Alkanes and radicals 2: Product spread

Alkanes & radicals

Relative stabilities of alkyl radicals

Alkyl groups stabilize carbocations about 5 to 10 times better than when alkyl groups have to stabilize radicals:

Radicals: Resonance >> Hyperconjugation

Carbocations: Hyperconjugation >> Resonance

Hyperconjugation makes the carbocations more stabilized than when hyperconjugation occurs with radicals (not so stable). This is explained due to the fact that in carbocations, both electrons sit in the same binding orbital, with radicals however, one of the electrons is sited in the anti-binding orbital.

Product spread

The product spread (product outcome) is determined by CHANCE and REACTIVITY. The chance (or probability) is based on the relative amount of primary and secundary protons (in the example below 6:4), but secundary hydrogens are more reactive than primary hydrogens, this means both chance and reactivity determine the outcome of the reaction.

Thus to determine the product spread, both chance and intrinsic reactivity have to be considered:

Probabillity: the amount of hydrogens that can be removed to lead to a certain product.
Reactivity: the relative rate with what a hydrogen gets removed.

Some examples of chlorationproducts found below. Radical chlorationreactions are less selective than reactions via a carbocation intermediate.

Comments

Alkynen: Elektrofiele additie

Elektrofiele additie: Waterstofhaliden op alkynen Voorbeeld van waterstofhaliden: HCl, HBr, HF, HI Gebruik van één equivalent waterstofhalide met alkyn (dus 1:1 geen overmaat geen tekort) Bij een overmaat aan het waterstofhalide zal een tweede reactie plaatsvinden op het gehalogeneerde alkyn, ter vorming van een geminaal regioisomeer.

Coca-Cola: Life - myth or truth?

"Coca-Cola Life" Recently the Coca-Cola company released a new beverage: the Coca-Cola Life drink. It should contain less sugar than the normal Coca-Cola drink; a part of the sugar is replaced with the recently approved sweetener from the Stevia plant (stevioglycosides). It's being sold as a 'natural' drink, but those stevioglycosides are as natural as the chemical sweetener aspartame found in Light and Zero drinks. However it is true that the amount of sugar is much lower (being reported as 33%, some say it's around 20%); yet approximately still 3-4 sugar cubes / 33 cl can (5-6 in a normal can). I bought it myself and found that the flavor has not really changed from the original Coca-Cola, however it does taste more "flat" - but definitely true it yourself. The outside of the can has the colour green. I personally do not associate this "healthy - natural" colour with Coca-Cola, but it's growing on me. In sum...

Basic structure of a virus

Very basic explanation of a virus: Virus consists of a - Head - Tail - Legs/Fibres The head contains the DNA/RNA, nucleic acids (genetic material, GM). It depends on what kind of virus we speak of, there are a lot of different kind of viruses. It is protected from the outside with a protein coat, that consists of hemagglutinin and neuraminidases, hence names given for viruses (f.e. H1N1, Influenza virus). The tail connects the head with the legs/fibres. Those legs will make sure the virus can bind on its host, for example a bacterial cell or a human cell. Viruses that bind on bacteria are often called bacteriophages. When connected to a host, the virus will inject its DNA/RNA into the cell via the tail. Once its GM is injected, the virus will normally eject from the cell and fall apart/gets secreted out of the organism. The GM will be implemented into the hosts genome often via reverse transciptases. Now this GM will code for proteins that induce transcription of th...

Pharmacist Blog about what I encounter and find useful/interesting

Search This Blog