Corexit – 2-Butoxyethanol Studienprojekt DaMocles B.SPD SS 2013

Jessica Huppertz, Julian Ilgen, Marko Ilovaca und Viktor Klippenstein

1. Introduction

Corexit is a brand name of Nalco Holding Company for a line of . The substance came to be known due to its large scale use for disposal of oil related to the Deepwater Horizon in 2010. Since then the substance has become highly controversial, even banned in the UK. The substance is not a pure one but a mixture of different substances, which was for a long time a trade secret of Nalco Holding Company. The main components with approximate quantity are shown below from a safety data sheet of Nalco Holding Company.

Chart 1: Chemical composition of Corexit [1] Corexit EC9527A Corexit EC9500A Substance Amount Substa nce Amount 1,2 -Propan ediol 1 – 5 % 1,2 -Propan ediol 1 – 5 % org. sulfon ic acid salts a nd 10 – 30 % Org. sulfon ic acid salts and 10 – 30 % aliphatic acids of sorbitol ester aliphatic acids of sorbitol ester 2-Butoxyethanol 30 – 60 % Light hydro treated petro leu m 10 – 30 % distillates

Only after the massive usage of Corexit in the Gulf of Mexico further components of Corexit EC9527A and Corexit EC9500A have been published due the pressure by the EPA (Environmental Protection Agency). However, the exact chemical composition is still unknown. The chemical composition is shown chart 2.

Chart 2: A list of chemical composition published by the EPA of Corexit EC9527A and Corexit EC9500A [2] Substan ce CAS -numb er 1,2 -Propan ediol 57 -55 -6 2-Butoxyethanol 111 -76 -2 1,4 -bis(2 -ethylhexyl)sodiumsulfosuccinate 577 -11 -7 Sorbitan e monooleat e 1338 -43 -8 Polysorbat 80 9005 -65 -6 Polysorbat 85 9005 -70 -3 1-(2 -Butoxy -1-methylethoxy)propan -2-ol 29911 -28 -2 Light hydro treated petro leu m distillates 64742 -47 -8

In terms of chemical and toxicological characteristics the main component of Corexit EC9527A 2-butoxyethanol is being viewed in illustration 1 and 2 below.

Illustration 1: structural formula of 2-Butoxyethanol

Corexit | Studienprojekt DaMocles | Jessica Huppertz, Julian Ilgen, Marco Ilovaca, Viktor Klippenstein 2

Illustration 2: Ball-and-Stick Model of 2-Butoxyethanol

2. History

2.1. Product development of Corexit

In 1960, the first Corexit products were developed by an affiliated company of the Exxon oil company. After that, it got known for its regular use in various oil spills. In 1994, the Exxon Chemical Company merged with the specialized water treatment company Nalco Company and with it launched various Corexit products. However the subsidiary (Nalco / Exxon Energy Chemicals) completely passed into the possession of the Nalco Company for an equity acquisition in 2001. After the disaster of the Deepwater Horizon Nalco Company's the share price increased by 10% and the Nalco Company earned around 40 million U.S. dollars, since all stocks of Corexit have been bought by the BP Company. In May 2010 the EPA requested the BP to use a less toxic chemical to get rid of the oil spill.

2.2. Known Usage

In 1979 Corexit 9527 was applied to an area of 2800 km ² after the disaster at the oil rig Sedco 135F in the southern Gulf of Mexico. The operator PEMEX claimed that half of the spilled oil had been burned, evaporated or been dispersed with Corexit. 1989 Corexit 9527 was used on the shores in Alaska after the oil spill caused by the oil tanker from the company ExxonMobil. The most known case is the oil spill of the oil rig Deepwater Horizon on the 20.4.2010 in the Gulf of Mexico. In this case, about 7.57 million liters of Corexit 9500 and Corexit 9527 were distributed by either the use of aircraft or by ship into the ocean. The idea behind it was to cause the oil not to be washed up on the beach, but to be dispersed in the deep ocean Illustration 3: Distribution of Corexit on the Gulf of and therefore reduce the environmental Mexico by plane [2] damage. Several researchers have criticized the use of such a large amount of Corexit, since the Nalco Company held the exact composition a secret at this time and no one could know how much of an impact it would have on the environment. In addition to that, there were only a few toxicological studies of Corexit itself and its effect together with dispersed oil. Under the pressure of the EPA the

Corexit | Studienprojekt DaMocles | Jessica Huppertz, Julian Ilgen, Marco Ilovaca, Viktor Klippenstein 2

Nalco Company finally published a safety documentation of Corexit with all its compounds in June 2010.

3. Synthesis of 2-Butoxyethanol

2-butoxyethanol belongs to the class of alkylene glycol monoethers and is an important industrial chemical, wherefore 2-butoxyethanol is produced industrially. The general structure of this class of ethers is shown in Illustration 4.

Illustration 4: General structure of alkylene glycol monethers with R1 = H or Alkylene und R 2 = Alkylene

The most commonly used commercial synthesis occurs in two steps. It is based on the basic chemical ethylene. It is synthesized at a heterogeneous silver catalyst in a tube bundle reactor with molecular oxygen at a temperature of above 200 °C and a pressure of about 10 bar and delivers the intermediate ethylene oxid (Illustration 5).

Illustration 5: Synthesis of ethylene oxid In the second step the ethylene oxid reacts with n-butanol on a catalyst under ring opening to 2-Butoxyethanol. (Illustration 6).

Illustration 6: Reaction of ethylene oxid with n-butanol to 2-butoxyethanol

Under laboratory conditions, the ring opening is usually catalyzed by acidic or basic compounds, which does not come into question under large-scale conditions. Therefor the catalyst must to be removed, which would make it unusable for further use. In addition salt solutions are formed which must be disposed of. In the industry a variety of heterogeneous catalysts are used. Many are based on mixed oxides for example magnesium, aluminium and

Corexit | Studienprojekt DaMocles | Jessica Huppertz, Julian Ilgen, Marco Ilovaca, Viktor Klippenstein 3

vanadium or in case of BASF patents metal antimoniates and multi-metall cyanides. Important for these heterogeneous catalysts is the selectivity towards the alkylene glycol monoether because as by-products there can be formed alkylene glycol diether or polymers. An Alternative syntheses starts at the cyclic acetal, 2-propyl-1,3-dioxolane which is hydrogenated over finely dispersed palladium on aluminum oxide in the gas phase with molecular hydrogen (Illustration 7).

Illustration 7: Synthesis of 2-Butoxyethanol by catalytic hydrogenation of 2-Propyl-1,3-dioxolan

Using titanium-silicate molecular sieves, in a fixed bed reactor, the synthesis of 2- butoxyethanol is possible starting from ethylene and n-butanol with hydrogen peroxide in one step (Illustration 8).

Illustration 8: Direct synthesis of 2-Butoxyethanol on titanium-silicate molecular sieves

4. of 2-Butoxyethanol and Corexit

4.1. Effects of 2-Butoxyethanol

Contact with gaseous 2-butoxyethanol (2-BE) may cause irritation of eyes, nose, mouth, throat, and also cause headaches and nausea. In rats, 2-BE causes haemolysis, which increases the destruction of red blood cells and leads to death. In humans, this effect was observed only at a very high dose. In vitro it was shown that human blood cells are much less susceptible to 2-BE. Various animal studies have shown that 2-BE is damaging the kidneys, lungs, liver and spleen. It is known that 2-butoxyethanol may increase as a solubilizer between hydrophilic and lipophilic phases the toxicity of pollutants as a result of better absorption.

4.2. Metabolism

The absorption of 2-butoxyethanol is mainly through breathing and through the skin. Absorption through the skin is especially fast due to the particular solubility in many media. A mixture of 2-butoxyethanol in water increases dermal absorption. It could be proved that the workers who came in contact with 2-butoxyethanol have a significant amount of 2-Butoxy acetic acid in urine, which is present either in free form or bound to the amino acid glutamine. The excretion of the potentially dangerous material is preceded by an oxidation,

Corexit | Studienprojekt DaMocles | Jessica Huppertz, Julian Ilgen, Marco Ilovaca, Viktor Klippenstein 4

wherein it is assumed that the toxicity of 2-butoxyethanol lies in its metabolite. The metabolism is shown schematically in Illustration 9.

Illustration 9: Metabolism of 2-Butoxyethanol 4.3. Corexit

In the wake of the massive use of Corexit in the Gulf of Mexico after the explosion of the Deepwater Horizon, debates over a large number of toxicological studies was conducted in the process. Prior the toxicity of Corexit was largely unknown and the extent of pollution in the Gulf of Mexico is still unknown. The studies were performed on different laboratory animals such as crustaceans, fish, birds, rats, but also with consideration of different aspects, among other: lethal dose, enzyme activity, fertility, behavior changes, birth defects or developmental disorders. The results were very different, and therefore it was difficult to make a general statement about the toxicity of Corexit. One is however clear. The studies indicate that Corexit is highly toxic and increases the toxicity of oil through easier absorption for the aquatic organisms and even higher organisms

5. Source

− [1] Material Safety Data Sheet von Corexit 9500 und Corexit 9527 − [2] http://bpoilspillcrisisinthegulf.webs.com/corexit.htm − http://www.spiegel.de/wissenschaft/natur/us-oelkatastrophe-mit-gift-gegen-gift-a- 693566.html − OECD SIDS – 2-Butoxyethanol − A.W. Rettenmeier, R. Hennigs, R. Wodarz: Determination of butoxyacetic acid and N- butoxyacetyglutamine in urine of lacquerers exposed to 2-butoxyethanol − James Wise, John P. Wise, A review of the toxicity of chemical dispersants − GESTIS-Stoffdatenbank: 2-Butoxyethanol − Francois Malherbe et al, Catalysis Letters 67, 2000 , 197-202 − Devon, Thomas James and Billodeaux, Damon Ray , PCT Int. Appl. , WO 2012177591 A1 20121227 2012 − Quaschning et al, PCT Int. Appl. , WO 2005087696 A1 20050922 2005 − Wloka, Veronika; Triller, Michael, Ger. Offen. , DE 102008002091 A1 20081211 2008 − Song, Weiming; Deng, Qigang, Faming Zhuanli Shenqing , CN 102350371 A 20120215 2012

Corexit | Studienprojekt DaMocles | Jessica Huppertz, Julian Ilgen, Marco Ilovaca, Viktor Klippenstein 5