Grading Soap: I will dissolve and shake a small bit of your soap in a bottle to see if it makes suds.
100: copious amounts of suds.
90: lots of suds, a little grease
80: some suds, some grease
70: a few suds, lots of grease
50: mostly grease, a little suds
0: Any soap with a pH higher than 8
100: copious amounts of suds.
90: lots of suds, a little grease
80: some suds, some grease
70: a few suds, lots of grease
50: mostly grease, a little suds
0: Any soap with a pH higher than 8
Safety first
If you haven't already looked up the MSDS for sodium hydroxide (cas 1310-73-2) you should do so now and summarize its hazardous properties in the procedures portion of your journal.
Most likely... if you do have an encounter it will be on your skin, if this happens, flush the affected area with plenty of water until your skin no longer feels slippery.
If it gets in your eyes, flush them with cold water for 15 minutes and call for the nurse and an ambulance.
**YOU SHOULD WEAR GLASSES AND GLOVES (dishwashing kind work great) while working on this project.
**DISPOSAL: leftover sodium hydroxide can go down the drain with plenty of water, leftover fats and oils can go in the trash.
Most likely... if you do have an encounter it will be on your skin, if this happens, flush the affected area with plenty of water until your skin no longer feels slippery.
If it gets in your eyes, flush them with cold water for 15 minutes and call for the nurse and an ambulance.
**YOU SHOULD WEAR GLASSES AND GLOVES (dishwashing kind work great) while working on this project.
**DISPOSAL: leftover sodium hydroxide can go down the drain with plenty of water, leftover fats and oils can go in the trash.
Materials list: you have some choices to make
1. Which fat will you saponify? (you can use ANY fat or oil derived from plants or animals. Mineral and motor oils are a no-go as they lack the "fatty" parts known as triglycerides. A 10 point bonus is available if you make your own instead of using pre-bought fats or oils. Most "fine" soaps these days use olive oil, and "super lather" soaps use palm oil. Most folks with experience use different combinations to make mixtures that take advantage of the different properties given by the different sources.
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TABLE 19-1, Caveman Chemistry p.241
Oil or Fat g NaOH/g fat g KOH/g fat Lard 0.1380 0.1935 Olive Oil 0.1340 0.1879 Shortening 0.1360 0.1907 Tallow 0.1405 0.1971 |
2. Choose your alkali: KOH makes soft or liquid soap, NaOH makes solid bar soap (I have plenty of NaOH in the lab, but it is cheaply bought as LYE in the grocery store... sometimes found in the drain cleaner section. ensure you avoid the name brands as they have perfumes and other contaminants that may ruin your soap) 15 bonus points if you produce and use your own POTASH.
3. A 2L soda bottle
4. A beaker (lab) or saucepan (home)
5. Hotplate (lab) or stove (home)
6. Balance (lab) or kitchen scale (home)
7. Beaker (lab) or glass cup (home)
8. Stir rod (lab) or plastic spoon (home)
9. Thermometer is best, but necessary
10. A CLEAN funnel
11. Strip of neutral litmus paper (I have these)
3. A 2L soda bottle
4. A beaker (lab) or saucepan (home)
5. Hotplate (lab) or stove (home)
6. Balance (lab) or kitchen scale (home)
7. Beaker (lab) or glass cup (home)
8. Stir rod (lab) or plastic spoon (home)
9. Thermometer is best, but necessary
10. A CLEAN funnel
11. Strip of neutral litmus paper (I have these)
Procedure
1. Choose your fat source and ensure you have 1/2 pound of it. Convert this to grams using 1 pound = 454 grams. SHOW YOUR CALCULATION and record the weight of your fat in your notebook for the soap project. If you blend more than one oil, record the masses separately.
2. Put your fat/oil into a beaker/saucepan
3. Heat your fat/oil until it melts(fat) or is warm to the touch(liquid oil)... continue the steps below while its heating.
4. Calculate how many grams of NaOH are needed to saponify the fat you have weighed out. Use unit factor analysis and table 19-1 above. SHOW YOUR WORK. No work = no credit. If you choose to blend different oils you need to do this for each oil/fat used. 5 point bonus for trying a mixture of oils.
5. Add up the total weights for your NaOH and multiply it by 0.95. This ensures that you don't have excess NaOH in your finished soap, it is far better to have your soap be a little extra greasy than to have your soap eat your skin away. Record this amount in your notebook, show your work.
6. Weigh out twice the amount of water as NaOH in a glass beaker. Record this in your notebook.
7. Stir the beaker of water and slowly add your NaOH, the solution should get hot as the ions form and release their bond energy.
8. Since oil and water don't mix... this next bit is tricky and requires specific temperatures. Allow both your fat/oil and your sodium hydroxide (NaOH) solution to cool to between 38 and 41 degrees Celcius (100-110 if you use Fahrenheit). NOT GETTING THIS RIGHT IS THE MOST COMMON REASON FOR FAILED SOAP. If you don't have a thermometer... you can judge them as about right when you can barely hold them in your bare hands without burning. This isn't recommended, but its possible.
9. Use a funnel to pour the fat into the 2L bottle.
10. Use the funnel to pour the sodium hydroxide solution into the 2L bottle.
11. Put the lid on the bottle and shake it until it looks like salad dressing.
12. If it starts to separate, shake it again, you want it to appear smooth and creamy.
13. When it no longer separates, let it sit for a few days. Depending on what you used, it could be ready in an hour or it could take several days to solidify.
14. Allow the soap to "cure" for a few days to harden (like poured concrete)... this will go faster if you keep the bottle warm. (best done by putting it into a pan of hot tap water ... every time you think about it just change the water. DO NOT PUT A PLASTIC BOTTLE ON THE STOVE OR IN THE OVEN)
15. Cut open your bottle and remove the soap. You should have a hard bar with very little water.
16. Test your soap. Cut off a piece the size of a raisin and put it into and empty bottle with about a cup of hot water and shake it. If you are successful, the bottle will fill with suds. A second test is to use a piece of litmus paper and dip it into the used bottle, it should NOT turn blue. If it turns blue you had too much NaOH or the soap isn't cured enough. If you fail either of these tests allow it to cure a few more days and try again. If it fails again, start over and be more careful this time. A pH of 8 or higher fails. Tape your piece of passing yellow or green pH paper into your notebook as evidence.
10 BONUS POINTS: Manufacturing glycerol. Glycerol is used for sweetener, moisturizer, pharmaceuticals, and the development of both explosives and plastics.
Make a concentrated bottle of soap suds by dissolving as much soap as possible into your test bottle.
Add table salt, NaCl: sodium chloride to this bottle. **TO CLAIM YOUR BONUS, YOU MUST EXPLAIN WHY THIS STEP IS IMPORTANT** The fatty acids will precipitate from solution and you can reclaim your soap by skimming it off the top. Bring in your glycerol in for testing.
2. Put your fat/oil into a beaker/saucepan
3. Heat your fat/oil until it melts(fat) or is warm to the touch(liquid oil)... continue the steps below while its heating.
4. Calculate how many grams of NaOH are needed to saponify the fat you have weighed out. Use unit factor analysis and table 19-1 above. SHOW YOUR WORK. No work = no credit. If you choose to blend different oils you need to do this for each oil/fat used. 5 point bonus for trying a mixture of oils.
5. Add up the total weights for your NaOH and multiply it by 0.95. This ensures that you don't have excess NaOH in your finished soap, it is far better to have your soap be a little extra greasy than to have your soap eat your skin away. Record this amount in your notebook, show your work.
6. Weigh out twice the amount of water as NaOH in a glass beaker. Record this in your notebook.
7. Stir the beaker of water and slowly add your NaOH, the solution should get hot as the ions form and release their bond energy.
8. Since oil and water don't mix... this next bit is tricky and requires specific temperatures. Allow both your fat/oil and your sodium hydroxide (NaOH) solution to cool to between 38 and 41 degrees Celcius (100-110 if you use Fahrenheit). NOT GETTING THIS RIGHT IS THE MOST COMMON REASON FOR FAILED SOAP. If you don't have a thermometer... you can judge them as about right when you can barely hold them in your bare hands without burning. This isn't recommended, but its possible.
9. Use a funnel to pour the fat into the 2L bottle.
10. Use the funnel to pour the sodium hydroxide solution into the 2L bottle.
11. Put the lid on the bottle and shake it until it looks like salad dressing.
12. If it starts to separate, shake it again, you want it to appear smooth and creamy.
13. When it no longer separates, let it sit for a few days. Depending on what you used, it could be ready in an hour or it could take several days to solidify.
14. Allow the soap to "cure" for a few days to harden (like poured concrete)... this will go faster if you keep the bottle warm. (best done by putting it into a pan of hot tap water ... every time you think about it just change the water. DO NOT PUT A PLASTIC BOTTLE ON THE STOVE OR IN THE OVEN)
15. Cut open your bottle and remove the soap. You should have a hard bar with very little water.
16. Test your soap. Cut off a piece the size of a raisin and put it into and empty bottle with about a cup of hot water and shake it. If you are successful, the bottle will fill with suds. A second test is to use a piece of litmus paper and dip it into the used bottle, it should NOT turn blue. If it turns blue you had too much NaOH or the soap isn't cured enough. If you fail either of these tests allow it to cure a few more days and try again. If it fails again, start over and be more careful this time. A pH of 8 or higher fails. Tape your piece of passing yellow or green pH paper into your notebook as evidence.
10 BONUS POINTS: Manufacturing glycerol. Glycerol is used for sweetener, moisturizer, pharmaceuticals, and the development of both explosives and plastics.
Make a concentrated bottle of soap suds by dissolving as much soap as possible into your test bottle.
Add table salt, NaCl: sodium chloride to this bottle. **TO CLAIM YOUR BONUS, YOU MUST EXPLAIN WHY THIS STEP IS IMPORTANT** The fatty acids will precipitate from solution and you can reclaim your soap by skimming it off the top. Bring in your glycerol in for testing.
Chase Elberson melting fat using the double boiler method.
Chase choose to make candles instead of soap, you can see his wicks in the jars on the stove. A word of caution, those paper towels are awful close to the heating element on the stove and should probably be further back. Definitely so if you have a gas stove instead of an electric one as pictured here. |