Week 12 Flashcards
When carboxylic acids are put in water…
OH group readily deprotonates to give a carboxylate line plus protons
Carboxylic acids react with strong bases
They participate in acid-base reactions, which can go to completion.
Zwitterion
Distinctive charges within it but the overall net charge is zero
Isoelectric point
the point at which the pH of the amino acid is zwitterion in solution
Fatty acids
long chain carboxylic acids (ranges from C8 – C20)
Saturated fatty acids
have alkane chain (e.g. coconut oil, animal fats, butter)
Monounsaturated fatty acids
contain one double bond (e.g. olive, canola, sesame oils)
Polyunsaturated fatty acids
contain two or more double bonds (e.g. sunflower, soybean oils)
When you esterify long chain fatty acids you end up with…
Fats (solid) and oils (liquid) are esters of fatty acids and an alcohol
It is possible to make an ester by reacting a carboxylic acid and an alcohol directly
True, But needs a catalyst (H+) and sometimes heat.
Water is liberated
Making amides by reacting carboxylic acids directly with amines generally works
False, because amine groups are quite basic, protonation occurs and you end up with a salt
Fatty acid components (saturated)
palmitic acid
stearic acid
arachidic acid
Fatty acid components (unsaturated)
palmitoleic acid
aleic acid
Saturated fats and unsaturated fats with an E double bond
pack well together and tend to be solids at room temp
unsaturated fats with a Z double bond
pack less well and are liquid at room temp
Soap
Key ingredients:
* sodium salts of long chain fatty acids.
The combination of a hydrophobic hydrocarbon chain and polar hydrophilic carboxylate group pulls grease into water.
how soap cleans
- When molecules are put in water, they aggregate together to form micelles
- Water is excluded from the centre of the structure
- Water interacts strongly with the carboxylate groups
- Fatty dirt particles gets trapped within the centre of micelle (hydrophobic) which is easily washed away
how soap is made
heating fats with concentrated sodium hydroxide (NaOH).
Synthetic detergents
Does not contain a carboxyl group
* Instead uses a polar group such as sulphate
* Cheaper to make and have stronger grease penetrating power
soap vs. covid
breaking up the lipid bilayer and and virus components removed in micelle
The chemistry of alcohols is dominated by
the electronegativity of O
* Attached C and H are electron-deficient as a result of being bonded to O
OH group
polar and engages in hydrogen bonding
An alcohol does not readily accept H+
- Equilibrium lies to the left
- It takes a very strong base to remove the H
Phenols
lower pKa values than alcohol, therefore much more acidic
* when placed in water - deprotonation of the OH group occurs to form a hydronium ion
Conjugation
3 or more p-orbitals in an uninterrupted sequence can share electrons like an electric circuit
Aromaticity requires three things:
- Aromatic systems are conjugated, but also
- Conjugated system is cyclic, and
- Conjugated system contains 4n+2 𝛑 electrons
Amines
Amines contain ≥ 1 organic group(s) bonded to nitrogen
* general formulae RNH2, R2NH, R3N
* are BASIC
Amines can form hydrogen bonds
Nitrogen: 1s2 2s2 2p3
* 3 covalent bonds, leaving a lone pair
* sp3 hybridised, with a lone pair in one orbital
* Good at H-bonding
Carboxylic acids can be converted to acyl chlorides (or acid chlorides) with
a specific chlorinating reagent, thionyl chloride (SOCl2)
Acyl chlorides
very reactive and easily transformed into a range of other things,
* e.g. esters and amides
Acyl chlorides react with ____ to make esters
Alcohols
Acyl chlorides react with ____ to make amides
Amines
Making esters from carboxylic acids
slower reaction, needs a catalyst (H+) and sometimes heat
Amides are important components of many pharmaceuticals, including
Lidocaine, Penicillin, Paracetamol, Prilocaine
acetyl coenzyme A
molecular crane for the delivery of acetate and other groups in biosynthetic processes
Hydrolysis
chemical reaction in which a molecule of water breaks one or more chemical bonds
Oxidation
Oxidation of organic molecules increases their O content or decreases their H content
Oxidation in biology
Oxidation of a molecule makes it more soluble and easier to excrete from the body
Reduction of carboxylic acids
carried out using a strong reducing agent, such as lithium aluminum hydride (LiAlH 4).
* NaBH4 is usually used as it is cheaper and easier to handle
* LiAlH4 is more reactive
