Chemical Forums

Chemistry Forums for Students => High School Chemistry Forum => Topic started by: yangyangg on May 15, 2006, 08:52:04 AM

Title: Detergents
Post by: yangyangg on May 15, 2006, 08:52:04 AM
Some people say that deterfents can react with grease to form soluble products so that the grease can be removed, is it correct?
Title: Re: Detergents
Post by: Yggdrasil on May 15, 2006, 01:51:18 PM
Detergents have nonpolar tail group and a polar head group.  In solution, the nonpolar tail groups are excluded from water, so they form micelles (http://en.wikipedia.org/wiki/Micelle) (the picture here is helpful).  In these micelles, the nonpolar tails form a hydrophobic environment in the interior, while the polar head groups create a polar environment on the outside.  Since the outside is polar, the micelle is able to disolve in water.  However, because the inside of the micelle is nonpolar, it can capture nonpolar substances (such as dirt and grease) which are soluble in a hydrophobic environment.  When these grease molecules become trapped in the micelles, they can be washed away with the water soluble micelles.

So, it really isn't a chemical reaction which solublizes the grease.  Basically the detergent micelles capture grease and allow them to enter the soluble phase and be washed away.
Title: Re: Detergents
Post by: mrdeadman on May 15, 2006, 07:37:10 PM
Detergents have nonpolar tail group and a polar head group.  In solution, the nonpolar tail groups are excluded from water, so they form micelles (http://en.wikipedia.org/wiki/Micelle) (the picture here is helpful).  In these micelles, the nonpolar tails form a hydrophobic environment in the interior, while the polar head groups create a polar environment on the outside.  Since the outside is polar, the micelle is able to disolve in water.  However, because the inside of the micelle is nonpolar, it can capture nonpolar substances (such as dirt and grease) which are soluble in a hydrophobic environment.  When these grease molecules become trapped in the micelles, they can be washed away with the water soluble micelles.

So, it really isn't a chemical reaction which solublizes the grease.  Basically the detergent micelles capture grease and allow them to enter the soluble phase and be washed away.
that's why it cleans up grease, grease and oil are nonpolar so they "stick" to the nonpolar side while water "sticks" to the polar side.  :o I remember we did an entire lab on this in the general chem.
Title: Re: Detergents
Post by: rctrackstar2007 on May 15, 2006, 07:48:42 PM
does anyone know any of the characteristics of Lava that make it such a good grease remover?
Title: Re: Detergents
Post by: Donaldson Tan on May 16, 2006, 07:16:33 PM
Lava = molten earth. LOL
Title: Re: Detergents
Post by: rctrackstar2007 on May 16, 2006, 07:18:29 PM
Lava = molten earth. LOL

no i mean the soap Lava, unless that was a hint of sarcasm in the intraweb air  ::)
Title: Re: Detergents
Post by: mrdeadman on May 16, 2006, 08:13:10 PM
im pretty sure that was sarcasm man.  :P
Title: Re: Detergents
Post by: rctrackstar2007 on May 16, 2006, 08:24:19 PM
im pretty sure that was sarcasm man.  :P

that's why included my little end note lol i was just to lazy to delete the first part