Difference Between Allyl And Vinyl

What Is Allyl?

An allyl in organic chemistry is a substituent functional group with a general molecular formula RCH2CH=CH2. Allyl group holds three carbon atoms and five hydrogen atoms, which gets attached to any other group of atoms through –CH2 group. Allyl group consists of (-CH2-) methylene bridge and is attached with (-CH=CH2) vinyl group. It contains SP3 hybridized allyl carbon atom, which is adjacent to sp2 hybridized carbon atom.

The allylic carbon atom is more reactive than normal alkanes and it can easily form a stable carbocation because it is adjacent to the vinyl carbon that can delocalize electrons to stabilize the positive charge.

Due to the stability of the carbocation, allyl compounds radially form intermediates during the reaction, for example, the SN1 reaction.

Allylic compounds are precursors to many natural products including natural rubber and biosynthesis of terpenes. Other allylic compounds such as allyl chloride is used to produce plastics and used as an alkylating agent. 

What You Need To Know About Allyl

  • The general molecular formula is RCH2CH=CH2 .
  • The allyl group is attached to the rest of the molecule through –CH2– group.
  • Allyl group holds three carbon atoms and five hydrogen atoms.
  • Allylic carbon atom can form stable carbocations due to electron delocalization.
  • Allyl contains SP3 hybridized allyl carbon atom, which is adjacent to sp2 hybridized carbon atom.
  • Allylic compounds are precursors to many natural products including natural rubber and biosynthesis of terpenes. Other allylic compounds such as allyl chloride is used to produce plastics and used as an alkylating agent.  

What Is Vinyl?

Vinyl or ethenyl is the functional group with formula –CH=CH2. It is the ethylene molecule less one hydrogen atom. The name is also used for any compound containing that group, namely R-CH=CH2 where R is any other group of atoms.

Vinyl compounds contain the hydrocarbon vinyl group (CH2=CH-). The molecule of a single vinyl compound can be made to polymerize; that is, to join end to end, forming a polyvinyl compound such as polyvinyl chloride (PVC), Polyvinyl acetate (PVA) or polyvinyl fluoride (PVF). The molecules of two different compounds can also be made to link up, forming a copolymer, such as the  plastic Vinylite and the textile fibre vinyon.

Vinyl compound and its derivatives are useful in making plastic film, sheeting, upholstery, floor tile, inflatable and solid toys, buttons,  molded and extruded articles, fibres for weaving into fabric; insulation for wire; screening; tubing especially for chemicals; substitutes for rubber and components of water-base paints and textile finishes.

What You Need To Know About Vinyl

  • The general molecular formula is RCH=CH2.
  • The vinyl group is directly attached to the rest of the molecule.
  • Vinyl group has two carbon atoms and three hydrogen atoms.
  • Vinylic carbocations are very unstable due to lack of P-character.
  • Vinyl contains sp2 hybridized carbon atoms.
  • Most of vinyl derivatives are used in polymer industry. Examples are Vinyl Chloride, Vinyl Fluoride, Vinyl Acetate, Vinylidene and Vinylene. Vinyl has many other uses because of its ability to be combined with various additives and modifiers.

Difference Between Allyl And Vinyl In Tabular Form

BASIS OF COMPARISON ALLYL VINYL
Molecular Formula The general molecular formula is RCH2CH=CH2 .   The general molecular formula is RCH=CH2.  
Group Attachment The allyl group is attached to the rest of the molecule through –CH2– group.   The vinyl group is directly attached to the rest of the molecule.  
Number Of Carbon And Hydrogen Atoms Allyl group holds three carbon atoms and five hydrogen atoms.   Vinyl group has two carbon atoms and three hydrogen atoms.  
Carbocations Allylic carbon atom can form stable carbocations due to electron delocalization.   Vinylic carbocations are very unstable due to lack of P-character.  
SP Hybridized Carbon Atoms Allyl contains SP3 hybridized allyl carbon atom, which is adjacent to sp2 hybridized carbon atom.   Vinyl contains sp2 hybridized carbon atoms.  
Application Allylic compounds are precursors to many natural products including natural rubber and biosynthesis of terpenes. Most of vinyl derivatives are used in polymer industry.