Chloroethylphosphonic acid

Mepiquat chloride is mixed with 2-chloroethylphosphonic acid to control lodging of winter barley in Europe under the name Terpal. The plants are treated after the first nodes have become visible and treatments may be appHed until the flag leaf develops. Terpal is not used in the United States. 

The phosphonic acid (RP(=0)(0H)2) group is very acidic and will provide solubility for 2-chloroethylphosphonic acid in water. 

The first member of the phosphonate group, 2-chloroethylphosphonic acid, introduced under the trade mark Ethrel , is a plant growth regulator with no herbicidal action. 

In a continuing investigation of sesquiterpenoid stress compounds from Nicotiana species it has been shown that phytuberin (566) and phytuberol (567) are produced on treatment of N. tabacum with the ethylene-releasing substance ethrel (2-chloroethylphosphonic acid). Phytuberol is also generated on inoculation of N. rustica with tobacco mosaic virus (TMV), and solavetivone (568)... 

EINECS/ELINCS 240-718-3 Synonyms Camposan CEPA 2-CEPA Chlorethephon 2-Chlorethylphosphonic acid 2-Chloroethanephosphonic acid 2-Chloroethylphosphonic acid Empirical C2H6CIO3P Formula CICH2CH2PO3H2 Properties Needles insol. in petrol, ether sol. in water, methanol, acetone, ethylene glycol, propylene glycol si. sol. in benzene, toluene pract. insol. in petrol, ether m.w. 144.50 m.p. 74-75 C... 

An unconventional but very convenient method for the synthesis of VPA from the starting material 2-chloroethylphosphonic acid is by a microwave assisted technique. The pyrolysis of technical grade 2-chloroethylphosphonic acid is performed in a reactor inserted in a microwave oven, with the pyrolysis temperature controlled at 220-230 °C. The reaction occurs in high yield within a few minutes instead of the 4-12 hours required by conventional methods. 

Glyphosine, when sprayed on foliage at the correct time, increases the sucrose yield of sugar cane by as much as 10%. Another example is Ethrel (2-chloroethylphosphonic acid) which, when sprayed on fruit plants, releases ethylene directly into the plant tissue. This will accelerate the maturing of many fruits and vegetables, and increase their yield. The use of agrochemicals of this kind may increase considerably, provided that their cost remains competitive with the value of the extra crop obtained. 

As discussed in A Word About... Ethylene on pp. 98-99, 2-chloroethylphosphonic acid, ClCH2CH2PO(OH)2, is a commercially synthesized compound that is used for inducing the ripening of fruit. 

McReynolds RD, Kossuth SV (1984) CEPA (2-chloroethylphosphonic acid) in sulphuric acid paste increases oleoresin yields. Southern J Appl For 8(3) 168-172 Clements RW (1970) Front and back face gum yields from 2,4-D and H2S04 treatments on slash pine. USDA Forest Service Research Note 132, Southeastern Forest Experiment Station, Asheville, North Carolina... 

Suge H (1971 a) 2-Chloroethylphosphonic acid as ethylene releasing agent for the stimulation of rice and the inhibition of wheat, barley, oat and rye coleoptile growth. Proc Crop Sci Soc Jpn 40 127-131... 

Winter barley partienlarly ean be susceptible to lodging. Stiff-strawed varieties should be ehosen. To eontrol lodging in winter barley, chlormequat is not as effective in barley as in wheat products containing 2-chloroethylphosphonic acid or trinexapac-ethyl can be nsed. The later applications will control necking and... 

Ethylene and compounds capable of releasing ethylene under suitable conditions are utihzed commercially for enhancing the ripening process. A number of such compounds are known, e.g., 2-chloroethylphosphonic acid (ethephon R=H or CH2-CH2CI) (Formula 18.46). 

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