2-chloroethylphosphonic acid

Structural formula
General
Surname	2-chloroethylphosphonic acid
other names	Ethephon; Ethrel;
Molecular formula	C 2 H 6 ClO 3 P
Brief description	hygroscopic solid
External identifiers / databases
EC number	240-718-3
ECHA InfoCard	100.037.002
PubChem	27982
Wikidata	Q209355
properties
Molar mass	144.49 g mol −1
Physical state	firmly
Melting point	74–75 ° C (decomposition)
solubility	easy in water: 1239 g l −1 ; Easily soluble in polar organic solvents such as methanol, ethanol, isopropanol and acetone;
safety instructions
H and P phrases	H: 302 + 332-311-314-411
	EUH: 071
	P: 261-273-280-303 + 361 + 353-304 + 340-310-305 + 351 + 338
Toxicological data	1560 mg kg −1 ( LD 50 , rat , oral )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

2-Chloroethylphosphonic acid is a chemical compound known under the name Ethephon from the group of organic chlorine compounds and phosphonic acid derivatives , which is effective as an ethylene developer.

Extraction and presentation

2-Chloroethylphosphonic acid can be obtained from phosphorus trichloride with ethylene oxide , which react to form tris-2-chloroethylphosphite. This is converted to bis-2-chloroethyl-2-chlorophosphonate and this is then further converted to ethephon with hydrogen chloride .

properties

2-chloroethylphosphonic acid is a flammable, hygroscopic solid that is easily soluble in water. It decomposes at temperatures above 74–75 ° C. Its aqueous solution is acidic.

use

Estimated US application rate in 2011

2-chloroethylphosphonic acid is used as an active ingredient in plant protection products. It is a plant growth regulator with systemic properties. The effect is based on the release of ethylene , which is absorbed by the plants and intervenes in growth processes. Either the maturation process of z. B. pineapple, apple, paprika or tomato accelerated, induction of flower formation or it acts as a growth inhibitor for barley and rye, whereby the upper internodes are shortened.

In the USA, Ethephon is used on a large scale (more than 4,500 tons per year) to open the cotton bolls ( English boll opening ).

Use in fruit growing
purpose	Type of fruit	concentration	Application time
Flower formation	Apple	150-250 ppm	4 weeks after flowering
Chemical thinning	Apple, plum	150-500 ppm	Flowering until 6 weeks later
Promotion of fruit ripeness and color	Apple	250 ppm	2 weeks before harvest
Easier harvest (better detachment of the fruit)	Cherry, plum, currant, bilberry, lingonberry	250-500 ppm	10 days before harvest
Easier harvest (better loosening of the nut from the fruit shell)	walnut	500 ppm	at the beginning of bursting of the pods

Admission

The active ingredient was included in Annex I of Directive 91/414 / EEC with Directive 2006/85 / EC of the EU Commission of October 23, 2006. In January 2011, Spanish peppers were recalled in German supermarkets due to Ethephon contamination well above the limit values. In Switzerland, there is a relatively high maximum residue level for blueberries of 5 milligrams ethephon per kilogram.

safety instructions

The vapors of 2-chloroethylphosphonic acid can form an explosive mixture with air.

Trade names

2-Chloroethylphosphonic acid is sold under the trade names Arvest, Bromeflor, Etheverse, Flordimex, Flordimex T-Extra, Cerone, Etherel, Chipco Florel Pro and Prep.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on 2-chloroethylphosphonic acid in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ ^a ^b Entry Etephon at Extoxnet.
↑ Entry on 2-chloroethylphosphonic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ ^a ^b Federal Institute for Risk Assessment: Health Assessment of Ethephon Residues in Paprika (PDF; 51 kB).
↑ Thomas A. Unger: Pesticide Synthesis Handbook . Noyes Publications, Park Ridge, NJ 1996, ISBN 0-8155-1401-8 , pp. 271 ( limited preview in Google Book search).
↑ Bill Weir, JM Gaggero: Ethephon may hasten cotton boll opening, increase yield . In: California Agriculture . September / October, 1982, p. 28-29 ( ucanr.edu [PDF]).
↑ Lucas' instructions for fruit growing. 31st edition 1992, p. 206.
↑ Information in active substance
↑ Ordinance of the EDI on the maximum levels for pesticide residues in or on products of plant and animal origin. In: admin.ch . Retrieved February 6, 2020 .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on 2-chloroethylphosphonic acid in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[extoxnet-2] Entry Etephon at Extoxnet.

[CLP_100.037.002-3] Entry on 2-chloroethylphosphonic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[bfr-4] Federal Institute for Risk Assessment: Health Assessment of Ethephon Residues in Paprika (PDF; 51 kB).

[unger-5] Thomas A. Unger: Pesticide Synthesis Handbook . Noyes Publications, Park Ridge, NJ 1996, ISBN 0-8155-1401-8 , pp. 271 ( limited preview in Google Book search).

[6] Bill Weir, JM Gaggero: Ethephon may hasten cotton boll opening, increase yield . In: California Agriculture . September / October, 1982, p. 28-29 ( ucanr.edu [PDF]).

[7] Lucas' instructions for fruit growing. 31st edition 1992, p. 206.

[8] Information in active substance

[9] Ordinance of the EDI on the maximum levels for pesticide residues in or on products of plant and animal origin. In: admin.ch . Retrieved February 6, 2020 .