Untitled Essay, Research Paper

The intent of this laboratory assignment was double, foremost, we were to

show the extraction of acids and bases, eventually, finding what terra incognitas were

present. Second, we were to pull out caffeine from tea. These two assignment will be

documented in two separate entities.Introduction: Acid/base extraction involves transporting out simple acid/base reactions in

order to divide strong organic acids, weak organic acids impersonal organic compounds

and basic organic substances. The process for this laboratory assignment are on the

following pages.3 ) Separation of Carboxylic Acid, a Phenol and a Impersonal Substance The intent of this acid/base extraction is to divide a mixture of

equal parts of

benzoic acid ( strong acid ) and 2-naphthanol ( weak base ) and

1,4-dimethoxybenzene ( impersonal ) by pull outing from tert-butylmethyl quintessence ( really

volatile ) .The end of this experiment was to place the three constituents in the mixture

and to find the per centum recovery of each from the mixture.4 ) Separation of a Neutral and Basic Substance A mixture of equal parts of a impersonal substance incorporating either

naphthalene or

benjamin and a basic substance incorporating either 4-chloroaniline or ethyl 4-aminobenzoate

were to be separated by extraction from an ether solution. Once the separation took

topographic point, and crystallisation was carried out, it became possible to find what

constituents were in the unknown mixture, by agencies of a thaw point finding.

Consequences

Procedure Observations InferenceDissolve 3.05g Phenol Mixture was a golden-

Impersonal acid in 30ml brown/yellow colour

t-butyl methyl quintessence in

Erlenmeyer flask and transportation

mixture to 125ml separatory

funnel utilizing small quintessence to

finish the transferAdd 10 milliliter of H2O

Organic layer=mixture

aqueous layer=water ( clear ) Add 10 milliliters saturated aqueous Sodium

hydrogen carbonate NaHCO3 dissolves in

solution Na hydrogen carbonate

H2O.

to funnel and blend carefully

with stopper onVent liberated C

Carbon dioxide gas

dioxide and agitate the mixture was released three times

exhaustively with frequent venting

of the funnelAllow beds to divide Layer = H2O +NaHCO3

wholly and pull off

lower bed into 50ml Erlenmeyer

flask 1Add 10ml of 1.5 aqueous NaOH Flask 2 = H2O + NaHCO3

( 5ml of 3M and 5ml H2O ) to

separatory funnel, agitate mixture,

allow beds to divide and pull

off lower bed into a 25ml

Erlenmeyer flask 2. Add extra

5ml of H2O to funnel, agitate as beforeAdd 15 milliliter NaCl to funnel. Shake Bottom bed is white and

NaCl was added to

the mixture and let beds to divide gooey. rinse the quintessence

and pull off lower bed, which is bed and to take

discarded organic substances

NaOH and NaHCO3

Pour ether bed into 50ml

Erlenmeyer flask from the top

of the separatory funnel

( non leting any H2O

droplets to be transferred )

Flask 3Add anhydrous NaSO4

to ether infusion until it no

longer bunchs together

and put it asideAcidify contents of flask 2 Litmus went from

Acidification was now

by dropwise add-on of blue to tap.

Flask complete

concentrated HCl while 2 = creamy colour

proving with litmus paper

and cool in iceAcidify contents of flask 1 Litmus went from

Acidification was now

by adding HCl dropwise blue to tap. Flask

complete

while proving with litmus 2 = white solution

paper and cool in iceDecant quintessence from flask

3 into a tared flaskBoil quintessence with boiling chipsDo a vacuity filtration and Solution bends

to a Crystallization is now

recrystallize quintessence by fade outing it solid. complete

in 5ml, taking out boiling french friess,

adding beads of Ligroin until the

solution was cloudy and cool it

in iceIsolate crystals from flask 2 by Crystals = cream-colored Dried crystals

are now

vacuity filtration and wash with pulverization

ready for runing point

a little sum of ice H2O

finding

and recrystallize it from boiling

waterRepeat the above for flask 1 Crystals = white

powderFlasks figure 4 and 5 were done by the undermentioned diagram.

Consequences: As a consequence of this acid/base experiment, the undermentioned consequences were obtained:

Flask 1: 31.113g

-30.223g

.890g

Flask 2: 36.812g

-36.002g

.810g

Flask 3: 90.789g

-90.114g

.065g

% output = experimental weight x 100 %

theoretical weight

Flask 1: .890g x 100 % = 89 %

1.00g

Flask 2: .810g x 100 % = 81 %

1.00g

Flask 3: .675g x 100 % = 67.5 %

1.00g

When taking the runing points of the terra incognitas, flasks 4 and 5, I came

to the

decision that the samples contained, benjamin, runing point of 136-137Degrees ( C ) and

4-chloroaniline, runing point of 67-80 grades ( C ) , respectively.Flask 4: 90.912g

-89.174g

1.738g % output = 1.738g ten 100 % = 90.4 %

1.922g

Flask 5: 87.833g

-86.064g

1.769g

% output = 1.769g ten 100 % = 87.3 %

2.027g

Decision: After each process was complete, it became evident that fla

sk figure

4 and

flask figure 5 contained benjamin and 4-chloroaniline, severally. The thaw point

scope that was by experimentation determined for each was 136-137 for benjamin and 67-70

for 4-chloroaniline. As you can see, this experiment was non error-free, as my per centum

output was non 100 % . This is expected for any experiment ; for there is no manner that, under

the conditions, this experiment can be free of mistake. This mistake could hold occurred for

many grounds. The most prevailing ground, I feel that possibly non all of the substance was

transferred from the flask to the vacuity, giving a little mistake. Besides, some residue could

hold besides been left in the vacuity funnel when reassigning the crystal substances.

Questions2 ) It is necessary because nil would come out of the stopcock- the ground for this is

because of force per unit area. Leaving the stopper on, would diminish the force per unit area forcing down

on the liquid and the force per unit area forcing upward would predominate, leting nil to escape.3 ) I would non anticipate p-nitrophenol ( pka = 7.15 ) to fade out NaHCO3 ( pka = 6.4 ) because

holding a weak acid and a weak base, the reaction would prefer the merchandises, non the

reactants, hence, the reaction would non continue frontward. I would anticipate

2,5-dinitrophenol ( pka = 5.15 ) to fade out in NaHCO3 the reaction would continue

forward.5 ) a ) 1g benzoic acid x 1mol = .00699 mol benzoic acid

143g benzoic acidb ) 1ml 10 % solution NaHCO3 x 1g_ ten 1mol = .00116 mol NaHCO3

4ml 96g NaHCO3

.00699 moles of benzoic acid

Introduction: The intent of the 2nd portion of this laboratory assignment was to

infusion

caffeine from tea utilizing methylene chloride and so to corroborate the individuality of it by

fixing a derived function of the extracted caffeine which has a crisp thaw point, unlike

caffeine itself. Once the extraction was complete, we were to prove for runing point and

acquire a HPLC reading for our derivative.Discussion: Tea leaves contain acidic, coloured compounds every bit good as a little sum

of

good chlorophyll, which is soluble in methylene chloride. Caffeine can be easy

extracted from tea. This process can be done utilizing conventional methods. Simply

pouring hot H2O on the tea bags and immersing the bags for about 5-7 proceedingss would

infusion most of the caffeine that the tea contains. Pure caffeine itself is a white,

bitter,

odourless crystalline solid, hence, it is obvious that more than merely caffeine is in

the

liquid tea solution since tea is a brown colour. Because of this, methylene chloride is used

to

fade out the caffeine that is in the tea, which leaves the other components in the

aqueous

bed. Using a separatory funnel, it becomes possible to pull out the dissolved caffeine

from the aqueous bed and the extraction is now ready for farther process.

Consequences

Procedure Observation InferenceTo a 250ml beaker

incorporating 7 tea bags,

add 100ml of boiling

water.Allow the mixture to stand Brown aqueous

solution

for 5-7 proceedingss while immersing incorporating caffeine and

the tea from the bags other impurities.Decant the mixture into

another flaskCool solution to approach

Dichloromethane =

room temperature and

H2O soluble, clear,

extract twice with 15ml heavier that H2O.

parts of methylene chloride

utilizing a soft rocking gesture

and venting. Drain off methylene chloride Dichloromethane

Vaporization of the

bed on first extraction ; organic bed found

solvent foliages crude

include emulsion bed on on the underside of

the caffeine, which on

the 2nd extraction.

funnel where the sublimation, outputs

caffeine is dissolved. a comparatively pure

Chlorine = top, aqueous merchandise.

solution.Drain extraction 1 and 2

back into the funnelDry combined dichloromethane The dissolver bed is

solutions and any emulsion yellow.

bed with Na sulfateWash the drying agent

Residue of light-green

with farther parts of white crystalline

weighs

dissolver and steam bath 50mg ( solid )

the solventTo 5mg of the

Salicylic acid is H2O

sublimed caffeine in H2O soluble.

beaker, add 7.5mg of

salicylic acid and.5 milliliter

of dichloromethane.Heat mixture to a furuncle Petroleum quintessence is a hapless

and add a few beads dissolver for the merchandise.

crude oil quintessence until

the mixture turns cloudy.Insulate beaker and let

it to chill easy to room

temperature and so chill

in an ice bathRemove the dissolver with Needle-like crystals are

Caffeine salicylate is

a Pasteur pipette while the stray ( white colour )

formed.

beaker is in the ice bath

so vacuity filter.

Caffeine beaker: 51.61g

-51.56g

.05g = 50mg

% output = .05g x 100 % = 20 %

.25g

Caffeine salicylate: 17.198g

-17.036g

.062g % output = .062g x 100 % = 25 %

.25g

Decision

Harmonizing to the HPLC graph that follows, my merchandise was really pure. The

existent

runing point of caffeine salicylate is 137 grade ( C ) , my merchandise was found to hold a

runing point of 138 grades ( C ) . As before, of class this experiment was non done

wholly error-free, the mistake is due about wholly on human mistake.