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  • C07C2/04—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation
  • C07C2/06—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons by oligomerisation of well-defined unsaturated hydrocarbons without ring formation of alkenes, i.e. acyclic hydrocarbons having only one carbon-to-carbon double bond
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  • C07C2/42—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons homo- or co-oligomerisation with ring formation, not being a Diels-Alder conversion
  • C07C2/44—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by addition between unsaturated hydrocarbons homo- or co-oligomerisation with ring formation, not being a Diels-Alder conversion of conjugated dienes only
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  • C07C5/373—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen with simultaneous isomerisation
  • C07C5/393—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen with simultaneous isomerisation with cyclisation to an aromatic six-membered ring, e.g. dehydrogenation of n-hexane to benzene
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  • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
  • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
  • C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
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  • C12P5/00—Preparation of hydrocarbons or halogenated hydrocarbons
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  • C12P7/00—Preparation of oxygen-containing organic compounds
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  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/62—Carboxylic acid esters
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  • C07C2521/12—Silica and alumina
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  • C07C2523/14—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of germanium, tin or lead
• • C—CHEMISTRY; METALLURGY
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  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
  • C07C2523/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • C07C2523/18—Arsenic, antimony or bismuth
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  • C07C2523/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • C07C2523/24—Chromium, molybdenum or tungsten
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  • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
  • C07C2523/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • C07C2523/32—Manganese, technetium or rhenium
  • C07C2523/36—Rhenium

Definitions

• the present invention relates to a process for the preparation of terephthalic acid and terephthalic acid derivatives, preferably from renewable raw material sources.
• Terephthalic acid and its derivatives are important technical compounds that find numerous uses in chemistry.
• An important application is e.g. the use as a plasticizer, possibly also as a replacement of phthalic acid derivatives.
• a plasticizer possibly also as a replacement of phthalic acid derivatives.
• terephthalic acid esters e.g. As a substitution product for phthalic acid ester, a high isomeric purity of the terephthalic acid component is necessary. After conversion to the corresponding esters, particular relevant phthalate impurities would not be accepted by end users.
• terephthalic acid and its derivatives have been known for some time and, inter alia, in Baerns et. al. Technical Chemistry, 1st edition, Wiley-VCH, Weinheim 2006 described. Most of the time one starts from p-xylene, which is then oxidized to terephthalic acid and optionally further reacted.
• the xylene itself is produced, for example, from petroleum in refineries, but usually isomers are formed, which must be separated consuming.
• dimerization processes based on diisobutene are suitable, with a high isomeric purity of the diisobutene being important here, since otherwise xylene isomers are formed as well.
• renewable raw materials as starting materials for the production of organic chemicals on an industrial scale is becoming increasingly important.
• the resources based on crude oil, natural gas and coal are to be spared and, on the other, carbon dioxide is bound with renewable raw materials in a technically usable carbon source, which is in principle cost-effective and available in large quantities.
• Examples of the use of renewable raw materials for the industrial production of organic chemicals include u.a. the production of citric acid, 1,3-propanediol, L-lysine, succinic acid, lactic acid and itaconic acid.
• the object is to provide an alternative improved process for the preparation of terephthalic acid derivatives, preferably from renewable raw material sources available. It is of particular importance with regard to the preparation and use of terephthalic acid derivatives that as isomeric isobutene is preferably used for the preparation of the terephthalic acid derivatives.
• step d) conversion to terephthalic acid derivatives It has surprisingly been found that isobutene produced by fermentation is of such high purity with respect to linear butene isomers that the subsequent reaction yields p-xylene in high purity and yield. This in turn means that in step c) terephthalic acid also arises in high purity and thus possibly at the end of a highly isomerically pure terephthalic acid derivative.
• the by-product carbon dioxide formed in the fermentation and optionally further inerts may optionally be removed in a conventional manner by suitable separation methods.
• the reaction of isobutene to p-xylene can be carried out even without further purification of the isobutene, which is thus a preferred embodiment of the invention.
• the fermentative process according to the invention makes use of the high selectivity to isobutene as C4-01efm.
• carbon dioxide and other inerts do not interfere with the dimerization of isobutene to diisobutene as an intermediate step in the synthesis of para-xylene from isobutene. In special cases, however, it may prove expedient to first separate carbon dioxide and other inerts from the isobutene.
• isobutene either by means of microorganisms, preferably from renewable raw materials and / or in a cell-free enzymatic process, also preferably obtained from renewable raw materials.
• Isobutene is - as far as is known - not a natural product in the sense that it arises in metabolic processes in organisms in such quantities that an industrial use appears appropriate.
• isobutene is produced by naturally occurring microorganisms (US4698304, Fukuda, H. 1984 et al, From Agricultural and Biological Chemistry (1984), 48 (6), pp. 1679-82).
• the fermentative production of isobutene by means of modified, non-natural microorganisms or the correspondingly modified enzymes.
• Such microorganisms are known from US2011165644 (AI), which is treated in Example 13, the synthesis of isobutene from glucose in suitable microorganisms.
• WO2012052427 and WO2011032934 describe further enzymatic reactions which involve the formation of isobutene as a sequence of sequential enzymatic syntheses of
• this sequence of enzymatic syntheses described in I and II is included in a suitable microbial host organism capable of synthesizing acetone from metabolic precursors or transporting externally supplied acetone via the cell wall into the cell interior via passive or active transport, this can not be achieved -natural microorganism Isobutene can be produced with a fermentative process in good yield.
• Microorganisms that synthesize acetone from various carbohydrates have been known for a long time and are described i.a. in - Jones, T.D. and Woods, D.R. 1986, Microb. Reviews, pages 484 - 524 -. In - Taylor, D.G. et al., 1980, Journal of General Microbiology, 118, p. 159-170 describe microorganisms that use acetone as the sole source of carbon and thus are capable of transporting acetone across the cell wall into the cell interior.
• purification the following processes are understood in particular (but not limited to):
• the isobutene in step a) is obtained from trisaccharides, disaccharides, monosaccharides, acetone or mixtures thereof.
• the tri- and disaccharides used are, in particular, raffmose, cellobiose, lactose, isomaltose, maltose and sucrose.
• the monosaccharides used are, in particular, D-glucose, D-fructose, D-galactose, D-mannose, DL-arabinose and DL-xylose.
• the tri-, di- and monosaccharides are derived, inter alia (but not limited thereto) from the digestion and depolymerization of cellulose and hemicellulose by means of suitable methods; - directly from high-sugar plants such as sugar beet, sugar cane,
• the origin of the carbon atoms from renewable resource sources can be determined by the test method described in ASTM D6866. This is the Ratio of C to C carbon isotopes determined and compared with the isotope ratio of a reference substance whose carbon atoms come to 100% from renewable resources. This test method is also known in a modified form as the radiocarbon method and is described, inter alia, in Olsson, IU 1991, Euro Courses: Advanced Scientific Techniques, Volume 1, Issue Sei. Dating Methods, pages 15-35.
• the fermentation process is carried out at temperatures of> 20 ° C to ⁇ 45 ° C and under atmospheric pressure and releases isobutene as a gaseous product.
• This embodiment has the advantage that the isobutene thus obtained can be used further immediately or after separation of inerts.
• the fermentation process is carried out at temperatures of> 20 ° C to ⁇ 45 ° C and under pressure between 1 to 30 bar.
• isobutene can be obtained as a liquid compound and separated by phase separation directly from the fermentation medium. The separation of inerts can be greatly facilitated in this preferred embodiment.
• the conversion of isobutene to p-xylene can preferably be carried out in two ways:
• the reaction step b) is such that the isobutene produced by fermentation according to step a) is converted to para-xylene in a reaction step.
• this reaction also known as cyclodimerization, dehydrated amorphous silica gels treated with aluminum hydride (US 4384154), bismuth, lead or antimony oxides (US3644550 and US3830866), chromium oxide precipitated on alumina (US3836603) or rhenium or rhenium oxide deposited on a neutral or weakly acidic support material (US 4229320), are used as catalysts.
• this embodiment of the invention takes place between step a) and b) no purification of the isobutene, since the isobutene resulting from step a) is so pure that the cyclodimerization reaction is characterized by a high selectivity to para-xylene.
• reaction step b) is such that the isobutene produced by fermentation according to step a) is first dimerized to diisobutene in a step b1), which is subsequently reacted further in step b2) to give p-xylene becomes.
• diisobutene is understood to mean 2,4,4-trimethyl-1-pentene, 2,4,4-trimethyl-2-pentene as main components and any desired mixtures of these two compounds.
• step b1) is carried out under acid catalysis.
• sulfuric acid or acidic ion exchangers come into consideration, as described, inter alia, in Weissermel, Arpe, Industrial Organic Chemistry, VCH Verlagsgesellschaft, 3rd edition, 1988, p. 77; Hydrocarbon Processing, April 1973, p 171-173 are described.
• the methods described in US2004 / 0054246, US4100220 (A), US4447668 (A) and US5877372 (A) may be used.
• no purification of the diisobutene between step b1) and b2) takes place, in particular no purification for the removal of higher isobutene oligomers and optionally of inerts such as carbon dioxide and / or nitrogen.
• the process comprises a further step bl (i)), which is carried out according to bl): bl (i))
• Purification of the diisobutene preferably by distillation step bl (i)) is preferably carried out so that the unreacted volatile constituents be separated from the diisobutene and the resulting diisobutene is purified by distillation of the possibly formed in small amounts tri-isobutene and higher isobutene oligomers.
• Tri-isobutene thus obtained and the higher isobutene oligomers thus obtained can likewise be refined to give valuable secondary products.
• Step b2) is preferably carried out in a dehydrocyclization reaction.
• Such reactions and conditions for their implementation are in particular from WO
• step b2) is carried out in the presence of a catalyst.
• the catalysts are not finally selected from the group comprising bismuth, lead and antimony-containing catalysts, platinum catalysts, especially platinum deposited on Zeolite, chromium catalysts, especially chromium oxide precipitated on alumina and mixtures thereof.
• Step c) is preferably carried out in a liquid-phase oxidation.
• Oxidant is oxygen. Such methods are i.a. from A.K. Suresh, Ind. Eng.
• Step d) particularly preferably comprises an esterification, either mono- or di-esterification.
• Mono or diesters with aliphatic monoalkanols having 1 to 11 carbon atoms are preferred.
• the alcohols used are derived from renewable raw materials.
• alcohols can be used, whose production processes are described below:
• the fermentative production of straight-chain aliphatic monoalcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol and n-butanol is known in the art and has been operated on an industrial scale for decades.
• the fermentative production of branched-chain isopropanol and isobutanol is also known from the prior art (Sakuragi, H., Journal of Biomedical and Biotechnology, 2011, page 1-11).
• the synthesis of alpha-branched chain aliphatic monoalcohols from straight chain aliphatic monoalcohols by the Guerbet reaction is a method known in the art (Ullmann's Encyclopedia of Chemical Technology, 5th Ed., John Wiley & Sons, 1985, Vol.
• the preparation of 2-ethylhexanol can also be carried out by way of the partial oxidation of n-butanol produced from renewable raw material sources to n-butyraldehyde.
• 2-ethylhexanol can be obtained with all carbon atoms come to 100% from renewable resources.
• the catalytic partial oxidation of n-butanol to n-butyraldehyde is a method known in the art and is described e.g.
• the esterification (step d) can be carried out with stoichiometric amounts of terephthalic acid and aliphatic monoalcohol.
• the terephthalic acid is allowed to react with excess monoalcohol, which is generally the lower boiling component and which can be readily separated by distillation in the subsequent work-up of the crude ester.
• the aliphatic monoalcohol is used in a 10 to 50% molar, preferably in a 20 to 40% molar excess per mole of acid group to be esterified terephthalic acid.
• the reaction water formed is preferably distilled off in the course of the esterification reaction together with the excess monoalcohol from the reaction vessel and passed into a downstream phase separator, in which separate monoalcohol and water depending on their solubility.
• the monoalcohol used with water also forms an azeotrope under the reaction conditions and is capable of removing the water of reaction as entrainer. From the water attack can the Course of the reaction. The separated water is removed from the process while the monoalcohol from the phase separator flows back into the reaction vessel. Possibly.
• an azeotrope ie, another organic solvent, such as hexane, 1-hexene, cyclohexane, toluene, xylene, or xylene isomer mixtures may be added.
• the azeotrope former can be added at the beginning of the esterification reaction or after reaching higher temperatures. If the theoretically expected amount of water has accumulated or the acid number, for example determined in accordance with ASTM D 974, has fallen below a specified value, the reaction is usually terminated by allowing the reaction mixture to cool.
• the esterification of terephthalic acid can be carried out at atmospheric pressure, at reduced pressure or at elevated pressure, for example, to raise the esterification temperature.
• Lewis acids containing at least one element of groups 4 to 14 of the Periodic Table of the Elements are preferred, these can be used in solid or liquid form.
• the term "Lewis acid” in the context of the invention is understood to mean the generally customary definition of those elements or compounds which have an electron gap, as described for example in Römpp's Chemie-Lexikon, 8th edition, Franck'sche Verlags Stuttgart 1983, Volume 3, HL
• Particularly suitable Lewis acids which can be used as catalysts in the esterification reaction include titanium, zirconium, iron, zinc, boron, aluminum or tin, which are used as element in finely divided form or preferably in the form of compounds are, for example, tin (II) oxide, tin (IV) oxide, tin carboxylates, such as tin (II) 2-ethylhexanoate, tin (II) oxalate, tin (II)
• Suitable titanium compounds include alcoholates such as tetra (methyl) orthotitanate, tetra (ethyl) orthotitanate, tetra (propyl) orthotitanate, tetra (iso-propyl) orthotitanate, tetra (butyl) orthotitanate, tetra (iso-butyl) ortho-titanate Tetra (pentyl) orthotitanate or tetra (2-ethylhexyl) orthotitanate; Acylates, such as hydroxytitanium acetate, hydroxytitanium butyrate or hydroxytitanium pentanoate or chelates, such as tetraethylene glycol titanate or tetrapropylene glycol titanate.
• alcoholates such as tetra (methyl) orthotitanate, tetra (ethyl) orthotitanate, tetra (propyl) orthotitan
• the corresponding zirconium compounds can also be used successfully, such as tetra (methyl) orthozirconate, tetra (ethyl) orthozirconate, tetra (propyl) orthozirconate, tetra (isopropyl) orthozirconate, tetra (butyl) orthozirconate, tetra (isobutyl) orthozirconate , Tetra (pentyl) orthozirconate or tetra (2-ethylhexyl) orthozirconate.
• boric acid and boric acid esters such as trimethyl borate, triethyl borate, tri-propyl borate, triisopropyl borate, boric tributyl ester or triisobutyl borate.
• alumina aluminum hydroxide, aluminum carboxylates such as aluminum acetate or aluminum stearate, or aluminum alcoholates such as aluminum tri-butoxide, aluminum tri-sec-butoxide, aluminum tri-tert-butoxide or aluminum tri-iso-propylate.
• Zinc oxide, zinc sulfate and zinc carboxylates such as zinc acetate dihydrate or zinc stearate, and iron (II) acetate or iron (III) hydroxide oxide can also be used as catalysts.
• the catalyst can be added to the reaction mixture at the beginning or only later, taking into account safety measures at elevated temperature, for example, if the separation of the water of reaction has begun.
• the catalyst can also be added in portions.
• the amount of the esterification catalyst is lxlO "5 to 20 mol%, preferably 0.01 to 5 mol%, in particular 0.01 to 2 mol%, based on the in sub- weft added starting compound, expediently based on the terephthalic acid. At higher amounts of catalyst, depending on the application, cleavage reactions of the terephthalic acid esters can be expected.
• the addition of the esterification catalyst can be carried out in liquid or solid form. Solid catalysts, for example tin (II) oxide, zinc oxide or iron (III) hydroxide oxide are preferably filtered off after completion of the esterification reaction before the crude terephthalic acid ester is subjected to further workup.
• esterification catalysts are added as liquid compounds, for example tetra (iso-propyl) orthotitanate or tetra (butyl) orthotitanate, which are still dissolved in the reaction mixture after the esterification reaction has ended, these compounds are preferably rendered insoluble in the course of the workup process in the steam treatment filtered-off precipitates transferred.
• the esterification is carried out in the presence of an adsorbent. It uses porous, large-scale solid materials that are commonly used in chemical practice both in the laboratory and in technical equipment.
• adsorbent is finely suspended in the reaction solution, which is agitated by vigorous stirring or by introducing an inert gas. As a result, an intimate contact between the liquid phase and the adsorbent is achieved. The amount of adsorbent can be largely free and thus adjusted according to individual requirements.
• reaction mixture obtained after completion of the reaction usually contains in addition to the terephthalic acid ester as a desired reaction product optionally unreacted starting materials, in particular excess aliphatic monoalcohols, if according to the preferred embodiment of the method according to the invention with a monoalcohol excess is used.
• a monoalcohol excess is usually used.
• initially distilled unreacted and present in excess starting compounds expediently under application of a reduced pressure.
• the crude ester is preferably subjected to a treatment with steam, which can be carried out, for example, in a simple form by introducing steam into the crude product.
• a treatment with steam which can be carried out, for example, in a simple form by introducing steam into the crude product.
• An advantage of the steam treatment is that in its course still existing catalyst is destroyed and converted into easily filterable hydrolysis product. If the esterification reaction is carried out in the presence of an adsorbent, the adsorbent already present facilitates the separation of the catalyst by-products. Otherwise, it may prove advantageous to add the adsorbent at the beginning of the steam treatment.
• the presence of an adsorbent during the steam treatment also has an advantageous effect on the color and on the color stability of the terephthalic acid ester. But it is also possible to filter off the adsorbent after completion of the esterification reaction and separation of excess starting compounds, ie before carrying out the steam distillation.
• the steam treatment is generally carried out at atmospheric pressure, although the application of a slight negative pressure is expediently not excluded up to 400 hPa.
• the steam treatment is generally carried out at temperatures of 100 to 250 ° C, preferably from 150 to 220 ° C and in particular from 170 to 200 ° C and also depends on the physical properties of each produced terephthalic acid ester. In the process step of the steam treatment, it proves useful to proceed as gently as possible during the heating up to reach the working temperature in order to heat the crude ester to the required temperature for the steam treatment.
• a solid alkaline reactant such as basic silica, basic alumina or sodium carbonate, sodium bicarbonate, calcium carbonate, or sodium hydroxide in solid form, as well as basic minerals, further reduces the neutralization number of the terephthalic acid ester.
• the steam treatment is followed, if appropriate after filtration of the adsorbent, optionally added solid, alkaline substances and other accrued solids, the drying of the terephthalic acid ester, for example by passing an inert gas through the product at elevated temperature. It can also be applied at elevated temperature simultaneously a negative pressure and optionally an inert gas are passed through the product. Even without the action of an inert gas can be worked only at elevated temperature or only at lower pressure.
• the reaction is carried out at temperatures in the range of 80 to 250 ° C, preferably 100 to 180 ° C and at pressures of 0.2 to 500 hPa, preferably 1 to 200 hPa and especially 1 to 20 hPa not yet filtered, to free it from the solids, the optionally added solid alkaline reactants, the hydrolysis products of the catalyst and the adsorbent, if added in the esterification step or before the steam treatment.
• Filtration is preferably carried out in conventional filtration apparatuses at normal temperature or at temperatures up to 120 ° C. The filtration can be supported by common filtration aids such as cellulose, silica gel, kieselguhr, wood flour.
• light-colored terephthalic acid esters are usually obtained which also satisfy the other specifications, such as water content, residual acid content, residual content of catalyst components and residual content of monoester.
• linear or branched, aliphatic monoalcohols are used in the molecule.
• the process according to the invention can be carried out continuously or batchwise in the reaction apparatuses typical for the chemical industry.
• Rrockkessel or reaction tubes have proven to be useful, the batchwise reaction is the preferred.

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