organics 2 Flashcards
what is the functional group of alcohols
-OH
where can the OH be attached on a carbon chain
- either the middle or the end
- we use a number to show where it is on the atom
- starts from right to left
describe the method for the hydration of ethene
- ethene gas is mixed with steam (h20) under the following conditions:
- 300 c
- 65 atm pressure
- catalyst of phosphoric acid
what is the raw material used for the hydration of ethene
crude oil provides the ethene
what are the advantages of the hydration of ethene
- makes pure ethanol
- can run continuously
what are the disadvantages of the hydration of ethene
- conditions require a lot of energy
- non-renewable raw material used
describe the method for the fermentation of glucose
- glucose is fermented microbiologically under the following conditions:
- yeast (provides enzymes)
- 30 c enzymes optimum temp
- anaerobic prevents oxidation
what is the raw material used for the fermentation of glucose
sugar cane provides the glucose
what are the advantages of fermenting glucose
- renewable raw material used
- conditions not energy intensive
what are the disadvantages of fermenting glucose
- makes impure ethanol
- must be done in individual batches
in what ways can ethanol be oxidised
- combustion
- microbial oxidation
- chemical oxidation
describe the combustion of ethanol
- combusts completely because of the oxygen atom in the OH group
- this results in a non-luminous blue flame
-C2H5OH + 3O2 -> 2Co2 + 2H2O
describe microbial oxidation of ethanol
- micro-organisms such as fungi and bacteria use the oxygen in the air to oxidise ethanol into ethanoic acid
- this can only happen if aerobically
- we can represent the microbial use of oxygen in the equation with the [O] symbol
-C2H5OH + 2[O] -> CH3COOH + H2O
describe chemical oxidation of ethanol
- to oxidise it in a lab we heat it with:
- potassium dichromate(VI) (K2CR2O7)
- dilute sulphuric acid ( H2SO4)
- with microbial oxidation, this forms ethanoic acid and we use an [O] symbol to write an equation for the reaction
- as this occurs the orange dichromate ions are turned into green chromium(III) ions
what is the functional group of carboxylic acids
- COOH
how is vinegar formed
- its an aqueous solution of ethanoic acid
- it forms when ethanol in wine undergoes microbial oxidation
- C2H5OH + 2[O] -> CH3COOH + h2O
what is carboxylic acids behaviour as an acid
- they lose their H+ and become negatively charged
- the name changes from ‘oic acid’ to ‘oate’ in the salt
give the equation for carboxylic acids reaction with metals
- acid + metal -> salt + hydrogen
observations when carboxylic acids react with metals
effervescence: due to the hydrogen gas being produced
- solid disappears: due to the metal being used up in the reaction
give the equation for methanoic acid reacting with sodium
methanoic acid + sodium -> sodium methanoate + hydrogen
give the equation for carboxylic acids reactive with metal carbonates
acid + metal carbonate -> salt + water + carbon dioxide
observations when carboxylic acids react with metal carbonates
- effervescence: due to the carbon dioxide gas being released
- solid disappears: due to the metal carbonate being used up in the reaction
give the equation when methanoic acid reacts with sodium carbonate
methanoic acid + sodium carbonate -> sodium methanoate + water + carbon dioxide
what is the definition of an ester
esters are a family of organic molecules which form when a carboxylic acid and an alcohol join together by losing an H2O molecule
what is the functional group of an ester
-COO-
describe what esters do
- they sit between 2 carbon chains, joining them together
- doesnt matter what those carbon chains look like
- they are represented by a question mark
what is the equation of an Ester ?
carboxylic acid + alcohol -> ester + water
what are the names called for making an ester ?
- condensation
- esterification
describe the method for making an ester
- mix the carboxylic acid and alcohol together
- add a few drops of concentrated sulphuric acid
- warm it for a while
- tip the mixture into sodium carbonate solution
- this neutralises the catalyst which is corrosive otherwise
- this reaction produces co2 so you wait till the fizzing stops
what is the catalyst for making an ester ?
concentrated sulphuric acid
what are esters used in for everyday life
- they are volatile compounds so they have distinctive smells
- good for food colourings
- perfumes
how do you chose the correct carboxylic acid and alcohol to make a particular ester
draw it out and split it down the middle where the oxygen atom is inline with the carbon chain
define a polyester
- a polyester is a polymer made of lots molecules joined together in a chain by ester groups
- to make an ester you need two types of monomer
how do you draw a polyester if lots of monomers join into a long chain repeating themselves
you draw a repeat unit of just one of them with brackets round it with the line coming through the bracket
when using a repeat unit what is this type of polymerisation called
- condensation polymerisation because each time a monomer joins the end of a chain an h2o molecule is lost
how can you create any polyester you want ?
by choosing the correct dicarboxylic acid and diol because the carbon chains between the -COOH- and -OH groups in the monomers don’t change
how do you work out the stricture of the repeat unit ?
- highlight the OH in the -COOH- groups
-highlight the H in the -OH groups - get rid of them and join what’s left together
what are bio polyesters and what are the advantages
- some polyesters are biodegradable
- microbes such as bacteria and fungi use enzymes to break down the polymer into tis monomers and use them as energy supply
- this reduces landfill and incineration to dispose of used polyesters
