To the constituents of a fake pharmaceutical readying. Panacetin. and placing the unknown constituent of the mixture through extraction and separation methods.
To larn how to sublimate by recrystallization. how to dry them and how to obtain a thaw point.
Precaution: ACETANILIDE AND PHENACETIN ARE EYE AND SKIN IRRITANTS. Minimize contact with your unknown compound.
Theory:
In this experiment. Panacetin. a pharmaceutical readying will be separated from its constituents by doing usage of their solubilities and acid-base belongingss. Panacetin contains acetylsalicylic acid. saccharose and an unknown constituent that may be either acetanilide or phenacetin. Of the three constituents. merely sucrose is indissoluble in the organic dissolver methylene chloride ( CH2Cl2 or methylene chloride ) . The indissoluble saccharose can be filtered out if Panacetin is dissolved wholly in methylene chloride by gravitation filtration or centrifugation go forthing the soluble acetylsalicylic acid. phenylacetamide and acetophenetidin in the solution.
Although the phenylacetamide and acetylsalicylic acid are both rather indissoluble in H2O at room temperature. the Na salt of acetylsalicylic acid is really soluble in H2O but indissoluble in methylene chloride. Aspirin. which is a strong acid can be converted to the salt. Na acetylsalicylate by extraction with an aqueous solution of Na hydrogen carbonate. This salt will migrate from the methylene chloride bed. in which it is indissoluble. to the aqueous bed. in which it is soluble. The unknown constituent will remain behind in the solution and can be isolated by vaporizing the dissolver from the methylene chloride solution. Adding HCl to the aqueous solution restores aspirin as an indissoluble white solid.
In the 3rd experiment. the individuality of the unknown constituent of Panacetin will be purified. Purification is necessary because the separation process may be imperfect go forthing hints of little measures in the compound after separation or chemical reactions may happen prior to or during the separation adding new drosss. The unknown constituent can be purified by recrystallization. in which an impure solid dissolves in a hot ( normally boiling ) dissolver so crystallizes from the cooled solution in a purer signifier.
Methods/Procedures:
This experiment was followed from the text edition on pages 52-53 for experiment 2 and 59-60 for experiment 3 excepting the microscale portion. First. weigh about 3. 00 g of Panacetin and reassign it to a clean. dry 125 milliliter Erlenmeyer flask. Add 50 milliliter of methylene chloride to the flask. stir the mixture with a stirring rod to interrupt up any balls. When it appears that no more of the solid will fade out. filtrate the mixture by gravitation. Roll up the undissolved solid on the filter paper and set it aside to dry. Once it has wholly dried. reweigh the solid. This compound separated by gravitation filtration is known as saccharose.
Following. reassign the filtrate to a separatory funnel and pull out it with two 30 ml parts of 5 % Na hydrogen carbonate. For each extraction. utilize a stirring rod to stir the liquid bed until any foaming subsides before a stopper is placed on the funnel and shaken. Dichloromethane will be on the bottom bed and will be drained to a different container. Transfer the methylene chloride bed back into the funnel for the 2nd extraction. The upper bed will be transferred in an Erlenmeyer flask and will be used for recovery of phenylacetamide. Unite the two aqueous solutions in the same container and sour easy with 6M HCL to convey it to a pH of 2. Cool the mixture to room temperature or below while twirling the flask on occasion in an ice bath. Roll up the acetylsalicylic acid by vacuity filtration. Wash the acetylsalicylic acid on the filter with cold distilled H2O. Dry the sample exhaustively before weighing and go forth it in the goon for the following lab agenda.
Before continuing to recrystallization. triturate the compound with 20 milliliters of hexane. Oppress the solid with a stirring rod and filter. Recrystallize the unknown drug constituent from experiment 2 by boiling it with merely adequate H2O to fade out it wholly. so allowing it cool to room temperature so to 0 C. In order to bring on crystallisation. it would be helpful to rub the walls of the flask so that crystals would hold a surface to attach to. Use vacuum filtration to insulate the sample so dry the merchandise to a changeless mass and weigh in a tared phial.
Crunch a little sum of the dry unknown constituent to a all right pulverization on a ticker glass utilizing a spatula. Divide the solid into four equal parts. Combine parts 1 and 2. Mix part 3 with an about equal sum of finely land acetanilide and blend part 4 with an about equal sum of finely land acetophenetidin. Obtain the thaw point ranges of the purified unknown ( parts 1 and 2 ) . mixture with phenylacetamide and mixture with acetophenetidin. Each runing point should be measured on two samples- more than that if liquescent points are imprecise or accurate.
Safety Issues: ( all of these are taken from MSDSonline. com )
Acetanilide
Potential Acute Effects: Hazardous in instance of oculus contact ( irritant ) . of consumption. of inspiration. Slightly risky in instance of tegument contact( thorn ) .Potential Chronic Health Effectss: Hazardous in instance of oculus contact ( irritant ) . of consumption. of inspiration. Slightly risky in instance of tegument contact ( irritant ) .
- PhenacetinEye and tegument thorn
- Methylene chloridePotential Health Effectss
Inhalation:Causes annoyance to respiratory piece of land. Has a strong narcotic consequence with symptoms of mental confusion. light-headedness. weariness. sickness. emesis and concern. Causes formation of C monoxide in blood which affects cardiovascular system and cardinal nervous system. Continued exposure may do increased light-headedness. staggering. unconsciousness. and even decease. Exposure may do the symptoms of angina ( chest strivings ) worse. Consumption:
May cause annoyance of the GI piece of land with purging. If purging consequences in aspiration. chemical pneumonia could follow. Absorption through GI piece of land may bring forth symptoms of cardinal nervous system depression runing from light headedness to unconsciousness.
Skin Contact:Causes annoyance. inflammation and hurting. Prolonged contact can do Burnss. Liquid degreases the tegument. May be absorbed through tegument.Eye Contact:Bluess can do oculus annoyance. Contact can bring forth hurting. redness andtemporal oculus harm.Chronic Exposure:Can do concern. mental confusion. depression. liver effects. kidney effects. bronchitis. loss of appetency. sickness. deficiency of balance. and ocular perturbations. Can do dermatitis upon drawn-out tegument contact. Methylene chloride may do malignant neoplastic disease in worlds. Aggravation of Preexistent Conditionss:
Persons with preexistent tegument upsets. oculus jobs. impaired liver. kidney. respiratory or cardiovascular map may be more susceptible to the effects of this substance.
AspirinEye Contact: Moderate Eye Irritation: Signs/symptoms may include inflammation. swelling. hurting. lacrimation. and blurred or brumous vision. Skin Contact: Moderate Skin Irritation: Signs/symptoms may include localised inflammation. swelling. itchiness. and waterlessness. May be absorbed through tegument and cause mark organ effects. Inhalation: No wellness effects are expected.Consumption:May be harmful if swallowed.Gastrointestinal Irritation: Signs/symptoms may include abdominal hurting. sickness. diarrhoea and emesis. Repeated consumption may do:Maybe absorbed following consumption and cause mark organ effects. Target Organ Effectss: Prolonged or repeated exposure may do:Auditory Effects: Signs/symptoms may include hearing impairment. balance disfunction and tintinnabulation in the ears. Cloting Disorders: Signs/symptoms may include increased blood curdling clip and internal hemorrhage ( bleeding ) . Liver-colored Effectss: Signs/symptoms may include loss of appetency. weight loss. weariness. failing. abdominal tenderness and icterus.
Central Nervous System ( CNS ) Depression: Signs/symptoms may include concern. giddiness. sleepiness. incoordination. sickness. slowed reaction clip. slurred address. silliness. and unconsciousness. Kidney Effects: Signs/symptoms may include reduced or absent urine production. increased serum creatinine. lower back hurting. increased protein in urine. and increased blood urea N ( BUN ) . Pneumonic Edema: Signs/symptoms may include chest uncomfortableness. shortness of breath. important cough with bubbling phlegm production. blue colored tegument ( cyanosis ) . increased bosom rate. respiratory failure and may be fatal. Single exposure may do:
Immunological Effectss: Signs/symptoms may include changes in the figure of go arounding immune cells. allergic tegument and /or respiratory reaction. and alterations in immune map.
Sodium Bicarbonate
EMERGENCY OVERVIEWWarning! May do respiratory tract annoyance. Causes oculus and skin annoyance. Target Organs: Blood. kidneys. bosom. liver. eyes. tegument.Potential Health EffectssEye: Causes oculus annoyance.Skin: Causes skin annoyance. May be harmful if absorbed through the tegument. Consumption: May be harmful if swallowed. Causes GI piece of land annoyance. Inhalation: May do respiratory tract annoyance. May be harmful if inhaled. Chronic: May do liver and kidney harm. Adverse generative effects have been reported in animate beings. Lab experiments have resulted in mutagenic effects. Chronic exposure may do blood effects.
Hydrochloric Acid
POTENTIAL HEALTH EFFECTS:Inhalation: May do annoyance ( perchance severe ) . chemical Burnss. and pneumonic hydrops.Skin contact: May do annoyance ( perchance severe ) and chemical Burnss.Eye contact: May do annoyance ( perchance severe ) . chemical Burnss. oculus harm. and sightlessness.Consumption: Not a likely path of exposure.
Target Organs Effected: Respiratory System. Skin. Eye
Chronic Effectss: Repeated or prolonged exposure to thin solutions may ensue in dermatitis. Stain of the dentitions may happen as a consequence of long term exposure.Interaction with Other Chemicals Which Enhance Toxicity: None known Medical Conditions Aggravated by Exposure: None known
Observations/Results:
In Experiment the extraction of substances from one another is based on the differences in their physical and chemical belongingss. Approximately. 3. 0029 g of panacetin was weighed and wholly dissolved in 50 milliliter of methylene chloride and filtered. The residue was left to dry and weighed ( sucrose ). Then 30 milliliter of NaHCO3 was added to the filtrate. This solution was transferred into a separatory funnel. This formed two beds. Top bed was the organic bed ( NaHCO3 ) described as a clear liquid. Bottom bed was the aqueous bed and was yellow in colour. The filtrate was washed twice with NaHCO3. HCl was added to the aqueous solution until the pH equaled to 2. 0. It was filtered through vacuity filtration and allowed to dry until the following week’s lab. This filtrate is known as acetylsalicylic acid. Meanwhile. the unknown in the organic bed was besides allowed to settle for the following experiment.
In experiment before we went to make recrystallization. we foremost did trituration of the unknown by adding 20 milliliter of hexane. We crushed the solid and filtered. Even with the add-on of about 27 milliliters of boiling H2O into the compound. it started to fade out. That was the first hint that we have acetanilide as our unknown. We went in front and go on warming and twirling the solution over a hot home base. There was the formation of brown oil-like globules. We were so asked to pour the clear liquid from this solution. This clear liquid was allowed to chill to room temperature so to 0 C. There was formation of white crystals at the border of the beaker. Through vacuity filtration. we were able to filtrate the merchandise. weighed and used for runing point measuring of the unknown.
The solid was divided into 4 equal parts. First 2 parts were combined. 3rd portion was assorted with acetanilide and the last portion was assorted with acetophenetidin. After taking the runing points of all these 3 substances we were able to place the unknown merchandise to be acetanilide.
No large issues encountered during this experiment. Transfering some merchandises every bit good as the concluding crystals from ticker glass and filter paper and go forthing some merchandises were important to acquire the most concluding merchandise. This explains why the per centum recovery for the unknown was low. Some crystals fell off or didn’t transportation to the filter paper. Even though the % recovery was comparatively low ( 88. 4079 % ) . this experiment still produced a 0. 6898 g of merchandise.
Discussion/Conclusion:
This experiment was focused on two chief aims. First. the analysis of panacetin to happen out what per centums of saccharose. acetylsalicylic acid and the unknown constituent it contains. Second. to happen out whether the unknown is acetanilide and acetophenetidin. A large portion of the composing of panacetin was made up of the unknown. We were able to find the composing of saccharose to be 17. 95 % . Aspirin 26. 93 % and the unknown to be 55. 12 % After following the experiment processs. we were able to sublimate through recrystallization the terminal merchandise to be acetanilide. This is an odourless white crystalline solid substance which has a runing point of 114 C. Our experimental value for acetanilide’s runing point was 117 which indicates that the consequence had a really narrow scope and stopping point to the literature value. I would therefore conclude that we had isolated a close to pure merchandise of acetanilide with small drosss present.
Describe any grounds that a chemical reaction occurred when you added 6 M HCl to the solution of Na acetylsalicylate
A chemical reaction took topographic point upon the add-on of 6M HCl to a solution of Na acetylsalicylate because a precipitate formed known as acetylsalicylic acid.
Explain why the alterations that you observed took topographic point.
The ascertained alteration took topographic point as a consequence of the acid responding with the salt organizing a compound indissoluble in H2O.
Describe any explain the possible consequence on your consequences of the undermentioned experimental mistakes or fluctuations. In each instance. stipulate the constituent ( s ) whose per centum ( s ) would be excessively high or excessively low.
After adding methylene chloride to Panacetin. you didn’t stir or agitate the mixture long plenty
Improper stirring or shaking of the mixture will ensue in uncomplete disintegration of the panacetin mixture. There will be loss of some solid analytes during filtration. The cured sums will be lower than they should be taking to a concluding per centum to be low.
During the NaHCO3 extraction you failed to blend the aqueous and organic beds exhaustively.
If the aqueous and organic beds were non exhaustively assorted the acid would stay in the solution and the extraction would be less efficient ensuing to a low per centum output.
You erroneously extracted the methylene chloride solution with 5 % HCl insteadthan 5 % NaHCO3.
If 5 % HCl is used alternatively of 5 % NaHCO3 that would protonate the acetylsalicylic acid and maintain it in the organic solution doing the acetylsalicylic acid. acetylsalicyclic acid.
Alternatively of utilizing pH paper. you neutralized the Na hydrogen carbonate solution to pH 7 utilizing litmus paper
At ph7 the hydrogen carbonate wouldn’t be able to move as a base and pull out a proton because at pH of 7 it would protonate itself so it wouldn’t be able to respond with acetylsalicylic acid.
Write a balanced reaction equations for the reactions involved
When aspirin dissolves in aqueous NaHCO3
C9H8O4 ( aq ) + NaHCO3 ( aq ) —– & gt ; C9H7O4Na ( aq ) + CO2 + H2O Weak acid weak base Strong Base Strong acid
When Aspirin is precipitated from a Na acetylsalicylate solution by HCL
C9H7O4Na + HCl ————-? C9H8O4 + NaCl Strong Base Strong acid Weak Acid Weak Base
Assuming that both reactions are self-generated under the standard conditions. label the stronger acid. stronger base. weaker acid and weaker base in each equation.
Experiment 3
- What is the minimal volume of boiling H2O needed to fade out 0. 200 g of acetophenetidin?
- About how much acetophenetidin will stay dissolved when the H2O is cooledto room temperature?
- Calculate the maximal mass of solid ( undissolved ) acetophenetidin that can be recovered when the cooled solution is filtered.
0. 200 g-0. 0125 g ( sum soluble in cold H2O ) = 0. 1875 g
An unknown compound X is one of the four compounds listed in table 3. A mixture of Ten with benzoic acid thaws at 89 C. a mixture of Ten with phenyl succinate thaws at 120 °C and a mixture of Ten with m-aminophenol thaws at 102 °C. Give the individuality of X and explicate your logical thinking.
Ten is phenyl succinate.When a compound mixes with a different compound. the runing point of the mixture will be lower than the runing points of either of the pure compounds. Establishing from the tabular array. the runing point of pure benzoic acid is 121 C but when assorted to X. it went down to 89 C. Likewise with O-toluic acid and m-aminophenol. Since the runing point of mixture Ten with phenyl succinate has a runing point of 120 C. the runing point of pure X must be equal or closer to 121. Blending Ten with phenyl succinate did non alter the thaw point therefore X must be phenyl succinate.
