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The difluoromethylene (CF2) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF2 groups
- Source :
- Beilstein Journal of Organic Chemistry, Beilstein Journal of Organic Chemistry, Vol 10, Iss 1, Pp 18-25 (2014)
- Publication Year :
- 2014
- Publisher :
- Beilstein-Institut, 2014.
-
Abstract
- The syntheses of palmitic acids and a nonadecane are reported with CF2 groups located 1,3 or 1,4 to each other along the aliphatic chain. Specifically 8,8,10,10- and 8,8,11,11-tetrafluorohexadecanoic acids (6b and 6c) are prepared as well as the singly modified analogue 8,8-difluorohexadecanoic acid (6a). Also 8,8,11,11-tetrafluorononadecane (27) is prepared as a pure hydrocarbon containing a 1,4-di-CF2 motif. The modified palmitic acids are characterized by differential scanning calorimetry (DSC) to determine melting points and phase behaviour relative to palmitic acid (62.5 °C). It emerges that 6c, with the CF2 groups placed 1,4- to each other, has a significantly higher melting point (89.9 °C) when compared to the other analogues and palmitic acid itself. It is a crystalline compound and the structure reveals an extended anti-zig-zag chain. Similarly 8,8,11,11-tetrafluorononadecane (27) adopts an extended anti-zig-zag structure. This is rationalized by dipolar relaxation between the two CF2 groups placed 1,4 to each other in the extended anti-zig-zag chain and suggests a design modification for long chain aliphatics which can introduce conformational stability.
- Subjects :
- organo-fluorine
Nonadecane
Stereochemistry
difluoromethylene
Organic-compounds
fatty acids
Full Research Paper
lcsh:QD241-441
Palmitic acid
chemistry.chemical_compound
Differential scanning calorimetry
Organo-fluorine
lcsh:Organic chemistry
Fluorination
Phase (matter)
palmitic acid
QD
Fatty acids
lcsh:Science
chemistry.chemical_classification
Organic fluorine chemistry
Reagents
Organofluorine chemistry
Organic Chemistry
C-F Bbond
Difluoromethylene
organic fluorine chemistry
QD Chemistry
fluorination
Crystallography
Chemistry
Hydrocarbon
chemistry
Reagent
Melting point
Flourine
lcsh:Q
Derivatives
Subjects
Details
- Language :
- English
- ISSN :
- 18605397
- Volume :
- 10
- Database :
- OpenAIRE
- Journal :
- Beilstein Journal of Organic Chemistry
- Accession number :
- edsair.doi.dedup.....0d9b4ec4fcf87d0ac25251c3c8b5c436