1-OCTENE: CHARACTERISTICS, SYNTHESIS, USE, SAFETY SHEET - CHEMISTRY - 2024

The 1-octene is an alkene, organic chemical nature which is composed of a carbon chain of 8 arranged linearly (aliphatic hydrocarbon) with a double bond between the first and second carbon (alpha), denominating 1-octene.

The double bond makes it an unsaturated hydrocarbon. Its chemical formula is C ₈ H ₁₆ and its classical nomenclature is CH2 = CH-CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₃. It is a flammable compound that must be handled with care and requires to be stored in the dark, at room temperature and away from strong oxidants and water drains.

Graphic representation of the chemical structure of 1-octene. Source: Pixabay.com. Edited image.

The synthesis of this compound is carried out through various methodologies, among the most common is the oligomerization of ethylene and the Fischer-Tropsch synthesis. It should be noted that these procedures produce pollution to the environment.

That is why Ávila-Zárraga et al. Describe that alkenes can be synthesized through a methodology known as green chemistry, which does not generate residues that harm the environment.

They also ensure that by applying the clean or green chemistry methodology, a higher percentage of performance is obtained, since the study revealed a percentage of 7.3% for the traditional method and 65% for the green method.

It is used as a raw material for the synthesis of other organic compounds with important uses at the industry level. It also serves as a food additive (flavoring).

characteristics

The 1-octene is chemically defined as an alkene of 8 linear carbons, that is, it is an aliphatic hydrocarbon. It is also an unsaturated hydrocarbon due to the fact that it has a double bond in its structure.

It has a molecular mass of 112.24 g / mol, a density of 0.715 g / cm ³, a melting point of -107 ° C, a flash point of 8-10 ° C, an autoignition point of 256 ° C and a boiling point at 121 ° C. It is a colorless liquid, with a characteristic odor, insoluble in water and soluble in non-polar solvents.

The vapor given off by this product is heavier than air and the liquid is denser than water.

Synthesis

There are several methods for synthesizing 1-Octene, the oligomerization of ethylene and Fischer-Tropsch synthesis being among the best known methodologies.

Ethylene oligomerization

Ethylene oligomerization is mainly implemented by major companies, such as Shell and Chevron.

This technique uses homogeneous catalysts with transition metals (organometallic catalysts) together with cocatalysts such as aluminum alkyl.

However, due to its high cost and contamination to the environment, methodologies that use heterogeneous catalysts are being sought today to minimize costs and reduce environmental contamination.

Fischer-Tropsch synthesis

On the other hand, the Fischer-Tropsch synthesis is widely used by major companies, such as Sasol (a South African petrochemical oil and gas company).

Fischer-Tropsch technology is based on the transformation of gases (carbon monoxide and hydrogens) into liquid hydrocarbons.

This reaction requires the intervention of metallic catalysts and specific conditions of pressure and high temperature (150-300 ° C). This technique generates tons of sulfur dioxide (SO ₂), nitrogen oxides (NOx) and carbon dioxide (CO ₂) per day as waste into the environment (all pollutants).

However, one of the most recent and proposed methodologies to avoid polluting the environment is the dehydration of alcohols, using the tonsil SSP as a catalyst.

The SSP tonsil is composed of metal oxides, such as: (SiO ₂, 73%; Al ₂ O ₃, 9.1%; MgO, 2.9%; Na ₂ O, 1.1%; Fe ₂ O ₃, 2.7%; K ₂ O 1.0%; CaO 2.0% and TiO ₂ 0.4%). This technique is classified within the processes called green chemistry. This replaces sulfuric acid and / or phosphoric acid.

Synthesis by the traditional method

a) Have a direct reflux equipment which is essential to carry out the procedure.

Source: No machine-readable author provided. Ikertza assumed (based on copyright claims).. Edited image.

b) In a flask dispense 25 ml of 98% sulfuric acid or 85% phosphoric acid with 4 ml of octanol.

c) The solutions are mixed with the help of a grill with stirring and heating.

d) Over a period of 90 minutes heat under reflux.

e) Set up a fractional distillation equipment.

f) Raise the temperature moderately and collect the distillate in a suitable container (Erlenmeyer flask), it is cooled in an ice bath.

g) Remove from the heat source when a little liquid residue remains inside the flask, or when the emission of white vapors generated by the decomposition of the reaction mixture is observed.

h) Sodium chloride is used to saturate the distillate, then decant with the help of a separatory funnel.

i) Carry out 3 washes with 5 ml of 5% sodium bicarbonate each time.

j) Collect the organic phase in a flask and then place in an ice bath to cool.

k) Anhydrous sodium sulfate is then used for drying. Subsequently, the organic phase obtained is decanted, corresponding to alkene (octene).

l) The black liquid residue obtained is the product of the decomposition of organic matter, it must be treated with basic solutions to neutralize the pH.

Synthesis by the green method

a) Enable a direct ebb equipment.

b) In a flask, dispense 4.8 ml of octanol and 0.24 of the catalyst (tonsil SSP).

c) The solutions are mixed with the help of a grill with stirring and heating.

d) Over a period of 90 minutes heat under reflux.

e) Set up a fractional distillation equipment.

f) Raise the temperature moderately and collect the distillate in a suitable container (Erlenmeyer flask), it is cooled in an ice bath.

g) Remove from the heat source when a little liquid residue and the catalyst remain inside the flask.

h) Sodium sulfate is used to dry the distillate. Later decant with the help of a separatory funnel. The organic phase obtained corresponds to alkene (octene).

Source: Ávila-Zárraga G, Cano S, Gavilán-García I. Green chemistry, Obtaining alkenes applying the principles of green chemistry Educ. Chem, 2010; 21 (2), 183-189. Available at: scielo.org.

Use

The 1-octene behaves as a comonomer, that is, it is a monomer that polymerizes with other monomers different from it, even having the ability to polymerize with itself.

This is how this product is useful in the elaboration of other substances of an organic nature, such as high and low density polyethylene and surfactants.

On the other hand, it is an important compound in the chain of reactions necessary to obtain linear C9 aldehydes. These are subsequently transformed by oxidation and hydrogenation reactions into a fatty alcohol (1-nonanol), used as a plasticizer.

1-Octene is used as a flavoring agent and is therefore added to certain foods in the United States.

Safety sheet

1-Octene is a highly flammable substance, the mixture of its vapors with other substances can generate an explosion. As a preventive measure, the use of compressed air to handle this substance should be avoided. It should also be kept in an environment free from flames and sparks. In case of fire use dry powder, carbon dioxide or foam to extinguish flames.

The substance should be handled with a gown, gloves and safety glasses and under a fume hood.

Inhalation of the product produces drowsiness and vertigo. Direct contact causes dry skin. In case of contact with skin or mucous membranes, it is recommended to wash the affected area with plenty of water, in case of inhalation the patient should leave the area and breathe clean air. In case of ingestion in large quantities, seek medical advice and do not induce vomiting.

This product should be stored at room temperature, away from strong oxidants, protected from light and away from water drains.

In case of spillage, it should be collected with an absorbent material, for example sand. This product should not be disposed of in sewers, drains, or in any other way that affects the environment, as it is toxic to aquatic life.

References

1. Ávila-Zárraga G, Cano S, Gavilán-García I. Green chemistry, Obtaining alkenes applying the principles of green chemistry Educ. Chem, 2010; 21 (2), 183-189. Available at: scielo.org.
2. Wikipedia Contributors, '1-Octene', Wikipedia, The Free Encyclopedia, June 11, 2019, 22:43 UTC, Available at: org
3. Moussa S. Oligomerization of ethylene on heterogeneous ni-beta catalysts. Preliminary kinetic study. Institute of Chemical Technology. Polytechnic University of Valencia. Available at: /riunet.upv.es/
4. National Institute for Safety and Health at Work. Government of Spain. 1-Octene. Available at: ilo.org/
5. Joint FAO / WHO Food Standards Program Codex Committee on Food Additives. Proposals for additions and changes to the priority list of food additives proposed for evaluation by JECFA. 45th meeting Beijing, China, March 18-22, 2013.Available at: fao.org/