DE1052975B - Process for the production of terephthalic acid esters - Google Patents
Process for the production of terephthalic acid estersInfo
- Publication number
- DE1052975B DE1052975B DEI6104A DEI0006104A DE1052975B DE 1052975 B DE1052975 B DE 1052975B DE I6104 A DEI6104 A DE I6104A DE I0006104 A DEI0006104 A DE I0006104A DE 1052975 B DE1052975 B DE 1052975B
- Authority
- DE
- Germany
- Prior art keywords
- oxidation
- xylene
- oxidized
- terephthalic acid
- acid esters
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 6
- 150000003503 terephthalic acid derivatives Chemical class 0.000 title claims description 4
- 238000004519 manufacturing process Methods 0.000 title description 2
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 15
- 150000002148 esters Chemical class 0.000 claims description 15
- 230000003647 oxidation Effects 0.000 claims description 14
- 238000007254 oxidation reaction Methods 0.000 claims description 14
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 claims description 12
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 5
- 239000003054 catalyst Substances 0.000 claims description 5
- LPNBBFKOUUSUDB-UHFFFAOYSA-N p-toluic acid Chemical compound CC1=CC=C(C(O)=O)C=C1 LPNBBFKOUUSUDB-UHFFFAOYSA-N 0.000 claims description 5
- 239000008096 xylene Substances 0.000 claims description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 3
- 238000002425 crystallisation Methods 0.000 claims description 2
- 230000008025 crystallization Effects 0.000 claims description 2
- 230000032050 esterification Effects 0.000 claims description 2
- 238000005886 esterification reaction Methods 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims description 2
- 238000004821 distillation Methods 0.000 claims 1
- 238000006266 etherification reaction Methods 0.000 claims 1
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 150000001298 alcohols Chemical class 0.000 description 6
- -1 toluic acid ester Chemical class 0.000 description 4
- KKEYFWRCBNTPAC-UHFFFAOYSA-N benzene-dicarboxylic acid Natural products OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 3
- 230000006698 induction Effects 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 150000008065 acid anhydrides Chemical class 0.000 description 2
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- WOZVHXUHUFLZGK-UHFFFAOYSA-N dimethyl terephthalate Chemical compound COC(=O)C1=CC=C(C(=O)OC)C=C1 WOZVHXUHUFLZGK-UHFFFAOYSA-N 0.000 description 2
- 239000005711 Benzoic acid Substances 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000010233 benzoic acid Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- VAYGXNSJCAHWJZ-UHFFFAOYSA-N dimethyl sulfate Chemical compound COS(=O)(=O)OC VAYGXNSJCAHWJZ-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- QSSJZLPUHJDYKF-UHFFFAOYSA-N methyl 4-methylbenzoate Chemical compound COC(=O)C1=CC=C(C)C=C1 QSSJZLPUHJDYKF-UHFFFAOYSA-N 0.000 description 1
- ZWLPBLYKEWSWPD-UHFFFAOYSA-N o-toluic acid Chemical compound CC1=CC=CC=C1C(O)=O ZWLPBLYKEWSWPD-UHFFFAOYSA-N 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000005809 transesterification reaction Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- 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
- C07C51/265—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 having alkyl side chains which are oxidised to carboxyl groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
- C07C67/313—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by introduction of doubly bound oxygen containing functional groups, e.g. carboxyl groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
Verfahren zur Herstellung von Terephthalsäureestern Zusatz zum Patent 969 994 Im Patent 969 994 ist ein Verfahren zur Ilerstellung von Terephthalsäureestern unter Verwendung von p-Xylol als Ausgangsstoff, wobei dieses gegebenenfalls unter Druck in Gegenwart von Katalysatoren mit Sauerstoff oder sauerstofihaltigen Gasen bei erhöhter Temperatur oxydiert wird, beschrieben, das in der Weise durchgeführt wird, daß die Oxydation, sobald sich ein noch Xylol enthaltendes, vorzugsweise aus Tolnylsäure bestehendes Oxydationsgemisch gebildet hat, unterbrochen wird, worauf dieses unmittelbar, vorzugsweise mit Methanol, verestert und das so erhaltene Estergemisch, gegEebenenfalls nach Zugabe von Frischxylol, weiteroxydiert wird.Process for the production of terephthalic acid esters. Patent addition 969 994 Patent 969 994 describes a process for the preparation of terephthalic acid esters using p-xylene as a starting material, this optionally under Pressure in the presence of catalysts with oxygen or gases containing oxygen is oxidized at elevated temperature, described, carried out in the way that the oxidation, as soon as a still containing xylene, preferably from Tolnylic acid has formed existing oxidation mixture, is interrupted, whereupon this directly, preferably with methanol, esterified and the ester mixture thus obtained, if necessary after adding fresh xylene, is further oxidized.
Bei der Durchführung des Verfahrens nach Patent 969 994 beobachtet man gelegentlich, daß die Oxydation des Toluylsäureesters zu Beginn außerordentlich träge verläuft und erst nach mehreren Stunden, manchmal sogar Tagen, mit normaler Geschwindigkeit, d. h. mit einer Geschwindite,keit, bei der die Oxydation des Toluylsäureesters zum Terephthalsäureester in wirtschaftlich tragbarer Weise verläuft. Es wurde nun gefunden, daß die Ursache für diese für den techni&chen Betrieb sehr störende Induktionsperiode in der Gegenwart von Hydroxylgruppen nthaltenden Verbindungen liegt, die dem Ester beigemischt sind, wenn dieser aus dem rohen oder nichl sorgfältig gereinigten Säuregemisch hergestellt wird, das bei der Oxydation des p-Xylols anfällt. Bei der Oxydation des p-Xylols entstehen neben der p-Toluylsäure auch deren Ester mit den als Partialoxydationsprodukte des p-Xylols auftretenden aromatischen Alkoholen. Bei der Veresterung der p-Toluylsäuren mit Alkoholen, insbesondere mit Mlethylalkohol, findet, da üblicherweise diese Alkohole in großem Überschuß angewandt werden, eine Umesterung der beigemischten Ester statt, so daß der in ihnen enthaltene Alkcyhol in Freiheit gesetzt wird. Es wurde nun festgestellt, daß die Anwesenheit dieser Alkohole die anlängliche Verzögerung der Oxydation der Ester bewirkt. Werden diese Alkohole beseitigt, so lassen sich die Ester ohne das Auftreten einer Induktionsperiode glatt oxydieren. Observed while performing the method according to patent 969,994 it is occasionally found that the oxidation of the toluic acid ester is extraordinary at the beginning runs sluggishly and only after several hours, sometimes even days, with normal Speed, d. H. with a speed at which the oxidation of the toluic acid ester to the terephthalic acid ester proceeds in an economically viable manner. It was now found that the cause for this is very disruptive for technical operation Induction period in the presence of compounds containing hydroxyl groups which are added to the ester, if this is carefully made from the raw or nichl Purified acid mixture is produced, which is obtained during the oxidation of p-xylene. When p-xylene is oxidized, not only p-toluic acid but also its esters are formed with the aromatic alcohols occurring as partial oxidation products of p-xylene. In the esterification of p-toluic acids with alcohols, especially with methyl alcohol, finds, since these alcohols are usually used in large excess, a Transesterification of the admixed esters takes place, so that the Alkcyhol contained in them is set free. It has now been determined that the presence of this Alcohols delay the oxidation of the esters. Will this If alcohols are eliminated, the esters can be removed without the occurrence of an induction period oxidize smooth.
Die den Estern beigemischten Alkohole können auf verschiedene Weise abgetrennt bzw. unschädlich gemacht werden. Je nach der Art des Esters kann die Abtrennung auf physikalischem Wege, z. B. durch Destillahon und/bzw. oder Kristallisation, vorgenommen werden. Man kann die Alkohole aber auch durch Überführun,g in Äther oder Ester unschädlich machten, z. B. durch längeres Erhitzen, gegebenenfalls in Gegenwart wasserabspaltender Mittel, wie Sehwefel-oder Phosphorsäure, durch Umsetzen mit Verät.herungsinitteln, wie Dimethylsulfat oder Veresterungsmitteln, z. B. Benzoesäure, Toluylsäure oder niederen aliphatischen Säuren oder Säureanhydriden, wie aromatisdien Säureanhydriden oder Essigsäureanhydrid. The alcohols added to the esters can be used in various ways separated or rendered harmless. Depending on the type of ester, the Separation by physical means, e.g. B. by Destillahon and / or. or crystallization, be made. The alcohols can also be converted into ether or rendered esters harmless, e.g. B. by prolonged heating, possibly in Presence of dehydrating agents, such as sulfuric or phosphoric acid, by reaction with Verät.herungsinigungen such as dimethyl sulfate or esterifying agents, e.g. B. benzoic acid, Toluic acid or lower aliphatic acids or acid anhydrides, such as aromatisdien Acid anhydrides or acetic anhydride.
In jedem Falle beobachtet man, daß, sobald die Hydroxylzafhl des zu oxydierenden Esters beseitigt ist, dieser ohne Induktionsperiode weiteroxydiert werden kann. Bei sehr kleinen Hydroxylzahlen (1 bis 5) kann die Oxydation durch Erhöhung der Katalysatormenge von üblicherweise 0,20/0 auf 0,5 bis 10/o in Gang gebracht werden; es ist daher auch möglich, die Hydroxylzahl auf derartige Werte zu erniedrigen und die Katalysatormenge entsprechend zu erhöhen.In any case it is observed that as soon as the hydroxyl number increases oxidizing ester is eliminated, this further oxidizes without an induction period can be. In the case of very small hydroxyl numbers (1 to 5), oxidation can occur Increase in the amount of catalyst from usually 0.20 / 0 to 0.5 to 10 / o in progress to be brought; it is therefore also possible to adjust the hydroxyl number to such values to lower and to increase the amount of catalyst accordingly.
Beispiel 1000 g eines bei der Oxydation von p-Xylol nach dem Hauptpatent angefallenen Gemisdies aus p-Toluylsäur.e und etwa 7 ovo Terephthalsäure, das mit 1000 cm3 Xylol gewaschen worden war, werden mit 2000 g Methanol unter Zusatz von 30 g Schwefelsäure in bekannter Weise verestert, überschüssiger Methylalkohol abdestilliert und nach dem Auswaschen der Schwefelsäure vom Terephthalsäuredimethylester abfiltriert. Der erhaltene p-Toluylsäuremethylester weist eine Hydroxylzahl von 12 auf. Example 1000 g of one in the oxidation of p-xylene according to the main patent Accrued Gemisdies from p-Toluylsäur.e and about 7 ovo terephthalic acid, which with 1000 cm3 of xylene had been washed with 2000 g of methanol with the addition of 30 g of sulfuric acid esterified in a known manner, excess methyl alcohol is distilled off and after washing out the sulfuric acid, the dimethyl terephthalate is filtered off. The methyl p-toluate obtained has a hydroxyl number of 12.
Werden 2 kg dieses Esters mit 0,2°/o vorlauffettsaurem Kobalt versetzt und bei 1400 C mit 1 kg Luft je Minute behandelt, so setzt die Oxydation nicht ein; innerhalb 24 Stunden steigt die SZ von 2,6 nur auf 3,9. Wird dagegen der Ester mit 2,5 Gewichtsprozent Essigsänreanhydrid versetzt und auf 1400 C erhitzt, so setzt die Oxydation unter denselben Bedingungen ohne wesentliche Verzögerung ein, denn nach 6 Stunden beträgt die SZ 29, nach 18 Stunden 72 und nach 21 Stunden 81. 0.2% cobalt is added to 2 kg of this ester and treated at 1400 C with 1 kg of air per minute, the oxidation does not start; within 24 hours, the AN increases from 2.6 to 3.9. If, on the other hand, the ester is with 2.5 percent by weight of acetic anhydride is added and the mixture is heated to 1400 ° C., it then sets the oxidation occurs under the same conditions without any significant delay, for after 6 hours the SZ is 29, after 18 hours 72 and after 21 hours 81.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEI6104A DE1052975B (en) | 1952-07-07 | 1952-07-07 | Process for the production of terephthalic acid esters |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEI6104A DE1052975B (en) | 1952-07-07 | 1952-07-07 | Process for the production of terephthalic acid esters |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE1052975B true DE1052975B (en) | 1959-03-19 |
Family
ID=7184944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DEI6104A Pending DE1052975B (en) | 1952-07-07 | 1952-07-07 | Process for the production of terephthalic acid esters |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE1052975B (en) |
-
1952
- 1952-07-07 DE DEI6104A patent/DE1052975B/en active Pending
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