Michelle A.

Chemistry

Possible Causes of the Fire

Introduction:

As the smoke cleared after the horrendous incident, the arsonist left clues of what he may have used to create such a large fire, an exothermic chemical reaction that can produce heat, light, and other products. In this specific factory, however, the fire of this magnitude could be a result of a few chemical reactions. The factory may have originated from the fabric section, now the real question is which fabric?

Fabric:

Cotton

Cotton is 99% cellulose, this macromolecule can become a polymer by an anhydroglucose unit chain.

CellobioseRepeatUnit

http://www.cottoninc.com/product/NonWovens/Nonwoven-Technical-Guide/Cotton-Morphology-And-Chemistry/

The cellulose chains within cotton fibers contain hydrogen bonding. These hydrogen bonds occur between the hydroxyl groups of adjacent molecules and are most abundant between the parallel, closely packed molecules in the crystalline areas of the fiber.

Because it is a natural fiber (meaning contains carbons) it is very flammable without a chemical treatment that allows the cotton to become less flammable.

Wool

Wool fiber is a protein called keratin, which is made up of amino-acids joined by peptide links.

keratin

http://itech.dickinson.edu/chemistry/?cat=69 (scroll for picture)

Wool does not have to be specially treated to become non-flammable due to its high nitrogen and water content.

Rayon

Rayon fiber is a semi-synthetic, cellulosic substance with similar properties of cotton.

rayon.png

http://www.realmenrealstyle.com/manmade-synthetic-fabrics-menswear/ (scroll for picture)

If the temperature is too high then the artificial cellulose will catch on fire.

Conclusion:

Out of the three main clothing fabrics, an individual can rule out the possibility of wool being the reactant of the fire. This leaves to natural and synthetic cellulose products. Cellulose is a flammable substance due to the composition of the material. Common materials made up of cellulose are wood and paper, both of which is very flammable. It also contains the elements carbon and oxygen, carbon of which is a substance needed to keep the fire burning and oxygen helps the fire keep going as well.

Here is what is to believed to be done:

The arsonist came in with lighter fluid (which is either alcohol or petroleum based, both being very flammable) and a match (which has red phosphorous, that is very reactive when friction occurs). He ventured to the cottons area and spread lighter fluid and struck the match than ran for it. However, as the fire burned, traces of carbon monoxide became prevalent. The following is an equation demonstrating the reaction:

C6H10O5 + 3O2 -> 6CO + 5H2O

There was about 1140.00 grams of cotton, but the amount of oxygen consumed by the fire was approximately 337.444 grams of oxygen (see below for calculation)

1140g C6H10O5 x 1mol C6H10O5/ 162.16g C6H10O5 x 3mol O2/1 mol C6H10O5 x 16.00g O2 = 337.444g O2

In a complete combustion reaction about twice as much oxygen is consumed by the fire (674.889g). The calculation is provided below.

1140g C6H10O5 x 1mol C6H10O5/ 162.16g C6H10O5 x 6mol O2/1 mol C6H10O5 x 16.00g O2 = 674.889g O2

This shows that there were insufficient amounts of oxygen present resulting in the toxic carbon monoxide. The amount of this poisonous gas is about 590.739 grams of carbon monoxide.

1140g C6H10O5 x 1mol C6H10O5/ 162.16g C6H10O5 x 6mol CO/1 mol C6H10O5 x 28.01 CO = 590.739g CO

Thankfully factory workers were able to escape before breathing in fatal doses of this terrible gas.

 

Bibliography:

“Cotton Morphology and Chemistry.” Cotton Inc. AMERICA’S COTTON PRODUCERS AND IMPORTERS, n.d. Web. 19 Mar. 2016.

RD, Sarah Pflugradt MS. “Is Cellulose Flammable?” EHow. Demand Media, n.d. Web. 02 Apr. 2016.

Sayed, Abu. “Rayon Fibre | Physical and Chemical Properties of Rayon Fibre – See More At: Http://textileapex.blogspot.com/2015/01/rayon-fibre-physical-chemical-properties.html#sthash.UJnEjd72.dpuf.” Textile Apex. Textile Apex., n.d. Web. 02 Apr. 2016.

Van Delden, Elisabeth. “Flame Resistance Tests.” Encyclopedic Dictionary of Polymers (n.d.): 412. International Wool Textile Organisation. IWTO. Web. 02 Apr. 2016. <http://www.iwto.org/uploaded/Fact_Sheets/Wool_and_Flame_Resistance_IWTO_Fact_Sheet.pdf&gt;.