Disclosed are a pyrazole compound or a salt thereof, a preparation method therefor, a herbicidal composition and use thereof. The pyrazole compound or a salt thereof has a structure as shown in formula (I): ##STR00001##
wherein, R represents ##STR00002##
wherein, R′, R″, and R′″ represent hydrogen, C1-C4 alkyl, C1-C4 halogenated alkyl, C1-C4 alkoxy or halogen, R′, R″, and R′″ may be the same or different; R.sub.1 represents C1-C3 alkyl; R.sub.2 represents hydrogen or C1-C4 alkyl; R.sub.3 represents hydrogen or C1-C6 alkyl, optionally substituted phenyl, optionally substituted pyridyl, optionally substituted alkenyl, optionally substituted alkynyl, C1-C6 alkyl carbonyl, C1-C6 alkoxyl carbonyl, C1-C6 alkyl carbonyl methyl, etc. A compound having a pyrazole structure not only has excellent herbicidal effect on barnyard grass, but also is safe to rice in post-emergence application. More surprisingly, it also has good control efficacy on barnyard grass resistant to major herbicides, such as penoxsulam, quinclorac, cyhalofop-butyl, propanil, etc.

Disclosed are a pyrazole compound or a salt thereof, a preparation method therefor, a herbicidal composition and use thereof. The pyrazole compound or a salt thereof has a structure as shown in formula (I): ##STR00001##
wherein, R represents ##STR00002##
wherein, R′, R″, and R′″ represent hydrogen, C1-C4 alkyl, C1-C4 halogenated alkyl, C1-C4 alkoxy or halogen, R′, R″, and R′″ may be the same or different; R.sub.1 represents C1-C3 alkyl; R.sub.2 represents hydrogen or C1-C4 alkyl; R.sub.3 represents hydrogen or C1-C6 alkyl, optionally substituted phenyl, optionally substituted pyridyl, optionally substituted alkenyl, optionally substituted alkynyl, C1-C6 alkyl carbonyl, C1-C6 alkoxyl carbonyl, C1-C6 alkyl carbonyl methyl, etc. A compound having a pyrazole structure not only has excellent herbicidal effect on barnyard grass, but also is safe to rice in post-emergence application. More surprisingly, it also has good control efficacy on barnyard grass resistant to major herbicides, such as penoxsulam, quinclorac, cyhalofop-butyl, propanil, etc.

The present invention relates to a novel process for the preparation of 9-dichloromethylene-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-ylamine which process comprises a) reacting cyclopentadiene in the presence of a radical initiator and CXCl.sub.3, wherein X is chloro or bromo, to a compound of formula II ##STR00001## aa) reacting cyclopentadiene with CXCl.sub.3, wherein X is chloro, in the presence of a metal catalyst to a compound of formula II ##STR00002## wherein X is chloro, b) reacting the compound of formula II with a base in the presence of an appropriate solvent to the compound of formula III ##STR00003## c) and converting the compound of formula III in the presence of 1,2-dehydro-6-nitrobenzene to the compound of formula IV ##STR00004## and d) hydrogenating the compound of formula IV in the presence of a metal catalyst.

A hydrofluoroolefin compound is represented by the following general formula (I): where R.sub.F1 is a hydrogen atom or CH.sub.3, and (iii) R.sub.F1 is a linear or branched perfluorinated alkyl group having 1 to 10 carbon atoms and optionally including one or more catenated heteroatoms; and R.sub.F2 is a fluorine atom or a linear or branched perfluorinated alkyl group having 1 to 8 carbon atoms and optionally including one or more catenated heteroatoms; with the proviso that when RF2 is a fluorine atom, then RF1 includes at least 2 carbon atoms; or (iv) R.sub.F 1 and R.sub.F2 are bonded together to form a ring structure having 4 to 8 carbon atoms and optionally including one or more catenated heteroatoms.

##STR00001##

A hydrofluoroolefin compound is represented by the following general formula (I): where R.sub.F1 is a hydrogen atom or CH.sub.3, and (iii) R.sub.F1 is a linear or branched perfluorinated alkyl group having 1 to 10 carbon atoms and optionally including one or more catenated heteroatoms; and R.sub.F2 is a fluorine atom or a linear or branched perfluorinated alkyl group having 1 to 8 carbon atoms and optionally including one or more catenated heteroatoms; with the proviso that when RF2 is a fluorine atom, then RF1 includes at least 2 carbon atoms; or (iv) R.sub.F 1 and R.sub.F2 are bonded together to form a ring structure having 4 to 8 carbon atoms and optionally including one or more catenated heteroatoms.

##STR00001##

A hydrofluoroolefin compound is represented by the following general formula (I): where R.sub.F1 is a hydrogen atom or CH.sub.3, and (iii) R.sub.F1 is a linear or branched perfluorinated alkyl group having 1 to 10 carbon atoms and optionally including one or more catenated heteroatoms; and R.sub.F2 is a fluorine atom or a linear or branched perfluorinated alkyl group having 1 to 8 carbon atoms and optionally including one or more catenated heteroatoms; with the proviso that when RF2 is a fluorine atom, then RF1 includes at least 2 carbon atoms; or (iv) R.sub.F 1 and R.sub.F2 are bonded together to form a ring structure having 4 to 8 carbon atoms and optionally including one or more catenated heteroatoms.

##STR00001##

Provided is a method of manufacturing octafluorocyclopentene by bringing 1-chloroheptafluorocyclopentene into contact with an alkali metal fluoride. The manufacturing method includes a feedstock heating step of heating 1-chloroheptafluorocyclopentene to not lower than 40 C. and not higher than 55 C. and a fluorination step of maintaining a suspension containing a polar aprotic solvent and an alkali metal fluoride at 85 C. or higher while supplying heated 1-chloroheptafluorocyclopentene into the suspension and performing fluorination thereof to obtain octafluorocyclopentene.

Provided is a method of manufacturing octafluorocyclopentene by bringing 1-chloroheptafluorocyclopentene into contact with an alkali metal fluoride. The manufacturing method includes a feedstock heating step of heating 1-chloroheptafluorocyclopentene to not lower than 40 C. and not higher than 55 C. and a fluorination step of maintaining a suspension containing a polar aprotic solvent and an alkali metal fluoride at 85 C. or higher while supplying heated 1-chloroheptafluorocyclopentene into the suspension and performing fluorination thereof to obtain octafluorocyclopentene.

Provided is a method of manufacturing octafluorocyclopentene by bringing 1-chloroheptafluorocyclopentene into contact with an alkali metal fluoride. The manufacturing method includes a feedstock heating step of heating 1-chloroheptafluorocyclopentene to not lower than 40 C. and not higher than 55 C. and a fluorination step of maintaining a suspension containing a polar aprotic solvent and an alkali metal fluoride at 85 C. or higher while supplying heated 1-chloroheptafluorocyclopentene into the suspension and performing fluorination thereof to obtain octafluorocyclopentene.

Provided is a manufacturing method in which 1-chloroheptafluorocyclopentene is brought into contact with an alkali metal fluoride to obtain octafluorocyclopentene. The manufacturing method includes a fluorination step of maintaining, at 85 C. or higher, a suspension containing an alkali metal fluoride suspended in a mixed solvent including a polar aprotic solvent and a glycol ether having a higher boiling point than the polar aprotic solvent while supplying 1-chloroheptafluoropentene into the suspension and performing fluorination thereof to obtain octafluorocyclopentene.