1-Methylcyclopropene

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1-Methylcyclopropene
Skeletal structure of methylcyclopropene
Ball and stick of cyclopropene
Ball and stick of cyclopropene
van der Waals model of cyclopropene
van der Waals model of cyclopropene
Names
Preferred IUPAC name
1-Methylcycloprop-1-ene
Identifiers
3D model (
JSmol
)
Abbreviations 1-MCP
ChEBI
ChemSpider
ECHA InfoCard
100.130.871 Edit this at Wikidata
UNII
  • InChI=1S/C4H6/c1-4-2-3-4/h2H,3H2,1H3 checkY
    Key: SHDPRTQPPWIEJG-UHFFFAOYSA-N checkY
  • InChI=1/C4H6/c1-4-2-3-4/h2H,3H2,1H3
    Key: SHDPRTQPPWIEJG-UHFFFAOYAJ
  • C\1=C(/C)C/1
Properties
C4H6
Molar mass 54.092 g·mol−1
Boiling point 12 °C (54 °F; 285 K)(approx)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

1-Methylcyclopropene (1-MCP) is a

plant growth regulator. It is structurally related to the natural plant hormone ethylene and it is used commercially to slow down the ripening of fruit and to help maintain the freshness of cut flowers.[2]

Synthesis

1-Methylcyclopropene is synthesized by the reaction of methallyl chloride and phenyllithium, which functions as a base:

Phenyl lithium

(base)

 
LiCl + PhH
Rightward reaction arrow with minor product(s) to top right

The phenyllithium should be free of lithium halides. The corresponding reaction of allyl chloride and phenyllithium main affords cyclopropylbenzene.[3]

Isomers

Methylcyclopropene can refer to either of two

isomers, 1-methylcyclopropene covered in this article, or 3-methylcyclopropene[4] which is not covered in this article. 2-methylcyclopropene would be an incorrect name for 1-methylcyclopropene. Also note: methylcyclopropane is yet a different chemical compound, which is a cycloalkane
with the formula C4H8.

Mechanism of action

Commercial use

Two same-aged Abate Fetel pears: unlike the left one, the right one was treated with 1-MCP after the harvest

1-MCP is used commercially to maintain the freshness of ornamental plants and flowers and preventing the ripening of fruits. It is used in enclosed sites, such as coolers, truck trailers, greenhouses, storage facilities, and shipping containers.[9]

Under the brand name EthylBloc, 1-MCP was approved in 1999 by the

U.S. Environmental Protection Agency for use on ornamental crops.[10] For cut flowers, potted flowers, and bedding, nursery and foliage plants, 1-MCP prevents or delays wilting, leaf yellowing, opening, and death.[11][12]

Under the brand name SmartFresh, 1-MCP is used in the agriculture industry by growers, packers, and shippers to prevent or delay the natural ripening process. The use of 1-MCP in agricultural products including apples, kiwifruit, tomatoes, bananas, plums, persimmons, avocados, and melons has been approved and accepted for use in more than 34 countries including the European Union and the United States.[13] Although benefiting from fresher produce and lower cost, the consumer however may be purchasing fruit that is older than expected.[14]

1-MCP is also being developed as a

crop protection technique. By spraying 1-MCP on growing field crops during times of stress, the crops may be protected from moderate heat and drought conditions.[15]

See also

References