Friday, June 17, 2011

Molecular Chemistry and Saponification and Surfactants


The chemistry of cleaning!
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.


Etymology
The term surfactant is a blend of surface active agent. Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups (their tails) and hydrophilic groups (their heads). Therefore, a surfactant molecule contains both a water insoluble (or oil soluble component) and a water soluble component. Surfactant molecules will migrate to the water surface, where the insoluble hydrophobic group may extend out of the bulk water phase, either into the air or, if water is mixed with an oil, into the oil phase, while the water soluble head group remains in the water phase. This alignment and aggregation of surfactant molecules at the surface acts to alter the surface properties of water at the water/air or water/oil interface.
 

From: http://en.wikipedia.org/wiki/Surfactant


Quilt cleaning...........


Kay Lancaster responded to this question in an issue of Creative Machine's online newsletter.   I reproduce it here, with many thanks to its knowledgeable author.
 

...Orvus,a/k/a sodium lauryl sulfate or SLS (same as sodium dodecyl sulfate) is an anionic detergent, not a soap. (If it were a soap, it would be a pain in the posterior to use in hard water areas, forming grey, insoluble scum.)  Conservators use Orvus because it doesn't have the optical whiteners and brighteners and bleaches, etc., and rinses out fairly well most of the time, except in very hard water-- you need many, many more rinses in hard water areas. (Conservators typically use water purified by reverse osmosis or by deionization to get around the hardness problem.)
Because it lacks optical brighteners, bleaches, builders, etc., it's not going to foam the  way you think of most detergents foaming, and it's not going to give that "whiter than white" look you get from commercial laundry detergents, and things may start looking dingy after repeated use.  (Optical brighteners are compounds that absorb ultraviolet light and re-emit it in the blue wavelengths.  Absorbing UV and re-emitting the energy may be good for long term light stability).
Orvus also lacks "antiredeposition agents", which means compounds that keep the dirt that's now suspended in the wash water from re-depositing in the fabric.  You get around this with Orvus with multiple rinses... textile conservators may use 20 or more rinses.
Best pH for getting greasy dirt out of clothes is quite alkaline, about 10 or so, so you may have a tougher time getting greasy dirt out with straight SLS, which generally has a near-neutral pH.
There are some other potential gotchas to using it under some conditions: adding vinegar or other acid to rinse water (which you'd typically do with a soap, and might do with wool or silk) can force the water's pH down to the point where the SLS chemically bonds to the wool or silk fibers.  If you treat fabric like a textile conservator, you can then rinse in deionized water till the cows come home and rain falls up, and you're not going to get it out of the fabric again.
Fabric softeners (and some of the germicides like quaternary ammonium compounds) are cationic detergents; they will react with anionic detergents like SLS in a reaction called "reverse saponification," which leaves a greasy, waxy goo on the fibers that's difficult to remove without using high pH (very alkaline) conditions or solvents.  If you leave it in the fiber, the goo will attract more dirt quickly.

From: http://hartcottagequilts.com/quiltcare.htm

Equine Shampoo.............

 What is a surfactant? Why are surfactants used in cleaners?
A surfactant (surface active agent) is a molecule that, when added to a liquid (water) at low concentration, changes the properties of that liquid at a surface or interface. Surfactants are used in cleaners to: (Basically it makes water wetter). Basically when you take surfactants (some examples of which are corn, soy, palm kernel oil), which is what our chemistry is made from, then mix it with water, it makes water wetter, thereby letting it penetrate faster and deeper, but very gentle, into the coat of an animal. Surfactants, when combined with water, lift hydrocarbons or (FOPS=fats, oils proteins & sugars or as we know it=DIRT) to the surface and we use the water to rinse it away. Another analogy: If you imagine taking oil and pouring it into a glass, then adding water to that same glass it would separate and the oil would come to the top. We are doing just that; when we foam on our surfactants with water, they go to the surface and lift the dirt; we then use the water to rinse the dirt away.

What are Hydrocarbons?
They are the simplest organic compound molecules (FOPS- fats, oils, proteins and sugars) which is dirt. They only contain carbon and hydrogen.

pH-What does it mean?
There is much confusion in regard to pH. What is most important is the reserve potential of alkaline or acid pH not the number itself. Therefore, an alkaline number of 10 or even 11 with a low reserve number (measurement of potential to do work) will not harm anyone, or anything. An acid product made with a plant enzyme that has a pH 1.8 is as safe for human skin as say 2% boric acid is for eyes because the acid reserve number is very low. As stated on our Total Body Wash page we feel the USEPA (DfE) says it all. We know of no other product in the equine or animal industry that can make this statement. Always remember that between 3.0-10.0 are considered a neutral range of pH. Here are a few examples to better understand the scale of pH: As you can see it is very diverse. We hope these facts help you to have a better understanding. Battery Acid 1.5, Lemon Juice 2.5, Vinegar 2.8, Perrier Water 5.5, Milk 6.5, Baking Soda 8.5, Sea Water 9.0, Evamor Water 9.5, Milk of Magnesia 10.5, Liquid Drano 11.0, and Ammonia 12.5 Caution: The optimum pH for bacterial growth is 5.5 to 7.0 Beware of any cleaning solution that has this pH for cleaning.

From: http://www.ezall.com/products/tbw.html


More info here:  http://www.newton.dep.anl.gov/askasci/phy00/phy00627.htm

During the process a slow chemical splitting of the neutral fat took place; the fatty acids could then react with the alkali carbonates of the plant ash to form soap (this reaction is called saponification).

When making soap and detergent - a chemical compound; both cold and semiboiled methods are used:
In the semiboiled method, the fat is placed in the kettle and alkali solution is added while the mixture is stirred and heated but not boiled. The mass saponifies in the kettle and is poured from there into frames, where it solidifies. n the cold method, a fat and oil mixture, often containing a high percentage of coconut or palm-kernel oil, is mixed with the alkali solution. Slightly less alkali is used than theoretically required in order to leave a small amount of unsaponified fat or oil as a superfatting agent in the finished soap. The mass is mixed and agitated in an open pan until it begins to thicken. Then it is poured into frames and left there to saponify and solidify.  Because these methods are technically simple and because they require very little investment for machinery, they are ideal for small factories.

From:  http://www.britannica.com/EBchecked/topic/550751/soap-and-detergent/82274/Cold-and-semiboiled-methods?anchor=ref624636

SO, now you know!!  Fascinating!!


Picture from:  http://beeftallow.com/uses-of-beef-tallow_this-is-no-soap-stuff-5-bottlenecks-you-may-face-in-tallow-soap-making_79.html