Lab 6- Soap and Detergent

TABLE OF CONTENT

NOCONTENTPAGE

1Table Of Content2

2Abstract3

3Introduction3

4Objectives5

5Theory5

6Apparatus8

7Procedures9

8Results12

99Sample of calculations-

10Discussions15

11Conclusions16

12Recommendations16

13References17

14Appendices18

ABSTRACTThe experiment was conducted to prepare soap. The properties of the prepared soap are then compared with the synthetic detergent. The properties that are being compared are the precipitation, emulsification and cleaning abilities. From the experiment that had been conducted, it can be conclude that soap has the properties of emulsifying oil whereas the detergent does not. Besides that, the abilities of forming precipitate can also be seen clearly in the soap solution whereas the detergent does not forms any precipitate. Thus, the experiment is completed and is successfully conducted.INTRODUCTIONSoap is manufactured much like it was back then, where fats and oils are technically heated with the presence of a strong base to produce fatty acid salts and glycerol in a process termed as saponification. As the matter of fact, the salt of a fatty acid is the soap, which is soft and waxy material that brush up the ability for cleaning purpose of water. A positive ion, usually Na+ or Ka+, and a negative ion usually the anions of long-chained carboxylic acids yielded by hydrolysis of either animals or vegetables fats.In other words, soaps is a generic term of sodium or potassium salts of long-chain organic acids made from naturally occurring esters in animal fats and vegetables oils. All organic acids contain CRCO2H functional group, where R is a shorthand notation for methyl, CH3-, ethyl CH3CH2-, Propyl, CH3CH2-CH2-, or more complex hydrocarbon chains called alkyl groups. Chemists use the R shorthand notation because the group are very large and the hydrocarbon chain has little effect on the compounds chemical reactivity. All esters contain RCO2R functional group.The R groups in soaps are hydrocarbon chains that generally contain 12 to 18 carbon atoms. Sodium fatty acids such as lauric (vegetable oil) palmatic (palm oil) and stearic (animal fat) acids are just a few examples of soaps The hydrocarbon chain in soaps may contain saturated or unsaturated chains. Sodium salts are usually solid therefore; most bars of soap are of sodium salts. Potassium salts are the basis of liquid soaps, shaving creams, and greases. Fats and vegetable oil are triglycerides. Triglycerides in an ester derived from fatty acids. Saponification is the basis hydrolysis of an ester producing a carboxylic acid salt and an alcohol. A lone pair of electrons on the OH- is attracted to the partially positively charged C atom in the C=O bond in the ester. The C-OR bond breaks generating a carboxylic acid (RCO2H) and an alcohol (ROH). In the presence of carboxylic are converted to their sodium salts (RCO- Na+).During World War 1, the first synthetic detergent has been produced, mainly because of the urge to find another cleaning agent that would react in hard water. A variety of detergents can be found today, which generally contain surfactants, a builder, and other additives such as bleaching agents and enzymes. The surfactants are the parts that are responsible for the cleaning properties of that particular detergent. Some of them may be ionic, cationic or even non-ionic. The builders indeed are compounds responsible for removing the corresponding calcium and magnesium ions in hard water.However, there are two detergents which may not be as safe as it may concern, mostly that contains phosphates. Such detergents will end up in wastewater and cause excessive growth of algae and other aquatic plants. When those die, bacteria that present in the dead matter consume oxygen which results in the lack of oxygen left for the fish and other aquatic lives.OBJECTIVESThe purposes of conducting this experiment are to prepare soap with using mineral oils and to study and compare the properties of soap and synthetic detergent.THEORYSoap is the salt of weak acid. Most organic acid are weak acids. Soap is a mixture of sodium salts of various naturally occurring fatty acids. The general formula for fat is shown as the figure below, where R-COOH represents fatty acid.

Soap is produced through saponification process where the fatty acid are reacted with sodium salts. A generalized saponification reaction is shown below:

The cleansing action of soaps results from two effects. Soaps are wetting agents that reduce the surface tension of water, allowing the water molecules to encounter the dirty object. They are also emulsifying agents. Dirt frequently consists of grease oil along with other organic species. In general, the organic species are non-polar. Water is a polar species. Thus, these two cannot dissolve in each other. However, soaps cross the boundary between polar and non-polar. Soaps molecule consists of a long non-polar tail (the hydrocarbon chain of fatty acid) and a highly polar end (the ionic group COO -). The non polar site, also called as the hydrophobic tail (water hating) is able to dissolve the grease and dirt whereas the polar or hydrophilic end (water loving) is attracted to water molecules.

The non- polar portion of the soap is commonly represented with a zigzags line and the polar head with a circle. Non-polar PolarA micelle, a spherical shape is formed resulting from the negatively charged heads of the soap molecules. They then orient themselves, where the non-polar tails rearrange towards the centre of the micelle and the hydrophilic site facing the water. In the presence of oil or dirt, the non-polar head interact with them, and gathered it to the centre of the micelle. This is how soap cleans technically. When rinsed with water, the micelle together with the dirt washed away. Soap is theoretically acting as an emulsifying agent, where emulsion is the dispersion of a liquid in a second immiscible liquid.

WATER

Water supplies in certain areas are acidic as a result of acid rain or pollution, or hard due to the dissolved mineral content. Both acidic and hard water reduced the cleansing action of the sop. Soap is the salt o a weak acid. With the presence of stronger acid, the sodium salt is converted to an insoluble organic acid.

APPARATUS Test tubes with rack pH meter beakers measuring cylinder stirrer hot plateMATERIALS Stock soap solution Distilled water Synthetic detergent (dynamo) Mineral oils CaCl2 solution, MgCl2 solution, FeCl2 solution 1 M HCl Tomato sauce Cloth strip

PROCEDUREPart A: Soap preparation1. 25 mL of vegetable oil is placed in a 250-mL Erlenmeyer flask. 20 mL of ethanol and 25 mL of 6 M sodium hydroxide solution are added to the flask. The mixture is stirred using a stirring bar to mix the contents of the flask2. The 250-mL flask is heated in a 600 mL boiling-water bath.3. The mixture is stirred continuously during the heating process to prevent the mixture from foaming. If the mixture should foam to the point of nearly overflowing, the flask is removed from the boiling-water bath until the foaming subsides, then heating is continued. The mixture is heated for 20-30 minute or until the alcohol odor is no longer detectable.4. The paste-like mixture is removed from the water bath and the flask is cooled in an ice bath for 10-15 minutes.5. While the flask is cooling, the vacuum filtration apparatus is assembled as shown in the figure below. The vacuum flask is secured to a ring stand with a utility clamp to prevent the apparatus from toppling over.

6. A piece of filter paper is weighed to the nearest 0.001 g and the mass is recorded. The filter paper is placed inside the Buchner funnel. The paper is moistened with water so that it fits flush in the bottom of the funnel.7. Once the flask has cooled, 150 mL of saturated sodium chloride (NaCl) solution is added to the flask to "salt out" the soap.8. The water at the aspirator is slowly turned on. The mixture from the flask is poured into the Buchner funnel. Once all of the liquid has filtered through the funnel, the soap was washed with 10 mL of ice-cold water. The suction filtration is continued until all of the water is removed from the soap.9. The soap is removed from the funnel and pressed between two paper towels to dry it. The filter paper and dried soap are weighed, and the mass is recorded to the nearest 0.001 g and the mass of the soap determined by difference and the mass is then recorded.Part B: Comparison of soap and detergent properties- precipitation and emulsification.1. A stock soap solution is prepared by dissolving 2g of the prepared soap in 100 mL of boiling, distilled water. The mixture is stirred until the soap has dissolved and the solution is allowed to cool.2. Step 1 is repeated using 2 g of synthetic detergent. When both solutions are cool, the pH of each solution is determined using pH paper. 3. Three test tubes are labeled as test tube 1, 2, and 3. 4 drops of mineral oil are added to each test tube. 5 mL of distilled water is added to test tube 1. 5 mL of stock soap solution is added to test tube 2. 5 mL of stock synthetic detergent is added to test tube 3.4. Each solution is mixed by shaking and let stand for three to five minutes. The solutions, if any, which emulsifies the oil by forming a single layer, is noted. 5. The mixtures are poured into the Waste Container. The three test tubes are cleaned and dried.6. Three more test tubes are labeled as test tube 1, 2, and 3. 2 mL of stock soap solution is placed in each of the three test tubes. 2 mL of 1% CaCl2 solution is added to test tube 1. 2 mL of 1% MgCl2 solution is added to test tube 2. 2 mL of l% FeCl2 solution is added to test tube 3. Each test tube is shaken to mix the solutions. The observations are recorded.7. 4 drops of mineral oil are added to each of the test tubes in Step 6. Each test tube is shaken to mix the solutions and the solutions are left to stand for three five minutes. The solutions, if any, which emulsifies the oil by forming a single layer, is noted. 8. Steps 6-7 are repeated using 2 mL of stock detergent solution. The solutions that precipitated are observed. 9. The solutions, if any, which emulsifies the oil by forming a single layer, is noted. 10. The mixtures are poured into the Waste Container. The test tubes are cleaned and dried.11. 5 ml of stock soap solution is poured in cine clean test tube and 5 mL of stock detergent solution in a second test tube. 1 M HC1 is added one drop at a time to both solutions until the pH in each test tube is equal to 3. The number of drops of acid added to each mixture is counted. Any precipitate formed in either mixture is observed.12. 1 drop of mineral oil is added to each test tube in Step 11. Each test tube is shaken to mix the solution. Any emulsification formed in either mixture is observed.Part C: Comparison of cleaning abilities of soap and detergents1. The three beakers are cleaned, dried and labeled. Then 20 mL of stock soap solution (from Step 1 in section 7.4.2) is placed in the first beaker. After that, 20 mL of stock detergent solution (from Step 2 in Part B) is placed in the 2nd beaker. 20 mL of a commercial liquid is added in a third beaker.2. Three cloth test strips that have been soaked in tomato sauce are obtained and then one strip is placed in each of the beakers. Repeatedly each solution is stirred with a stirrer bar for 5 minutes.3. The cloth strips is removed from the soap and detergent solution and then the excess water is squeezed out. Each cloth strip is observed and compared to determine their relative cleanliness.RESULTSSoap preparationMass of filter (g)0.591

Mass of filter paper + soap (g)30.177

Mass of soap recovered29.586

Soap

Comparison of soap and detergent propertiesBrand name of synthetics detergentDynamo

pH of soap solution10.05

pH of synthetics detergent solution7.51

Test tubeObservations

4 drops of oil + 5mL of distilled water oil droplets formed

Oil layer formed

4 drops of oil + 5mL of soap solution oil dissolves in solution

Oil emulsified

4 drops of oil + 5mL of detergent solution very tiny oil droplets and bubbles formed

Tiny oil droplets formed

SystemPrecipitateOil emulsified

SoapXSoapX

CaCl2x

MgCl2x

FeCl3x

AcidicxXx

Reaction of stock soap with CaCl2, MgCl2, and FeCl3

Reaction of synthetic detergent with CaCl2, MgCl2, and FeCl3

Number of drops of acidDetergent(3 drops)3.913.212.73

Soap(5 drops)6.926.283.102.64

Cleaning abilitiesMaterialsCleaning abilities

SoapClean

Stock detergent Most clean

Detergent Clean

Cleaning abilities of stock soap, synthetic detergent and detergent

DISCUSSIONWater that contains calcium ions, Ca2+, and magnesium ions, Mg2+, is said to be hard water. These ions are leached from ground water flowing over rock formations containing limestone and other minerals. Hard water interferes with the cleaning action of soaps. From the observation of the lab conducted, the soap formed precipitates in all of the solutions added (CaCl2, MgCl2 and FeCl2) as well emulsifies the oil. This may not appear as good characteristic for soap as a cleaning agent if it forms precipitate and emulsifies oil on cloth.When soap is added to hard water, insoluble compounds or precipitate are formed. However, when the water containing these ions is boiled, hard water leaves a deposit of calcium carbonate, CaCO3. This scale can be seen builds up in tea kettles and inside hot water heaters.Different from soaps, detergent has the abilities to dissolve these compounds causing no precipitate to be formed. Detergent is a better cleaning agent as it forms no precipitation and does not emulsifies the oil. Thus, grease and dirt can be cleaned without involving any precipitation or oil emulsification. Nowadays, it can be seen that detergents have undeniably replaced soap for many cleaning jobs. However, some of these synthetic detergents are not biodegradable.CONCLUSIONThe soap is successfully prepared. The properties of the soaps which are precipitation, emulsification and cleaning abilities were compared with detergent through this experiment. The results and changes are observed.In a nutshell, we can conclude that soap has the abilities to emulsify oil whereas detergent does not. The soap will also form precipitate whereas detergent does not. This may not appear as good characteristics for soap as a cleaning agent. RECOMMENDATIONSThere are a few recommendations that will improve observations.Firstly, the experiment should at least be repeated twice in order to get more accurate observations. The observations might be more convincing if the average is taken.Secondly, the pH reading must be conducted at same temperature for pH is varying at different temperatures. Avoid contact with any chemical reagents involved. REFERENCES Experiments in General Chemistry Featuring Measuring Net, Bobby Shanton, Lin Zhu, C.H. Atwood, 2005, Brooks/Cole Laboratory Series, USA. Organic Chemistry (third edition), R. T. Morrison & R. N. Boyd,1973, Allyn and Bacon, Boston. Fundamentals of General, Organic and Biological Chemistry (third edition), J. McMurry, M.E. Castellion, 1999, Prentice Hall, Inc. Upper Saddle River, New Jersey.

2