Циклопентан: қасиеттері, қолданылуы және қауіпсіздік шаралары

chembox
|Verifiedimages = changed
|Watchedfields = changed
|verifiedrevid = 444653737
|ImageFileL1 Ref =
|ImageFileL1 = Cyclopentane v2. svg
|ImageSizeL1 = 100px
|ImageAltL1 = Skeletal formula
|ImageFileR1 = Cyclopentane3d. png
|ImageSizeR1 = 110px
|ImageAltR1 = Space filling model
|PIN = Cyclopentane
|OtherNames = pentamethylene
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|Section3 = Chembox Hazards
|MainHazards=Flammable
|ExploLimits = 1.1% 8.7%

Cycloalkanes are formed by catalytic reforming. For example, when passed over a hot platinum surface, 2 methylbutane converts into cyclopentane. Cyclopentane has found applications in various industries. As a volatile hydrocarbon, it is an incidental component of some fuels and blowing agents. In recent years, cyclopentane has been used as a refrigerant to replace chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs) as it does not deplete the ozone as much. Cyclopentane requires safety precautions to prevent leakage and ignition when used as a refrigerant as it is both highly flammable and can also cause respiratory arrest when inhaled. Cyclopentane can be fluorinated to give compounds ranging from |C5H9F to perfluorocyclopentane |C5F10. Such species are conceivable refrigerants and specialty solvents. The cyclopentane ring is pervasive in natural products including many useful drugs. Examples include most steroids, prostaglandins, and some lipids.

In a regular pentagon, the angles at the vertices are all 108°, slightly less than the bond angle in perfectly tetrahedrally bonded carbon, which is about 109.47°. However, cyclopentane is not planar in its normal conformations. It puckers in order to increase the distances between the hydrogen atoms (something which does not happen in the planar cyclopentadienyl anion |C5H5 because it doesn't have as many hydrogen atoms). This means that the average C C C angle is less than 108°. There are two conformations that give local minima of the energy, the "envelope" and the "half chair". The envelope has mirror symmetry (C), while the half chair has two fold rotational symmetry (C). In both cases the symmetry implies that there are two pairs of equal C C C angles and one C C C angle that has no pair. In fact for cyclopentane, unlike for cyclohexane (C6H12, see cyclohexane conformation) and higher cycloalkanes, it is not possible geometrically for all the angles and bond lengths to be equal except if it is in the form of a flat regular pentagon.