EP0217897A1 - Procede de production de 2,5-dichlorphenol - Google Patents

Procede de production de 2,5-dichlorphenol

Info

Publication number
EP0217897A1
EP0217897A1 EP19860902391 EP86902391A EP0217897A1 EP 0217897 A1 EP0217897 A1 EP 0217897A1 EP 19860902391 EP19860902391 EP 19860902391 EP 86902391 A EP86902391 A EP 86902391A EP 0217897 A1 EP0217897 A1 EP 0217897A1
Authority
EP
European Patent Office
Prior art keywords
dichlorophenol
water
separated
weight
crystals
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.)
Withdrawn
Application number
EP19860902391
Other languages
German (de)
English (en)
Inventor
Joachim Falenski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
FALENSKI Joachim
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0217897A1 publication Critical patent/EP0217897A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
    • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
    • C07C37/70—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment
    • C07C37/84—Purification; separation; Use of additives, e.g. for stabilisation by physical treatment by crystallisation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C37/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
    • C07C37/68—Purification; separation; Use of additives, e.g. for stabilisation
    • C07C37/685—Processes comprising at least two steps in series

Definitions

  • the invention relates to a process for the preparation of 2,5-dichlorophenol with a content of 95 to over 99% from a mixture of about 80% 2,5-dichlorophenol, about 20% 2,4-dichlorophenol and minor other phenolic impurities by multi-stage Crystallization in the presence of water.
  • 2,5-dichlorophenol is of particular importance as a starting compound for the production of valuable agricultural chemicals.
  • German patent 1,493,493 now describes a method for separating this mixture with the aid of urea.
  • the 2,5-dichlorophenol is separated off via the water-insoluble urea adduct.
  • the process requires significant amounts of urea that are lost with the water. So it cannot be considered environmentally friendly. A recovery of the urea would be very expensive.
  • US Pat. No. 2,800,324 describes a process in which 1-bromo-2,5-dichlorobenzene is reacted with sodium hydroxide solution and methanol in an autoclave at elevated temperature and pressure in the presence of a copper catalyst and the reaction product is purified by extraction and distillation .
  • the process is complex and initially requires the production of 1-bromo-2,5-dichlorobenzene, which is generally associated with high costs.
  • the object of the invention is accordingly to provide an improved process for producing a largely pure 2,5-dichlorophenol.
  • the process should be simple to carry out and enable the separation of 2,4-dichlorophenol from its mixtures with 2,5-dichlorophenol in a more economical manner than is the case in the prior art.
  • This object is achieved according to the invention with a process for the preparation of 2,5-dichlorophenol, which is characterized in that a liquid mixture of about 8 parts by weight of 2,5-dichlorophenol and about 2 parts by weight of 2,4-dichlorophenol with hot water above the solidification temperature mixes, the crystals obtained after cooling are separated off, again transferred to the melt, mixed with hot water, cooled and the crystals which have separated out are separated off.
  • Mixtures of 2,5-and 2,4-dichlorophenol of any origin which contain about 8 parts by weight of 2,5-dichlorophenol and about 2 parts by weight of 2,4-dichlorophenol can be used for the process according to the invention.
  • Such mixtures are obtained, for example, according to US Pat. No. 2,799,714 in large amounts when reacting 1,2,4-trichlorobenzene with sodium hydroxide solution in the presence of methanol in an autoclave at elevated temperatures and pressures.
  • the process according to the invention is carried out in at least two crystallization stages.
  • the 2,5- / 2,4-dichlorophenol mixture which is expediently liquefied by melting, is thoroughly mixed, for example, with 0.15 to 0.5 part by weight of water, the addition of 0.2 part by weight of water being particularly preferred in order to achieve a good cleaning effect is. Care must be taken during mixing that the organic phase does not solidify prematurely, which can expediently be achieved by maintaining a temperature of 50 to 70 ° C.
  • the mixture is then cooled, preferably to 5 to 25 ° C, depending on the desired degree of purity, the prepurified 2,5-dichlorophenol crystallizing out, while most of the 2,4-dichlorophenol remains in the mother liquor.
  • the crystals thus obtained are separated off by customary methods, for example by filtration, decanting, centrifuging or the like, and it may be expedient to keep the mixture in a stirrable state by adding water to facilitate the separation.
  • the crystals obtained in this way are transferred to a second cleaning stage either immediately or advantageously after one or more washes with cold water.
  • the crystal mass is melted and mixed again with 1.5 to 3 parts by weight of hot water, the use of 2 parts by weight of water having proven particularly advantageous for achieving a particularly good cleaning effect. It is then cooled, depending on the desired degree of purity, preferably to 20 to 35 ° C, whereupon crystallization occurs.
  • the crystals are separated off by one of the methods indicated above and expediently washed once or more times with water. In this way, largely pure 2,5-dichlorophenol with a purity of 95 to 99% is obtained. In most cases, these products are already sufficiently pure for further use. In cases in which products with a particularly high degree of purity are desired, the crystallization step described last can be repeated one or more times.
  • the method according to the invention is particularly environmentally friendly.
  • the water used is circulated after the organic phase introduced during the process has been separated off.
  • the wastewater problem can be solved in a particularly simple and environmentally friendly manner.
  • the organic phases of the second and, if appropriate, further crystallization stages are returned to the first crystallization stage for renewed purification, as a result of which the yield can be significantly improved.
  • the dichlorophenol mixture is distilled over a column in a water jet vacuum.
  • the fraction (257g) which transitions at 89 to 91 ° C / 12mm contains: 82.6% 2,5-dichlorophenol, 16.9% 2,4-dichlorophenol and 0.5% 3,4-dichlorophenol.
  • 255ml (330g) 2,5- / 2,4-dichlorophenol mixture are mixed with 65ml water at 60 ° C and cooled to 20 ° C with stirring. After crystallization has started and the temperature has risen, 200 ml of cold water are added for dilution. The mixture is cooled further to 15 ° C, the crystals are suctioned off and washed twice with 500 ml of cold water. The mother liquor and the washing filtrates are combined and separated in the heat in a separating funnel. The water is reused, the organic phase is discarded or can be used for other reactions.
  • 200ml (255g) of melted filter cake from the 1st stage are mixed with 400ml of water at 70oC and cooled to 30oC with stirring. After crystallization has started and the temperature has risen, cooling is continued to 30 ° C. The crystals are suctioned off and washed with 150 ml of cold water. The mother liquor and the washing filtrate are combined and separated in the heat in a separating funnel. The water is reused, the organic phase becomes the feed product of the 1st S tu fe fed.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

Un procédé permet de produire du 2,5-dichlorphénol ayant une teneur comprise entre 95% et 99%. Un mélange de 2,5-dichlorphénol et de 2,4-dichlorphénol est recristallisé plusieurs fois en présence de l'eau. L'eau résultant de la séparation des substances solides est remise en circulation et la phase organique séparée du filtrat lors de la deuxième étape et des étapes suivantes est rajoutée au produit de base.
EP19860902391 1985-04-11 1986-04-01 Procede de production de 2,5-dichlorphenol Withdrawn EP0217897A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3512877 1985-04-11
DE19853512877 DE3512877C1 (de) 1985-04-11 1985-04-11 Verfahren zur Gewinnung von 2,5-Dichlorphenol aus einem Isomerengemisch mit 2,4-Dichlorphenol

Publications (1)

Publication Number Publication Date
EP0217897A1 true EP0217897A1 (fr) 1987-04-15

Family

ID=6267649

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860902391 Withdrawn EP0217897A1 (fr) 1985-04-11 1986-04-01 Procede de production de 2,5-dichlorphenol

Country Status (3)

Country Link
EP (1) EP0217897A1 (fr)
DE (1) DE3512877C1 (fr)
WO (1) WO1986006062A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4861919A (en) * 1988-02-29 1989-08-29 The Dow Chemical Company Countercurrent multi-stage water crystallization of aromatic compounds
DK3052462T3 (en) 2013-10-04 2018-12-17 Basf Se SELECTIVE HYDROLYSIS AND ALCOHOLYSIS OF CHLORED BENZENES
EA201600429A1 (ru) * 2013-12-04 2016-11-30 Басф Се Способ очистки 2,5-дихлорфенола
US10087133B2 (en) 2013-12-11 2018-10-02 Basf Se Process for providing dihalogen substituted salicylic acid derivatives
AR100506A1 (es) 2014-05-19 2016-10-12 Basf Se Proceso de obtención del herbicida dicamba

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2708209A (en) * 1953-10-29 1955-05-10 Olin Mathieson Process for selective crystallization of 2, 5-dichlorophenol

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8606062A1 *

Also Published As

Publication number Publication date
DE3512877C1 (de) 1986-11-27
WO1986006062A1 (fr) 1986-10-23

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Legal Events

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Effective date: 19890510