Cyclohexene in dropper bottles

Cyclohexene in dropper bottles: Standard rubber teats on dropper bottles are not compatible with cyclohexene.

Anyone know of a dropper-bottle type that would be compatible with cyclohexene?

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Publication Date: 03 February 2016
Asked By: claude
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cyclohexene in dropper bottles

Answer in brief


This is a good question and an issue that most schools would come across. Cyclohexene is only used for one or two practicals each year, such as when comparing saturated and unsaturated hydrocarbons. Organic chemicals in general require special consideration when they are being transferred from their original container.


The recommended method for dispensing a few drops of cyclohexene is to transfer a small amount into a glass beaker or jar, which is kept in an operating fumehood. For short-term use, either a glass pipette fitted with rubber teat or a LDPE disposable dropping pipette is perfectly adequate. It is not recommended to store the cyclohexene in dropping bottles that are plastic (e.g., StullTM type) or in glass bottles that have rubber-based teats or stoppers.


Cyclohexene degrades on exposure to air and light through peroxidation and polymerisation. Therefore, quantities of decanted cyclohexene should be treated as waste and may be stored as non-halogenated organic waste for collection by a licenced waste contractor.


An alternative, is to transfer a small amount into a small, labelled, amber glass bottle with a screw cap lid and then use a pipette to take directly from this small bottle, which is kept sealed until required. This will protect the cyclohexene from air and light, reduce the amount of chemical waste being generated, and also avoid contamination of the stock bottle.


Additional information


Trying to find information for cyclohexene is challenging. The Mykin rubber compatibility chart http://mykin.com/rubber-chemical-resistance-chart-2, indicates that cyclohexene is incompatible with many rubber-based products including neoprene, EPDM (ethylene propylene diene monomer) and SB (styrene butadiene). Fluoroplastics appear to be suitable for storing alkenes, although they might be quite expensive or difficult to source, and so therefore may not be practical for a school setting for a one-off application. Our sources indicate that there is insufficient data to determine the compatibility of silicone products with alkenes.


Information about incompatibilities with cyclohexane, another chemical commonly used alongside the cyclohexene, is reasonably easy to find and most of the standard dropper bottle materials are also unsuitable. These include: natural rubber, latex and polypropylene. Low-density polyethylene is a suitable product to use. This would indicate that the disposable dropping pipettes would be suitable to use for short-term use.


References


‘Chemical Compatability Charts’ CP Lab Safety website, https://www.calpaclab.com/chemical-compatibility-charts/ (Accessed 11 February 2016)


IPEX. 2009. Polypropylene Chemical Resistance Guide, IPEX, Canada https://www.google.com/url?q=http://www.ipexinc.com/Content/Products/Pro...


‘Fluoroplastic products’, Vitlab website, http://www.vitlab.com/en/products/knowledge/fluoroplastic-products/ (Updated: January 2018)


‘Rubber chemical resistance chart’, Mykin Inc website, http://mykin.com/rubber-chemical-resistance-chart-2 (Accessed 11 February 2016)


The Good Year Tire and Rubber Company. 2003. Goodyear Chemical Resistance Charts. Appendix–Chemical Charts, http://www.hosecon.com/pdf/engineering/common/goodyearchemchart.pdf

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