SHAWN FORTHSYTHE RE; double chen activity w/18* temp rise

[Dolly Llama]

Or any other chem gUrooz/brainiacs



Josh said,

"I was taught that once your rinse solution reaches 118 degrees, the chem activity doubles for each progressive 18 degree increase."

give us the skinny on that.

break it down for us non genius types.

tell us about cloud points and if they relate to that "double chem reactivity for ever 18 degrees"

and PLEEZE...'splain it in SIMPLE terms so i don't feel like I'm sitting in a Dr Aziz post graduate class.....
(if possible)

Thanks


..L.T.A.

 

[Shawn Forsythe]

It's an overused axiom, because it's so often misapplied.

While the the rule, called the "rule of Arrhenius", predicts a doubling of a chemical reaction rate upon every 10°(centigrade) increase in temperature, it does not follow that there would be a corresponding measured increase in the activity or process of cleaning.

This is mainly due to the fact that cleaning, as we know it, is principally a physical process, not a chemical reaction, per se. Yes, heat does aid cleaning, just not at any predictable increase as it relates to the increase in heat.

As well, the "Rule", is more of an observation as it pertains to a subset chemical chain reactions which are heat dependent. A few reactions are in fact not heat dependent, and are hardly effected by an increase in heat, while others can be accelerated exponentially by a slight increase in heat. So, the "rule" becomes a "rule of thumb", more than anything else.

However, heat is an excellent accelerator for physical processes too. As we add heat energy, we speed up molecular movement. Physical reactions are often aided by molecular movement to overcome forces of repulsion or boundary layering that keeps solvents from actively dissolving solutes, or in this case soils. Heat energy also aids surfactants in their ability to surround oil droplets, and heat combined with physical agitation helps form smaller oil droplet sizes for the surfactants to form surrounding structures, called "micelles". it is these surrounding structures, or micelles that permit surfactant(detergents) to "dissolve" and suspend oil into water to make it able to be flushed from the fibers with extraction or rinsing.

However, every surfactant has a limitation of the effective temperature, called its "cloud point". Simply put, the cloud point is the upper temperature extreme, that when reached, the surfactant's structure falls apart. The surfactant itself is no longer able to be dissolved in water, and it "clouds" the solution. As well, the surfactant is unable to form micelles to surround fat/oil droplets, and the process of detergency is abated. In most cases, returning the solution to below the cloud point restores the activity. It's not as though overheating a surfactant a little in the heater, or in the solution line destroys anything, so long as it remains dispersed and cooled below the cloud point as it is applied to the surface being cleaned.

 

[Ernie G]

Well Larry, you got your simple answer, I think!

 

[Shawn Forsythe]

The short answer is highly technical, while the simplistic explanation is lengthy and wordy. I tried to strike a middle-ground. :?

Suffice it to say that the 18 degree rule of doubling increase in reaction is not very applicable to our typical cleaning process, while at the same time heat itself does aid cleaning immensely for other reasons.

The rule however is much more applicable to stain removal processes that DO involve a chemical reaction, such as the addition of a reducing agent or oxidizing agent to stains that will be effected by the procedure. Hence, we add heat to Red Relief to accelerate the process. Sometimes we want an increase, just not the doubling every 18 degrees, such as with Stain Magic, for which the acceleration causes uncontrolled bleaching of dyes.

 

[Dolly Llama]

Well Larry, you got your simple answer, I think!

Indeed we did , Ernie
a damn fine job Shawn did in explaining it.

i really appreciate Shawn's knowledge and input.
However, sometimes i think his over large brain forgets that most of us here are mere mortals.
( he needs to reminded at times)

We only get to see the inside of the Mensa club house when cleaning the carpets or scrubbing the toilets....


seriously, thanks Shawn

..L.T.A.

 

[CleanEvo]

What did he say?

 

[Askal]

That Shawn is so smart. Or if your aux. heater quit you would see the short answer.
Al
al

 

[Hoody]

Shawn,

Is the cloud point, the same as boiling point as referenced on a MSDS sheet ?

What products tend to have a lower temp cloud point, or reach that point sooner ? Alkali, acids ? Those containing sodium, phosphates, ethanol ?

 

[Blue Monarch]

Is that why my QD at the machine always gets caked up when I use clean-it? A couple of uses and it's so bad flow is restricted.

Never could figure out what's going on there. All the QD's down the line are fine.

 

[Shawn Forsythe]

Shawn,

Is the cloud point, the same as boiling point as referenced on a MSDS sheet ?

What products tend to have a lower temp cloud point, or reach that point sooner ? Alkali, acids ? Those containing sodium, phosphates, ethanol ?

The Cloud Point has no relationship with the boiling point that I am aware of. The Cloud Point is a characteristic of surfactant. Every surfactant used for detergency has a set cloudpoint which is not changed by the nature of the balance of the end formulation. The surfactant performs at its best at just under the cloud point temperature level. As this is the case, a formulation that is designed for high-heat (high cloud point surfactants), may not perform at peak efficiency at low heat levels. Conversely, a cold water detergent (low cloud point) ceases to function in high heat situations.

A formulator deals with this in a few different ways. He can indicate the desired operating range for the product, he can blend surfactants of differing cloud points, he can rely less on detergency with other formula components. There are advantages and disadvantages for any one of these choices. As well, cloud point alone is not the reason why a formulator might choose a particular surfactant(s). This is partially the great art of cleaning formulations. Choosing the right surfactants, their proportions, and the levels within a formulation is what partially dictates whether your product will excel in the marketplace. It's also a reason why formulations used for presprays differ from each other, and in-tank cleaners.

As to your other question, ... Cloud Point is not something you would even see put on an MSDS for the surfactant, let alone the MSDS for a formulation that may or may not have a blend.

 

[Hoody]

Thanks Shawn.