for example, the following esters of aromatic carboxylic acids 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, acids formed from the above acids may be used by substituting one or more hydrogen atoms bonded to the aromatic ring with alkyl, cycloalkyl or alkoxyalkyl groups. Preferably, alkyl, cycloalkyl and alkoxyalkyl esters of the above acids are used. For example, these groups are each independently, containing 1 to 25 carbon atoms, particularly 3 to 15 carbon atoms, very particularly 8 to 13 carbon atoms, especially 9 carbon atoms. These groups may be straight-chain or branched-chain. When there are a plurality of ester groups in the reactant, these groups may be the same or different.

[0037] Compounds such as the following can be mentioned as esters of aromatic polycarboxylic acids in the method of the present invention: 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, diisononyl terephthalate, di-2-propylheptyl terephthalate, di-n-decyl terephthalate, di-n-undecyl terephthalate, diisodecyl terephthalate, diisododecyl terephthalate, ditridecyl terephthalate, di-n-octadecyl terephthalate, diisooctadecyl ester 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 phthalate, di-n-nonyl phthalate, diisononyl phthalate, di-n-decyl phthalate, di-2-propylheptyl ester, diisodecyl phthalate, di-n-undecyl phthalate, diisoundecyl phthalate, ditridecyl phthalate, di-n-octadecyl phthalate, diisooctadecyl phthalate, di-n-eicosyl terephthalate, monocyclohexyl phthalate; 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, monocyclohexyl isophthalate.

[0038] The method of the present invention can in principle also be applied to benzoic acid and its esters. These include 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 consist of 1 to 25, preferably 8 to 13, and each may be straight-chain or branched-chain. On an industrial scale, aromatic esters, especially all esters, are often preferably produced from alcohol mixtures. Examples of suitable alcohol mixtures include the following. A C5 alcohol mixture produced by hydroformylation and subsequent hydrogenation from linear butenes; a C5 alcohol mixture produced by hydroformylation and subsequent hydrogenation from a butene mixture containing linear butenes and isobutene; a C6 alcohol mixture produced by hydroformylation and subsequent hydrogenation from pentene or a mixture of two or more pentenes; a C7 alcohol mixture produced by hydroformylation and subsequent hydrogenation from the trimerization of ethylene or the dimerization of propylene or a hexene isomer or another mixture of hexene isomers; a C8 alcohol mixture such as 2-ethylhexanol (two isomers), produced by aldol condensation of n-butyl aldehyde and subsequent hydrogenation; a C9 alcohol mixture produced by dimerization, hydroformylation and hydrogenation from C4 olefins. To produce C9 alcohols, it is possible to start from isobutene, or from a mixture of linear butenes, or from a mixture of linear butenes and isobutene. C4 olefins can be dimerized using various catalysts such as protonic acids, zeolites, organometallic nickel compounds or solid nickel-containing catalysts. The hydroformylation of C8 olefin mixtures can be carried out using a rhodium catalyst or a cobalt catalyst. Thus, there are various industrial C9-alcohol mixtures; a C10-alcohol mixture produced by hydroformylation and subsequent hydrogenation from tripropylene; 2-propylheptanol (two isomers) produced by aldol condensation of valeraldehyde and subsequent hydrogenation; a C10-alcohol mixture produced by aldol condensation and subsequent hydrogenation from at least two C5-aldehydes; a C13-alcohol mixture produced by hydroformylation and subsequent hydrogenation from hexaethylene, tetrapropylene or tributene.

[0039] Other alcohol mixtures can be obtained, for example, by hydroformylation and subsequent hydrogenation from olefins or olefin mixtures resulting from Fischer-Tropsch synthesis, dehydrogenation of hydrocarbons, metathesis reactions, polygas processes, or other technical processes. Furthermore, alcohol mixtures can be produced using olefin mixtures containing olefins with different numbers of carbon atoms.

[0040] In the method of the present invention, any ester mixture produced from an aromatic polycarboxylic acid and the above alcohol mixture can be used. According to the present invention, it is preferable to use esters produced from phthalic acid or phthalic anhydride and terephthalic acid or dimethyl terephthalate and a mixture of isomeric alcohols having 4 to 13 carbon atoms. Preferably, the following steps: (i) Providing a stream A comprising one or more aromatic compounds selected from the group consisting of esters of phthalic acid, isophthalic acid, terephthalic acid and / or trimellitic acid, particularly preferably selected from the group consisting of 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) Supplying the stream A to a first hydrogenation unit at a temperature T1 to hydrogenate the one or more aromatic compounds to obtain the corresponding alicyclic compounds; (iii) obtaining a mixture as a first product stream at a temperature T2, the mixture comprising the aromatic compound and an alicyclic compound selected from the group consisting of dialkyl cyclohexane-1,2-dicarboxylate, dialkyl cyclohexane-1,3-dicarboxylate, dialkyl cyclohexane-1,4-dicarboxylate and cyclohexane-1,2,4-tricarboxylate, particularly preferably 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, 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; (iv) separating the product stream obtained in (iii) into sub-streams, feeding this to stream A in (i), and re-hydrogenating it as a part of stream A in (ii), where a sub-stream is fed as stream B at a temperature T3 to one or more further hydrogenation units; (v) hydrogenating the aromatic compound contained in stream B in the one or more further hydrogenation units to obtain the corresponding alicyclic compound; and (vi) 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 1,2,4-trimellitic acid esters, particularly preferably 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, 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 corresponding to the one or more aromatic compounds supplied in (i) above, to obtain a second product stream at a temperature of T4; A method for producing one or more alicyclic compounds comprising, wherein the temperature T2 is not equal to the temperature T3, or the temperature T2 is higher than the temperature T3.

[0041] The alicyclic compounds present in the second product stream depend on the reactants used. For example, when diisononyl phthalate is used as the starting material, diisononyl cyclohexane-1,2-dicarboxylate is obtained as the product.

[0042] [[ID=]](10) Particularly preferred is a method for producing one or more alicyclic compounds, as follows: (i) Providing a stream A containing diisononyl phthalate (DINP) or di-2-ethylhexyl phthalate (DEHP) and a hydrogen-containing hydrogenation gas; (ii) Supplying the stream A at temperature T1 to a first hydrogenation unit to hydrogenate the one or more aromatic compounds to obtain corresponding alicyclic compounds; (iii) Obtaining a mixture as a first product stream at temperature T2, which contains diisononyl cyclohexane-1,2-dicarboxylate (DINCH) or di-2-ethylhexyl cyclohexane-1,2-dicarboxylate (DEHCH); (iv) Separating the product stream obtained in (iii) into a partial stream, supplying this to the stream A in (i), and again hydrogenating it as a part of the stream A in (ii), where a partial stream is supplied as stream B at temperature T3 to one or more further hydrogenation units; (v) Hydrogenating the aromatic compounds contained in the stream B in the one or more further hydrogenation units to obtain corresponding alicyclic compounds; and (vi) Obtaining a second product stream at temperature T4, which contains diisononyl 1,2-cyclohexanedicarboxylate (DINCH) or di-2-ethylhexyl 1,2-cyclohexanedicarboxylate (DEHCH); A method comprising, wherein the temperature T2 is not equal to the temperature T3, or the temperature T2 is higher than the temperature T3.

[0043] Particularly preferred is further a method for producing one or more alicyclic compounds, comprising the following: (i) Providing a stream A containing diisononyl terephthalate or di-2-ethylhexyl terephthalate and a hydrogen-containing hydrogenation gas; (ii) Supplying the stream A at temperature T1 to a first hydrogenation unit to hydrogenate the one or more aromatic compounds to obtain one or more corresponding alicyclic compounds; (iii) Obtaining a mixture as a first product stream at temperature T2, which contains diisononyl cyclohexane-1,4-dicarboxylate or di-2-ethylhexyl cyclohexane-1,4-dicarboxylate; (iv) Separate the product stream obtained in (iii) into sub-streams, supply this to stream A in (i), and re-hydrogenate it as part of stream A in (ii), where a sub-stream is supplied as stream B at temperature T3 to one or more further hydrogenation units; (v) Hydrogenate the aromatic compounds contained in stream B in the one or more further hydrogenation units to obtain the corresponding alicyclic compounds; and (vi) Obtain a second product stream at temperature T4 containing diisononyl cyclohexane-1,4-dicarboxylate or di-2-ethylhexyl cyclohexane-1,4-dicarboxylate; A method comprising, wherein The temperature T2 is not equal to the temperature T3, or the temperature T2 is higher than the temperature T3.

[0044] Particularly preferred is further a method for producing one or more alicyclic compounds, comprising the following: (i) Providing a stream A comprising triisononyl trimellitate (TINTM) or tri-2-ethylhexyl trimellitate (TOTM) and a hydrogen-containing hydrogenation gas; (ii) Supplying stream A at temperature T1 to a first hydrogenation unit to hydrogenate the one or more aromatic compounds to obtain the corresponding alicyclic compounds; (iii) Obtaining a mixture as a first product stream (3) at temperature T2 comprising triisononyl cyclohexane-1,2,4-tricarboxylate or tri-2-ethylhexyl cyclohexane-1,2,4-tricarboxylate; (iv) Separate the product stream obtained in (iii) into sub-streams, supply this to stream A in (i), and re-hydrogenate it as part of stream A in (ii), where a sub-stream is supplied as stream B (9) at temperature T3 to one or more further hydrogenation units; (v) Hydrogenate the aromatic compounds contained in stream B in the one or more further hydrogenation units to obtain the corresponding alicyclic compounds; and (vi) Obtaining a product stream (12) at a temperature T4, containing triisononyl cyclohexane-1,2,4-tricarboxylate or tri-2-ethylhexyl cyclohexane-1,2,4-tricarboxylate; A method comprising, wherein said temperature T2 is not equal to said temperature T3, or said temperature T2 is higher than said temperature T3.

[0045] The method according to the invention is preferably carried out under the following conditions. In the feed of the first hydrogenation unit (loop type), the concentration of the aromatic compound as a reactant is 5 to 30% by mass, particularly 8 to 15% by mass. In the effluent stream of the first hydrogenation unit, the concentration of the reactant is 0.3 to 8% by mass, particularly 1.5 to 4% by mass. The specific liquid hourly space velocity (LHSV, catalyst loading, liters of fresh reactant per liter of catalyst per hour) in the first hydrogenation unit is 0.1 to 5 / hour, particularly 0.5 to 3 / hour. The surface area velocity in the first 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 first hydrogenation unit is 70 to 150 °C, particularly 80 to 120 °C. The hydrogenation pressure in the first hydrogenation unit is 25 to 200 bar, particularly 80 to 110 bar.

[0046] The liquid hourly space velocity (reactant liters / catalyst liters / hour) of the second hydrogenation unit is 1 to 8 / hour, particularly 2 to 5 / hour. In the second hydrogenation unit, the average temperature is 70 to 150 °C, particularly 80 to 120 °C. The hydrogenation pressure in the second hydrogenation unit is 25 to 200 bar, particularly 80 to 100 bar.

[0047] This variant method is particularly suitable for the hydrogenation of phthalic esters, in particular diisononyl phthalate (as the isomer mixture "diisononyl phthalate", for example VESTINOL 9 from OXENO GmbH) or di-2-ethylhexyl phthalate.

[0048] A further aspect of the invention is the provision of an apparatus for carrying out the method according to the invention, said apparatus comprising a first hydrogenation unit and one or more further hydrogenation units and one or more heat exchangers, wherein the heat exchanger is arranged such that the discharge stream is sent to the heat exchanger via the input stream, the temperature of the discharge stream of the heat exchanger is lower than the input stream, and then it is supplied as an input stream to a further hydrogenation unit via a pipeline and / or is supplied to one or more further hydrogenation units via a stream and / or is supplied to the input stream to the first hydrogenation unit via a stream, preferably the temperatures of the discharge stream and the input stream are different. Preferably, there may be at least one further heat exchanger, which is arranged, for example, in the input stream of at least one further hydrogenation unit.

[0049] For the apparatus according to the invention, the first hydrogenation unit and / or at least one hydrogenation unit has one or more fixed-bed catalysts, preferably said solid catalyst preferably contains at least one metal of subgroup 8 of the periodic table of the elements, particularly preferably ruthenium. A preferred support material is titanium dioxide. The description herein applies equally to the catalysts used.

[0050] Also, the pipeline of the first hydrogenation unit (1) is preferably arranged such that a part of the first product stream (2) of the first hydrogenation unit (1) can be mixed with stream B via a side stream before passing through the heat exchanger (3). As a result, a part of the non-cooled first product stream can be mixed with stream B to increase its temperature.

[0051] Present in one of the first hydrogenation unit and / or one or more additional hydrogenation units is a mixture of an aromatic compound and the corresponding alicyclic compound, or an aromatic carboxylic acid ester and their corresponding alicyclic compounds, and an alcohol component selected from the group consisting of branched or unbranched alkoxyalkyl, cycloalkyl and / or alkyl groups having 1 to 25 carbon atoms, preferably selected from C8-C10 phthalates, C8-C10 terephthalates, C8-C10 isophthalates and C8-C10 trimellitates, particularly preferably 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, diisononyl cyclohexanedicarboxylate and / or didecyl cyclohexanedicarboxylate, and their corresponding alicyclic compounds. The description herein applies equally to the reactants (aromatic compounds) and products (alicyclic compounds).

[0052] Within the scope of the present invention, preferably, the alicyclic polycarboxylic acid ester produced according to the present invention is used as a plasticizer for plastics. Preferred plastics are PVC, ethylene, propylene, butadiene, vinyl acetate, glycidyl acrylate, glycidyl methacrylate, acrylate, acrylate having an alkyl radical of a branched or unbranched alcohol having 1 to 10 carbon atoms bonded to the oxygen atom of the ester group, styrene, acrylonitrile, a homopolymer or copolymer of a cyclic olefin or a homopolymer or copolymer of a copolymer system thereof.

[0053] In addition to the above uses, the alicyclic polycarboxylic acid ester produced according to the present invention can be used as a component of lubricating oil, coolant and metalworking fluid. They can also be used as components of paints, varnishes, inks and adhesives.

Examples

[0054] Hereinafter, taking the structures shown in FIGS. 1 and 2 as examples, the process according to the present invention will be described. The embodiments shown in FIGS. 1 and 2 are exemplary embodiments that are not intended to limit the present invention. FIG. 1 shows an embodiment in which at least one aromatic compound and a hydrogen-containing hydrogenation gas are provided in step (i) and fed as a stream A through a product stream to a first hydrogenation unit (1). The temperature of stream A is T1. The hydrogenation in the subsequent step (ii) is carried out in this first hydrogenation unit (1). In step (iii), at the end of the hydrogenation unit (1), a mixture containing a hydrogenated compound (alicyclic compound) and a non-hydrogenated compound (aromatic compound) is obtained as a first product stream (2). The temperature of this mixture or the first product stream (2) is T2 and is preferably cooled by a cooling device (3), such as a heat exchanger (3). Thereafter, the cooled product stream is split into two partial streams in step (iv), and one of the partial streams is subjected to a hydrogenation treatment (possibly again) in the first hydrogenation unit (1) as a new product stream A. The second partial stream is sent as stream B to a second hydrogenation unit (4) at temperature T3. Hydrogen-containing hydrogenation gas from the first hydrogenation unit (1) is mixed into this stream B. This stream is hydrogenated in at least one further hydrogenation unit (4) in step (v), whereby reactants not converted in the first hydrogenation unit (1) are hydrogenated in this second hydrogenation unit (4) to form the corresponding alicyclic compounds. The temperature of the product mixture obtained as the second product stream (5) in step (vi) is T4. In this embodiment, a bypass can be provided, and using this bypass, a portion of the first product stream (2) from the first hydrogenation unit (1) can be mixed into stream B via a bypass stream indicated by a dashed arrow. Thereby, the temperature T3 can be set independently of cooling.

[0055] FIG. 2 shows an alternative embodiment that generally corresponds to the embodiment shown in FIG. 1. The only difference is that the first product stream (2) is sent to a cooling device or heat exchanger (3) using a pump (6). The product stream (5) at the outlet of the second hydrogenation unit (4) preferably 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 alicyclic compound used as the starting material.

[0056] Preferably, process parameters such as the concentrations and temperature of the product, by-products, and reactants are preferably determined by on-line analysis. The on-line analysis preferably records each parameter in real time in the product discharge stream of the first hydrogenation unit (1) and / or each further hydrogenation unit (4). Preferably, a measuring method selected from the group consisting of a reaction calorimeter, ATR-FTIR spectroscopy, RAMAN spectroscopy, IR spectroscopy, UV and / or UV-VIS spectroscopy, or a combination thereof is used. After determining the limit value based on the process parameters thus determined, the temperature T1 can be specifically set. This adjustment can be carried out automatically, that is, using computer technology.

[0057] Regarding the present invention, the hydrogenation of the aromatic compound provided in step (i) is preferably carried out on one or more solid catalysts arranged in the fixed bed of the hydrogenation unit using the hydrogen-containing gas provided in step (i). The solid catalyst more preferably contains at least one metal of Group 8 of the periodic table. Preferably, as the active metal, platinum, rhodium, palladium, cobalt, nickel or ruthenium or a mixture of two or more thereof is used, and particularly ruthenium is used as the active metal. In addition to the above-mentioned metals, at least one metal from Group 1 and / or Group 7 of the periodic table can also be included in the catalyst. Preferably, in addition to the metal of Group 8 of the periodic table, rhenium and / or copper are used.

Claims

1. A method for producing one or more alicyclic compounds, comprising the following: (i) providing a stream A comprising one or more aromatic compounds and a hydrogen-containing hydrogenation gas; (ii) supplying the stream A at a temperature T １ to a first hydrogenation unit to hydrogenate the one or more aromatic compounds to obtain corresponding alicyclic compounds; (iii) obtaining a mixture as a first product stream having a temperature of T and containing the aromatic compound and the alicyclic compound; ２ ​ (iv) Separating the first product stream obtained in (iii) into sub-streams, supplying this to stream A in (i), and re-hydrogenating it as part of stream A in (ii), where a further sub-stream is supplied as stream B at temperature T ３ to one or more further hydrogenation units at; (v) hydrogenating the aromatic compounds contained in the stream B in the one or more additional hydrogenation units to obtain the corresponding alicyclic compounds; and (vi) a process for producing a mixture of one or more alicyclic compounds corresponding to the one or more aromatic compounds provided in (i), the process being carried out at a temperature of T ４ obtaining a second product stream which is A method comprising, wherein The temperature T ２ is not equal to the temperature T ３ or the temperature T ２ is higher than the temperature T ３ method.

2. The method according to claim 1, wherein the hydrogenation of the aromatic compounds supplied in (i) is carried out by reacting with the hydrogen-containing gas supplied in (i) on one or more solid catalysts disposed in the fixed bed of the first hydrogenation unit.

3. The method according to claim 1 or 2, wherein the solid catalyst comprises at least one metal of subgroup 8 of the periodic table or ruthenium.

4. The method according to any one of claims 1 to 3, wherein (ii) is carried out at a circulation ratio of 1:10 to 1:50, 1:10 to 1:40, or 1:

30.

5. The method according to any one of claims 1 to 4, wherein the hydrogenation in (ii) and / or (iv) is carried out at a pressure of 3 to 300 bar, 15 to 200 bar, or 100 to 200 bar.

6. The method according to any one of claims 1 to 5, wherein the hydrogenation in (ii) and / or (iv) is carried out at a temperature of 50°C to 250°C or 100 to 200°C.

7. The method according to any one of claims 1 to 6, wherein the first product stream is cooled before being separated in (iv).

8. The method according to claim 7, wherein a bypass is provided, and a portion of the first product stream can be mixed with stream B by the bypass before being cooled in the first hydrogenation unit.

9. The method according to any one of claims 1 to 8, wherein in (i), one or more aromatic carboxylic acid esters, or one or more aromatic mono-, di- and polycarboxylic acid esters are provided.

10. The method according to any one of claims 1 to 9, wherein in (i), one or more benzene-, diphenyl-, naphthalene-, diphenyl-, anthracene di- or -polycarboxylic acid esters are provided.

11. In (i), the following: One or more aromatic carboxylic acid esters 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, preferably C8-C10 phthalates, C8-C10 terephthalates, C8-C10 isophthalates and C8-C10 trimellitates, particularly preferably 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, provided by the method according to any one of claims 1 to 10.

12. An apparatus for carrying out the method according to any one of claims 1 to 11, comprising a first hydrogenation unit and one or more further hydrogenation units (4) and one or more heat exchangers (3), wherein the one or more heat exchangers (3) are arranged such that the first product stream (2) is sent to the heat exchanger (3), the temperature of the discharge stream of the heat exchanger (3) is lower than the temperature of stream A, and then it is partially supplied as stream B via a pipeline to a further hydrogenation unit (4).

13. One or more of the first hydrogenation unit (1) and / or one or more further hydrogenation units (4) have one or more fixed bed catalysts, preferably the one or more solid catalysts contain at least one metal of subgroup 8 of the periodic table or ruthenium, the apparatus according to claim 12.

14. The pipeline of the first hydrogenation unit (1) is arranged to mix a portion of the first product stream (2) of the first hydrogenation unit (1) with stream B via a bypass stream before passing through the heat exchanger (3), the apparatus according to claim 12 or 13.

15. Present in one of the first hydrogenation unit and / or one or more further hydrogenation units is a mixture of an aromatic compound and a corresponding alicyclic compound, or an aromatic carboxylic acid ester and their corresponding alicyclic compounds, and an alcohol component selected from the group consisting of branched or unbranched alkoxyalkyl, cycloalkyl and / or alkyl groups having 1 to 25 carbon atoms, preferably selected from C8-C10 phthalates, C8-C10 terephthalates, C8-C10 isophthalates and C8-C10 trimellitates, particularly preferably 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, the apparatus according to any one of claims 12 to 14.

Images