Monday, July 6, 2009

electron transfer at one distance

hehehe...
sekadar merehatkan minda..
video

seronok je tgk movementnye...

Saturday, July 4, 2009

Saponification

Soap making Oils and their Characteristics
(credit to http://www.colebrothers.com/soap/oils.html)

Klik http://www.youtube.com/watch?v=ta9h9S1JoI8


Terms:

Saturated Fat - Oils that make a hard soap. Usually come in a solid form and need to be melted before using. Coconut, cocoa butter, Palm oil are examples.

Scenting Oils - There are two types of scenting oils, fragrance oils, which are man-made and contain alcohol and essential oils which are natural. The alcohol in fragrance oils tends to cause problems in soap making so essential oil's are normally used in soap making. Essential Oil's are more costly and harder to find than Fragrance Oil's but have better scent retention and will not ruin a batch of soap. The only time fragrance oils can often be used safely is at the trace stage or during rebatching. Essential oils can be added at trace or in the base oil.

Superfatting Soap - This means that oils or fats have been left in the soap unconverted by the lye either because the amount of lye was decreased to allow some fat/oil to remain or oil/fat was added at the trace stage after the mix had saponified. (In lay terms saponification means that the lye/water and oils have been mixed and brought to a trace stage where at this point the lye has been mostly neutralized. Any oil added at this stage will basically remain unchanged in the final soap bar) The method of adding additional fat to the soap mixture after it has saponified had an advantage in that it allows the soap maker to better control what oil is left in the soap. Adding the extra oil at this time keeps it in its natural state, and ready to instantly moisturize your skin as you use the soap. When superfatting your soap at the trace stage make sure you use the 1% excess fat lye amount. Otherwise the soap will be too oily because it will not only contain the oil you add at the trace stage but will also have excess fat from a lack of lye.

Superfatting soap by decreasing the lye content eliminates the step of adding oil at trace but decreases the control that the soap maker has over what oil is left in the soap. For example, if 5% cocoa butter was added as part of the base oil (say 95% Olive Oil) and the lye amount was calculated for a 5% excess fat level the excess fat in the soap would be made up of a combination of Olive oil and cocoa butter with most of the excess fat being Olive oil. If the same batch was mixed using just Olive Oil at a 1% excess fat level and the cocoa butter was added at the trace stage you would know that the final soap bar contained 1% olive oil and 5% cocoa butter. The cocoa butter would have in this case been unaffected by the lye since it was added after the soap had traced.

(NOTE - When adding oils at the trace stage (superfatting) be sure to use a lye calculatation that gives you about 1% excess fat. When using our Soap-Calc program or any other lye calculator do not include the oils that you will be adding at trace in the calculation)

Trace - The point at which the soap/lye mixture begins to thicken. At this point the solution is about 80-90% saponified and essential oils, superfatting oils, colors, additives, etc can be added without their characteristics being changed substantially by the saponification process.

Unsaturated Fat - Oils that are in a liquid form. They need to be mixed with saturated fats at the base oil stage in order to create a hard bar.

Soap making Oils:

Sweet Almond Oil
Sweet Almond Oil is often used for superfatting soaps. It is a great moisturizer, makes a stable lather and helps condition the skin. Add 1 ounce per pound of fats to your soap batch at trace.

Aloe Vera Liquid, Aloe Vera Gel

Aloe vera is used in creams and lotions. It's a well known healing and soothing agent for damaged, dry skin. It is soothing and healing for burns, skin irritations, and raw open wounds. Liquid aloe vera may be added to cosmetic formulations, soaps, and straight on the skin.

Apricot Kernel Oil
Apricot kernel oil is often used for superfatting. It is also a good moisturizer and helps condition the skin. Use one or two ounces in every pound of fat at trace.

Avocado Oil

Avocado oil is a great moisturizer and is often used for superfatting soaps. Avocado oil contains vitamins A, D, and E, which makes it healing as well as moisturizing. Try it in a gentle baby soap. Use up to 30% as base oil.

Beeswax
Beeswax has the sweet smell of honey. Beeswax makes a harder bar of soap and is also used in creams, lotions, lip balms and candle making. It contains a high percentage of unsaponifiables. At best, half of these substances participate in the normal soap making reaction. You can use it at about 1 oz per lb. of oils in your base oils to make your soaps harder.

Calendula Oil

Has many therapeutic benefits and is known to successfully heal a variety of types of skin damage. (burns,wounds,dry skin) To superfat soap use 1 2/3 tablespoons per 5 lbs of soap at trace or use up to 20% added to other oils at the beginning of the soap making process.

Canola Oil
Canola oil is a good moisturizer but is less saturated than other fats, so it can be slow to saponify. Use it in place of more expensive oils like olive. Needs to be mixed with other saturated fats in order to speed up saponification. Use as a base oil up to 50%.

Castor Oil
Castor oil is often used to superfat. It attracts and holds moisture in the skin. Use it in combination with other vegetable oils to produce a nice hard bar of soap. You can add a bit at trace for superfatting or add it to other oils at a rate of no more than 30% in the beginning of the soapmaking process.

Cocoa Butter
Cocoa butter is used to make soaps harder. When used in soap as a superfatting oil it acts to lay down a protective layer which holds the moisture to the skin, so it is an excellent skin softener. It has a natural chocolate scent but it is also available in unscented versions. You can use it from anywhere about 1 ounce to a pound at trace, to 15% of your total base oils, depending on your preference.

Coconut Oil

Coconut oil makes soaps lather beautifully but can be drying when it makes up a large portion of your soap's fats. It will make a very hard, white bar of soap with abundant lather. It even lathers in very hard water or even sea water). Coconut oil is a saturated fat. Use it at a percentage of no more than 20-30% in your base oils.

Cottonseed Oil
Cottonseed oil produces thick and lasting lather, in addition to having emollient properties. It can be vulnerable to spoilage depending on the season, so use less of this oil. Maximum recommended usage - 25% of total base oils.

Emu Oil
Emu Oil is reported to help heal skin tissues and help draw other ingredients (like mint) down into your skin so they are more effective. Use 1 ounce per pound at trace.

Evening Primrose Oil

Evening primrose oil is absorbed quickly into skin and provides essential fatty acids that are reported to help inhibit bacterial growth and encourage antibodies so the skin is better able to defend against infection or inflammation. It is not recommended as an additive in soaps made for oily complexions. Recommended Usage - 2 tablespoons per 5 pounds of soap, added at trace.

Grapeseed Oil
Grapeseed oil is a lightweight oil that absorbs into the skin quickly without leaving a heavy greasy feeling. Used in soaps as a superfatting oil. Use one ounce per pound at trace.

Hazelnut Oil
Hazelnut is an excellent moisturizer for soaps. It is low in saturated fatty acids, so use other more saturated fats to lessen your trace time and yield a harder bar. Recommended maximum usage - 20% of total oils.

Hempseed Oil

Hempseed oil is not as stable as some other oils and can spoil quickly. It creates a silky bar of soap even if it is only used to superfat your batch. It is a less saturated fat, and since it is prone to spoilage, keep it as a small percentage of your mix to avoid having a soft, squishy soap that may spoil in a few months. Usage - As a Superfatting at 5% at trace or Base oil at 20-30% but no more than 40%.

Honey - (not an oil but can be used as an additive)

Honey is also a humectant, so it helps retain moisture on the skin in much the same way as glycerin. Use it at about 2 Tablespoons per pound of oils, added at trace.

Jojoba
Jojoba helps to promote a stable lather and is good at conditioning skin. Because of its expense, it's usually used to superfat soap batches or in shampoo bars. It is an excellent emollient for skin conditions like psoriasis, because it has a chemical composition very close to the skin's own sebum. It is suitable for all skin types, beneficial for spotty and acne conditions, and good for sensitive and oily skin. It also helps to unclog the pores and remove any embedded grime, restores and conditions hair. When using Jojoba in soap, limit its usage to one or two ounces per pound at trace. Jojoba naturally accelerates tracing in soap recipes. Used as a Superfatting oil.

Kukui Nut Oil
The kukui nut is native to Hawaii and is high in linoleic acid. It is quickly absorbed into the skin. Excellent for skin conditioning after sun exposure, as well as for acne, eczema, and psoriasis. It offers just the right amount of lubrication without leaving a greasy feeling. For soap making, use 2 tablespoons added to 5 lbs of soap at trace just before incorporating the essential oils to add richness to the soap. A higher percentage, 10-20% of the total fats also makes an outstanding soap.

Lard
Lard is made from pig fat much like bacon fat. Its advantages are that it is cheap, easily obtainable, and makes a nice lathery, white bar of soap. This fat should be combined with vegetable oils such as coconut or palm to compensate for the lard's shortcomings Without other oils it can tend to be soft and not work very well in cold water. Use it as a base oil. Recommended at 70% max of total oils.

Macadamia Oil
Macadamia is a luxurious and slightly expensive oil. It has a long shelf life so it can be purchased in quantity for a good price. It is a wonderful addition to any soap. It is easily absorbed into the skin and acts as an emollient protecting skin cells from deterioration and thus leading to better condition for your skin. Use for superfatting your soap. Use 1 ounce per pound at trace.

Mango Butter

Mango butter is extracted from the mango fruit. It is a yellowish oil and has almost no scent. It is a great moisturizer and should be used to superfat batches. Can be used at up to 15% of base or as a superfatting agent at 5% at trace.

Monoi Oil, also known as Monoi de Tahiti
Monoi oil is expensive but luxurious product made from coconut oil. It oil has wonderful moisturizing properties and is great for your skin. Use it as a base oil at 60% or higher.

Neem Oil
Extracted from the bark of the Neem Tree. This oil has the ability to treat a variety of skin disorders such as dandruff. Use as a base oil up to 40%.

Olive Oil
Olive oil is excellent as a base oil in soaps, either in whole (Castile soap) or in part. Avoid extra virgin olive oil. It is great for cooking but not for soap making. The lower the grade the better. Olive Oil prevents the loss of your skin's natural moisture, softens skin and attracts external moisture to your skin. It helps keeps your skin soft, supple and younger looking. If you're making an especially mild soap use Olive oil. Use as a base oil up to 100%

Palm Oil, also known as Vegetable Tallow

Palm oil makes a hard bar that cleans well and is also mild. It is a good substitute for tallow in all-vegetable soaps. The quality of Palm oil is far superior to other vegetable oils that are filler oils. Palm oil is universal and used in many expensive luxury soaps. Use is as a Base oil at 20 - 30%.

Palm Kernel Oil

Like Palm Oil, Palm Kernel oil makes a soap that is very hard and lathers well. It has most of the same qualities as palm oil. Use it as a Base oil at 20-30%

Peanut Oil
Peanut oil contributes long-lasting lather to a soap. It is highly unsaturated though, so it is prone to spoilage. Avoid using more than 20%. Peanut oil is similar to olive and castor oils and has a good amount of vitamin E. Use is as a base oil up to a 20% maximum.

Safflower Oil
Safflower oil is an unsaturated oil and should be used in combination with palm, coconut, or a similar oil. It is valuable for its moisturizing properties.
Use it as Base oil up to 60%. 20% of total is more highly recommended.

Sesame Seed Oil
Sesame oil is said to be good for Psoriasis, Eczema, Rheumatism, and Arthritis. It makes a good superfatting oil due to its moisturizing ability. It has a strong nutty scent. It makes a softish bar unless used in conjunction with other, more saturated oils. Use it as a 10% addition to base oils.

Shea Butter

Shea butter is a wonderful superfatting agent and contains a large percentage of ingredients that do not react with the lye thus remaining in the soap to nourish your skin. Use it with your base at up to 20% of your total oils or as a superfatting agent at 1 2/3 tablespoons per 5 pounds of oils added at trace.

Vegetable Shortening or Soybean
Oil
Vegetable shortening is normally made out of soybean oil. It is cheap and readily available and produces a mild, stable lather. Use it in combination with other exotic or moisturizing oils. Use this as half of your fats to keep costs down. It is a good filler and makes a very hard white bar when used alone and when mixed with other oils it makes a wonderful hard bar of soap. Use vegetable shortening as a base oil or combine it with other, harder oils for better results. Recommend use as base up to 50% of total oils.

Sunflower Oil

Sunflower oil is a less expensive alternative to olive oil. It contains Vitamin E, so it naturally resists going rancid (Vitamin E is a preservative). Despite that, don't store it longer than six months. It is a less saturated oil so you want to combine it with other, more saturated, oils -- try to avoid using more than about 15-20% sunflower oil. It can make your soaps take longer to trace and to harden. Use as a Base oil up to 20%

Wheat Germ Oil
This oil is thick, sticky and antioxidant. It's also very rich in vitamin E. Can be used to nourish dry or cracked skin and soothes skin problems such as eczema and psoriasis. Helps to prevent and reduce scarring and may prevent stretch marks. Mature skin, in particular, will benefit from wheat germ oil. Some people use it as a preservative in vegetable oils, soaps and toiletries, and others totally disagree as to its preservative powers. On its own, wheat germ oil oxidizes rapidly. It should be kept refrigerated. Use at 1 ounce per pound added at trace.

Tuesday, March 24, 2009

Redox

Redox

REDOX

(credit to http://www.shodor.org/unchem/advanced/redox/index.html)

Redox reactions, or oxidation-reduction reactions, have a number of similarities to acid-base reactions. Fundamentally, redox reactions are a family of reactions that are concerned with the transfer of electrons between species. Like acid-base reactions, redox reactions are a matched set -- you don't have an oxidation reaction without a reduction reaction happening at the same time. Oxidation refers to the loss of electrons, while reduction refers to the gain of electrons. Each reaction by itself is called a "half-reaction", simply because we need two (2) half-reactions to form a whole reaction. In notating redox reactions, chemists typically write out the electrons explicitly:

Cu (s) ----> Cu2+ + 2 e-

This half-reaction says that we have solid copper (with no charge) being oxidized (losing electrons) to form a copper ion with a plus 2 charge. Notice that, like the stoichiometry notation, we have a "balance" between both sides of the reaction. We have one (1) copper atom on both sides, and the charges balance as well. The symbol "e-" represents a free electron with a negative charge that can now go out and reduce some other species, such as in the half-reaction:

2 Ag+ (aq) + 2 e- ------> 2 Ag (s)

Here, two silver ions (silver with a positive charge) are being reduced through the addition of two (2) electrons to form solid silver. The abbreviations "aq" and "s" mean aqueous and solid, respectively. We can now combine the two (2) half-reactions to form a redox equation:

We can also discuss the individual components of these reactions as follows. If a chemical causes another substance to be oxidized, we call it the oxidizing agent. In the equation above, Ag+ is the oxidizing agent, because it causes Cu(s) to lose electrons. Oxidants get reduced in the process by a reducing agent. Cu(s) is, naturally, the reducing agent in this case, as it causes Ag+ to gain electrons.

As a summary, here are the steps to follow to balance a redox equation in acidic medium (add the starred step in a basic medium):

1. Divide the equation into an oxidation half-reaction and a reduction half-reaction
2. Balance these
* Balance the elements other than H and O
* Balance the O by adding H2O
* Balance the H by adding H+
* Balance the charge by adding e-
3. Multiply each half-reaction by an integer such that the number of e- lost in one equals the number gained in the other
4. Combine the half-reactions and cancel
5. **Add OH- to each side until all H+ is gone and then cancel again**

In considering redox reactions, you must have some sense of the oxidation number (ON) of the compound. The oxidation number is defined as the effective charge on an atom in a compound, calculated according to a prescribed set of rules. An increase in oxidation number corresponds to oxidation, and a decrease to reduction. The oxidation number of a compound has some analogy to the pH and pK measurements found in acids and bases -- the oxidation number suggests the strength or tendency of the compound to be oxidized or reduced, to serve as an oxidizing agent or reducing agent. The rules are shown below. Go through them in the order given until you have an oxidation number assigned.

1. For atoms in their elemental form, the oxidation number is 0
2. For ions, the oxidation number is equal to their charge
3. For single hydrogen, the number is usually +1 but in some cases it is -1
4. For oxygen, the number is usually -2
5. The sum of the oxidation number (ONs) of all the atoms in the molecule or ion is equal to its total charge.

As a side note, the term "oxidation", with its obvious root from the word "oxygen", assumes that oxygen has an oxidation number of -2. Using this as a benchmark, oxidation numbers were assigned to all other elements. For example, if we look at H2O, and assign the value of -2 to the oxygen atom, the hydrogens must each have an oxidation number of +1 by default, since water is a neutral molecule. As an example, what is the oxidation number of sulfur in sulfur dioxide (SO2)? Given that each oxygen atom has a -2 charge, and knowing that the molecule is neutral, the oxidation number for sulfur must be +4. What about for a sulfate ion (SO4 with a total charge of -2)? Again, the charge of all the oxygen atoms is 4 x -2 = -8. Sulfur must then have an oxidation number of +6, since +6 + (-8) = -2, the total charge on the ion. Since the sulfur in sulfate has a higher oxidation number than in sulfur dioxide, it is said to be more highly oxidized.

Working with redox reactions is fundamentally a bookkeeping issue. You need to be able to account for all of the electrons as they transfer from one species to another. There are a number of rules and tricks for balancing redox reactions, but basically they all boil down to dealing with each of the two half-reactions individually. Consider for example the reaction of aluminum metal to form alumina (Al2O3). The unbalanced reaction is as follows:

Looking at each half reaction separately:

This reaction shows aluminum metal being oxidized to form an aluminum ion with a +3 charge. The half-reaction below shows oxygen being reduced to form two (2) oxygen ions, each with a charge of -2.

If we combine those two (2) half-reactions, we must make the number of electrons equal on both sides. The number 12 is a common multiple of three (3) and four (4), so we multiply the aluminum reaction by four (4) and the oxygen reaction by three (3) to get 12 electrons on both sides. Now, simply combine the reactions. Notice that we have 12 electrons on both sides, which cancel out. The final step is to combine the aluminum and oxygen ions on the right side using a cross multiply technique:

Taking care of the number of atoms, you should end up with:


More REDOX info on http://www.chemguide.co.uk/inorganic/redox/definitions.html