DE1027680B - Process for the preparation of 2-methyl-4-chlorophenoxyacetic acid and its salts - Google Patents
Process for the preparation of 2-methyl-4-chlorophenoxyacetic acid and its saltsInfo
- Publication number
- DE1027680B DE1027680B DESCH18341A DESC018341A DE1027680B DE 1027680 B DE1027680 B DE 1027680B DE SCH18341 A DESCH18341 A DE SCH18341A DE SC018341 A DESC018341 A DE SC018341A DE 1027680 B DE1027680 B DE 1027680B
- Authority
- DE
- Germany
- Prior art keywords
- acid
- methyl
- salts
- preparation
- hypochlorite
- 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
- WHKUVVPPKQRRBV-UHFFFAOYSA-N Trasan Chemical compound CC1=CC(Cl)=CC=C1OCC(O)=O WHKUVVPPKQRRBV-UHFFFAOYSA-N 0.000 title claims description 8
- 239000005574 MCPA Substances 0.000 title claims description 7
- 238000000034 method Methods 0.000 title claims description 6
- 238000002360 preparation method Methods 0.000 title claims description 4
- 150000003839 salts Chemical class 0.000 title claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 16
- 239000002253 acid Substances 0.000 claims description 11
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 claims description 11
- QJVXBRUGKLCUMY-UHFFFAOYSA-N 2-(2-methylphenoxy)acetic acid Chemical compound CC1=CC=CC=C1OCC(O)=O QJVXBRUGKLCUMY-UHFFFAOYSA-N 0.000 claims description 5
- 238000005660 chlorination reaction Methods 0.000 claims description 4
- -1 alkali metal salts Chemical class 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 239000003513 alkali Substances 0.000 claims description 2
- 229910052783 alkali metal Inorganic materials 0.000 claims description 2
- 150000007513 acids Chemical class 0.000 claims 2
- 239000002244 precipitate Substances 0.000 claims 1
- 239000000243 solution Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 4
- 241000196324 Embryophyta Species 0.000 description 3
- 239000005708 Sodium hypochlorite Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 3
- 159000000000 sodium salts Chemical class 0.000 description 3
- QTWJRLJHJPIABL-UHFFFAOYSA-N 2-methylphenol;3-methylphenol;4-methylphenol Chemical compound CC1=CC=C(O)C=C1.CC1=CC=CC(O)=C1.CC1=CC=CC=C1O QTWJRLJHJPIABL-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229930003836 cresol Natural products 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 235000013339 cereals Nutrition 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C59/00—Compounds having carboxyl groups bound to acyclic carbon atoms and containing any of the groups OH, O—metal, —CHO, keto, ether, groups, groups, or groups
- C07C59/40—Unsaturated compounds
- C07C59/58—Unsaturated compounds containing ether groups, groups, groups, or groups
- C07C59/64—Unsaturated compounds containing ether groups, groups, groups, or groups containing six-membered aromatic rings
- C07C59/66—Unsaturated compounds containing ether groups, groups, groups, or groups containing six-membered aromatic rings the non-carboxylic part of the ether containing six-membered aromatic rings
- C07C59/68—Unsaturated compounds containing ether groups, groups, groups, or groups containing six-membered aromatic rings the non-carboxylic part of the ether containing six-membered aromatic rings the oxygen atom of the ether group being bound to a non-condensed six-membered aromatic ring
- C07C59/70—Ethers of hydroxy-acetic acid, e.g. substitutes on the ring
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
Verfahren zur Herstellung von 2-Methyl-4-chlorphenoxyessigsäure und ihren Salzen Es ist bekannt, daß die 2-Methyl-4-chlorphenoxyessigsäure bzw. ihre Salze ausgezeichnete Mittel zur Bekämpfung von Unkräutern im Getreide und auf Grönland darstellen. Insbesondere haben Präparate. die diese Stoffe enthalten, eine besonders zuverlässige und nachhaltige Wirkung auch gegen zahlreiche bis her schwer hekämpfbare Wurzelunkräuter, wobei die Wirkung auf Kulturpflanzen besonders milde und schonend ist. Man hat bisher die 2-Methvl-4-chlorphenoxyessigsäure dadurch erhalten, daß man von der chlorfreien Verhindung ausging und diese mit molekularem Chlor hehandelte, wobei Substitution in para-Stellung stattfindet. Das Arbeiten mit gasförmigem Chlor ist an sich betriebsmäßig wenig erwünscht. Process for the preparation of 2-methyl-4-chlorophenoxyacetic acid and Its salts It is known that 2-methyl-4-chlorophenoxyacetic acid or its Salts are an excellent means of combating weeds in cereals and on Greenland represent. In particular, have preparations. that contain these substances, one in particular reliable and lasting effect even against numerous previously difficult to fight Root weeds, with the effect on cultivated plants being particularly mild and gentle is. So far, 2-Methvl-4-chlorophenoxyacetic acid has been obtained in that one started from the chlorine-free prevention and treated this with molecular chlorine, substitution takes place in the para position. Working with gaseous chlorine is not very desirable in terms of operation.
Man hat daher versucht, die Chlorierung in anderer Weise vorzunehmen. Hierzu bediente man sich des Alkalihypochlorits und verfuhr in der Weise, daß man die unchlorierte Säure in Alkali löste, zu dieser Lösung das Hypochlorit hinzufügte und dann gegehenenfalls die Säure durch Hinzufügen von Salzsäure in Freiheit setzte. Es zeigte sich jedoch, daß auch dieses Verfahren Nachteile besaß. denn normalerweise waren die zur Anwendung kommenden Mengen des llypoclllorits un verhältnismäß ig hoch (200 bis 300 0/o der Theorie). zum anderen waren aher auch die Ausbeuteln wenig befriedigend (70 bis 80°/o), und die Reinheit der so erhaltenen Verbindungen ließ zu wünschen übrig. Attempts have therefore been made to carry out the chlorination in a different way. For this purpose one used the alkali metal hypochlorite and proceeded in such a way that one dissolved the unchlorinated acid in alkali, added the hypochlorite to this solution and then, if necessary, set the acid free by adding hydrochloric acid. It was found, however, that this method also had disadvantages. because usually the amounts of glyphocyl chloride used were disproportionate high (200 to 300 per cent of theory). on the other hand, the exploitation was also little satisfactory (70 to 80%), and the purity of the compounds thus obtained was to be desired.
Es wurde IIUII gefunden. daß man überraschenderweise die Chlorierung auch durchführen kann, wenn man in einem sauren Milieu arbeitet. Man verfährt dabei zweckmäßig in der Weise, daß man von einer wäßrigen Lösung des Natriumsalzes der 2-Methylphenoxyessigsäure ausgeht. Aus dieser Lösung fällt man mittels einer Säure, wie z. B. Salzsäure, die freie Säure aus, vorteilhaft bei einem PH von 1, und fügt zu der so erhaltenen feinen Suspension bei Temperaturen bis höchstens 200 C die benötigte Hypochloritmenge hinzu, zweckmäßig in geringem Überschuß (110%) und vorteilhaft portionsweise. Es setzt dann die Chlorierung ein, wobei ein Teil der gebildetell chlorierten Verbindung durch das in der Hypochloritlösung vorhandene freie Alkalihydroxyd in Lösung geht. Will man die freie 2-Methyl-4-chlorpllerloxyessigsäure erhalten, so ist es erforderlich. daß man das Reaktionsgemisch ansäuert, zum Beispiel mit Salzsäure. Man erhält diese Verbinduiig in ausgezeichneter Ausbeute und in einem hervorragenden Reinheitsgrad. IIUII was found. that, surprisingly, the chlorination can also be carried out when working in an acidic environment. One proceeds thereby expediently in such a way that one of an aqueous solution of the sodium salt of 2-methylphenoxyacetic acid goes out. From this solution one falls by means of an acid, such as B. hydrochloric acid, the free acid from, advantageous at a pH of 1, and adds to the fine suspension thus obtained at temperatures up to a maximum of 200 C die Add the required amount of hypochlorite, expediently in a slight excess (110%) and advantageous in portions. Chlorination then sets in, some of which is formed chlorinated compound by the free alkali hydroxide present in the hypochlorite solution goes into solution. If you want to get the free 2-methyl-4-chloropllerloxyacetic acid, so it is required. that the reaction mixture is acidified, for example with Hydrochloric acid. This compound is obtained in excellent yield and in one excellent degree of purity.
Beispiel 1 151 kg 2-fethylphenoxyessigsäure werden al Natriumsalz in einer Konzentration von 61/20/0 der Säure in Wasser (etwa 23301) gelöst. Dann wird mit 125 1 300/oiger Salzsäure unter gutem Rühren und Kühlen auf 12 bis 130 C bis auf PH 1 angesäuert. Nun werden innerhalb 75 Minuten 75,8 kg Natriumhypochlorit (112°/o der Theorie) als 170/oige wäßrige Lösung unter dauerndem Kühlen und kräftigem Rühren zugesetzt. I)ie Temperatur steigt dabei auf etwa 200 C. Das End-pH beträgt 4 bis 4,8. Darnach wird die 2-Metbyl-4-chlorphenoxyessigsäure mit 45 1 300/oiger Salzsäure ausgefällt. Example 1 151 kg of 2-methylphenoxyacetic acid are used as the sodium salt dissolved at a concentration of 61/20/0 of the acid in water (approx. 23301). then will with 125 1,300% hydrochloric acid with thorough stirring and cooling to 12 to 130 ° C acidified to PH 1. 75.8 kg of sodium hypochlorite are now obtained within 75 minutes (112% of theory) as a 170% aqueous solution with constant cooling and vigorous Stir added. I) The temperature rises to about 200 C. The final pH is 4 to 4.8. The 2-methyl-4-chlorophenoxyacetic acid is then converted to 45 1,300 per cent Hydrochloric acid precipitated.
Die Ausbeute an dieser Säure beträgt nach dem Waschen und Trocknen 162,5 kg (89,20/a der Theorie). Das Molgewicht beträgt 201, der Schmelzpunkt liegt zwischen 115 und 1160 C. beispiel 2 120 kg 2-Methylphenoxyessigsäure als Natriumsalz, die noch von ihrer Herstellung mit geringen Mengen von Kresol verunreinigt ist, werden in einer Konzentration von 62/20/0 der Säure in Wasser (etwa 1845 1) gelöst und nun mit 4,5 kg (8,40/0 der Theorie) Natriumhypochlorit versetzt. Diese Menge entspricht etwa der des vorhandenen Kresols. Nach einer Rührzeit voil etwa 15 Minuten wird unter Rühren und Kühlen mit 140 1 300/oiger Salzsäure bis auf ein PH 1 angesäuert. Nun werden unter Kühlen und kräftigem Rühren 55,7 kg Natriumhypochlorit (103,60/o der Theorie) als wäßrige 170/oige Lösung innerhalb von 50 Alinuten zugesetzt. Das End-pn beträgt 4,2. Sodann wird mit 65 1 300/oiger Salzsäure die gebildete 2-Methyl-4-chlorphenoxyessigsäure ausgefällt. Die Ausbeute beträgt 126,1 kg (87°/o der Theorie). Das Molgewicht beträgt 202, der Schmelzpunkt 116 bis 1170 C. The yield of this acid is after washing and drying 162.5 kg (89.20 / a of theory). The molecular weight is 201, the melting point is between 115 and 1160 C. Example 2 120 kg of 2-methylphenoxyacetic acid as sodium salt, which is still contaminated with small amounts of cresol from its production, are dissolved in water (approx. 1845 l) in a concentration of 62/20/0 of the acid and now 4.5 kg (8.40 / 0 of theory) sodium hypochlorite are added. This quantity corresponds roughly to that of the existing cresol. After stirring for about 15 minutes is acidified to pH 1 with 140 1,300% hydrochloric acid while stirring and cooling. 55.7 kg of sodium hypochlorite (103.60 / o theory) added as an aqueous 170% solution within 50 minutes. That End-pn is 4.2. Then the 2-methyl-4-chlorophenoxyacetic acid formed is mixed with 65 1,300% hydrochloric acid failed. The yield is 126.1 kg (87% of theory). The molecular weight is 202, the melting point 116 to 1170 C.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DESCH18341A DE1027680B (en) | 1955-07-13 | 1955-07-13 | Process for the preparation of 2-methyl-4-chlorophenoxyacetic acid and its salts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DESCH18341A DE1027680B (en) | 1955-07-13 | 1955-07-13 | Process for the preparation of 2-methyl-4-chlorophenoxyacetic acid and its salts |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE1027680B true DE1027680B (en) | 1958-04-10 |
Family
ID=7428192
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DESCH18341A Pending DE1027680B (en) | 1955-07-13 | 1955-07-13 | Process for the preparation of 2-methyl-4-chlorophenoxyacetic acid and its salts |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE1027680B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0055357A1 (en) * | 1980-12-31 | 1982-07-07 | BASF Aktiengesellschaft | Process for the preparation of chlorinated phenoxyalkanoic acids |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB698022A (en) * | 1951-07-05 | 1953-10-07 | Dow Chemical Co | Process for the purification of phenoxy-aliphatic-mono-carboxylic acids |
-
1955
- 1955-07-13 DE DESCH18341A patent/DE1027680B/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB698022A (en) * | 1951-07-05 | 1953-10-07 | Dow Chemical Co | Process for the purification of phenoxy-aliphatic-mono-carboxylic acids |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0055357A1 (en) * | 1980-12-31 | 1982-07-07 | BASF Aktiengesellschaft | Process for the preparation of chlorinated phenoxyalkanoic acids |
| US4515985A (en) * | 1980-12-31 | 1985-05-07 | Basf Aktiengesellschaft | Preparation of chlorinated phenoxyalkanoic acids |
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