Polymers and synthesis Flashcards
What is a zwitterion?
At a certain, specific pH, an alpha- amino acid will exist with NH3+ and COO-. Positive and negative charge cancels out.
When is a zwitterion formed?
At the isoelectric point (pH value).
Why do amino acids have high melting point?
The + and - charges causes the molecules to attract each other electrostatically- more energy needed to break them apart.
What is an optical isomer?
- Non-superimposible image of it’s self
- 4 different groups around one carbon
- Stereoisomer
What form do optical isomers exist as and what effect does it have?
- They exist in (+) and (-) forms.
- (+) rotates plane polarised light clockwise.
- (-) rotates plane polarised light anti-clockwise.
What are the two types of polymers?
Polyesters and polyamides
What two type of monomers join together to make a polyester?
diol+ dicarboxylic acid
What type of monomers join together to make a polyester?
Hydroxycarboxylic acids
What two type of monomers join together to make a polyamide?
Diamine+ dicarboxylic acid
What type of monomers join together to make a polyamide?
Amino acids.
What is the general formula of an amino acid?
RCH(NH2)COOH
What do different R groups do?
May result in different isoelectric points
What reactants are used in the production of Terylene and what type of compound is it?
A polyester
Ethan-1,2-diol and Benzene-1,4-dicarboxylic acid
What reactants are used in the production of poly lactic acid and what type of compound is it?
A polyester
-Lactic acid
What reactants are used in the production of nylon-6,6 and what type of compound is it?
Polyamide
1,6-diaminohexane and hexane-1,6-dicarboxylic acid
What reactants are used in the production of Kevlar and what type of compound is it?
Polyamide
Benzene-1,4-dicarboxylic acid and Benzene-1,4-diamine
What is the difference between condensation and addition reactions?
Addition: - Only 1 type of monomer - Has to contain C=C Condensation: - 1 or 2 types of monomers
What tow ways are there of breaking down condensation polymers?
Base hydrolysis: NaOH/H2O
Acid hydrolysis: H+/H2O
Define biodegradable
Polymer that breaks down completely into CO2 and H2O.
Define degradable polymer
Polymer that breaks down into smaller fragments when exposed to light, heat or moisture.
What is pharmacological activity?
It depends on whether an optical isomer can fit onto the receptor site of a biological molecule (e.g enzymes).
One optical isomer is active, so need to produce one.
Why do optical isomers need to be separated in medicine?
One optical isomer may be active and the presence of the inactive form may decrease activity of active form or be toxic/fatality.
What are two examples of drugs which contained harmful optical isomers?
Post thalidomide and Post Seldane
What are the advantages of having a single isomer?
- Risks from undesirable side effects are reduced.
- Drug doses are reduced- only the active form is present.
