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| Names | |
|---|---|
| IUPAC name
2-bromoacetyl bromide
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| Systematic IUPAC name
Bromoacetyl bromide | |
| Other names
Acetyl bromide
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| Identifiers | |
3D model (JSmol)
|
|
| 605440 | |
| ChemSpider | |
| EC Number |
|
| 605440 | |
PubChem CID
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|
| |
| |
| Properties | |
| C2H2Br2O | |
| Molar mass | 201.845 g/mole |
| Appearance | dark brown-yellow liquid |
| Density | 2.312 g/cm3 |
| Melting point | Not available |
| Boiling point | 148.5°C |
| log P | 1.32 |
| Vapor pressure | 3.8 mm Hg |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
|
corrosive, burns skin and eyes |
| Flash point | 105°C |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Bromoacetyl bromide is an organic compound with formula C2H2Br2O. It is a polar compound and is very reactive with water, bases, oxidizing agents, and alcohols. It can cause skin and eye burns, nose and throat soreness, and breathing problems. It is mainly used in the manufacturing of other chemicals such as dyes and pharmaceuticals.
Uses
editBromoacetyl bromide has several uses that include the synthesis of agrochemicals, pharmaceuticals, dyes, and other fine chemicals. An organic synthesis process involving bromoacetyl bromide is acetylation, in which the acetyl group is incorporated into a molecule[1]. Bromoacetyl bromide is also used in selective reactions for the cleavage of ethers and acetals. The bromine atom is a substituent in these reactions. If positioned correctly, the ether and acetal starting materials with these bromo substituents can then be used to extend the carbon chain [2]. Bromoacetyl bromide has also been useful for cationization of cotton. This compound was reacted with cellulose followed by substitution of the terminal bromine with triethylamine. This process increases the dye uptake of cotton fabric, making it more valuable commercially because of the better quality and time efficiency [3].
Properties
editBromoacetyl bromide is a compound with a molecular formula C2H2Br2O and a molecular weight of 201.845 g/mole. Another common name for this compound is acetyl bromide. Bromoacetyl bromide is a polar compound due to the electronegativity of the bromines in the structure. These electronegative elements pull electron density away from the carbons making them have a partial positive charge. The carbonyl group also pulls electron density away from the carbon because oxygen is the second most electronegative element. This makes the carbon very electrophilic and reactive. Polarity increases the boiling point and solubility of a compound. The boiling point of bromoacetyl bromide is 148.5°C, which is higher than water due to the strong polar bonds. Bromoacetyl bromide is very reactive with water. This is partially due to the electrophilic carbon and the oxygen in water having a lone pair of electrons to donate. There is no known melting point most likely due to the fact that at room temperature, 25°C, bromoacetyl bromide is a liquid. The density of bromoacetyl bromide is 2.312 g/cm3, which is greater than the density of water, 1.000 g/cm3. If this compound were to be added to a beaker of water it would float to the bottom and there would be a visible separation between the two layers. This would be the way to distinguish an organic layer from an aqueous one if bromoacetyl bromide were used in a reaction. [4] [5] .
Stability
editThe orbital hybridisation of the atoms in bromoacetyl bromide have a great effect on the stability and reactivity of the compound. The carbon attached to the bromine and oxygen is sp2 hybridized, creating 120o angles between the bonds and indicating that there is a double bond. The double bond consists of a single sigma bond and a pi bond on the carbon contains an extra pair of electrons that is reactive. However, because of the very electronegative elements surrounding the carbon, electron density is pulled away from the carbon, creating a partial positive charge. The sp2 hybridization also creates a strain on the carbon because it is not sp3 hybridized, which is the most stable hybridization. This causes the compound to be reactive with anything that will react with the electrons in the doulbe bond or donate electrons to the partial positively charged carbon. Bromoacetyl bromide is a relatively stable molecule under standard conditions; however, it reacts violently with water. The electron pairs on the oxygen atom in water react with the partial positive carbon in the stucture. Bromoacetyl bromide is not only incompatible with water and moisture, but also alcohols, strong oxidizing agents, and strong bases [6] . If not used, bromoacetyl bromide decomposes to carbon monoxide, hydrogen bromide, and carbon dioxide [7].
Hazard & Safety
editBromoacetyl bromide reacts violently with water and is moisture sensitive, so it should be kept in a dry, sealed unbreakable container when transported [8]. It should also not be transported with other flammable, combustible, or explosive chemicals. Bromoacetyl bromide is a corrosive chemical that can cause irritation and burning of the skin and eyes with the possibility of permanent eye damage. If inhaled, bromoacetyl bromide can cause soreness in the throat and nose along with irritation in the lungs, causing a cough or shortness of breath. Long-term exposure to bromoacetyl bromide at high concentrations can cause build-up of fluid in the lungs making it difficult to breath. Smoking can worsen respiratory problems caused by bromoacetyl bromide. If exposed to bromoacetyl bromide, seek medical attention immediately. Chest x-rays are important in making sure the lungs have no fluid and are functioning properly. The most effective method for limiting exposure during a process is using proper engineering controls, such as flow rate sensors, pressure gauges, thermometers, safety pressure valves and shutting off valves. It is also important to wear proper equipment, such as goggles, gloves, coveralls and respirators. There should also always be proper ventilation provided at the transfer and handling sites [9].Bromoacetyl bromide has been cited by the Department of Transportation and is now on the Hazardous Substance List along with the Special Health Hazard Substance List. In the Emergency Response Guide Book, the identification number for bromoacetyl bromide is 2513 and guide number is 156 [10]. Bromoacetyl bromide does have the potential to combust, but does not readily ignite. If bromoacetyl bromide reacts with water, it may form a toxic flammable gas. This gas may then ignite if in contact with steam or moisture. Bromoacetyl bromide also decomposes to form hydrogen bromide, which is toxic. In case bromoacetyl bromide spills, make sure there is adequate ventilation and clean up the liquid with an inert material like earth or dry sand[11]
References
edit- ^ "Bromoacetyl bromide". Retrieved 18 October 2012.
- ^ "Bromoacetyl Bromide: A Versatile and Selective Cleaving Agent for Ethers and Acetals". Retrieved 24 November 2012.
- ^ "Ultrasonic preparation of cationic cotton and its application in ultrasonic natural dyeing". Ultrasonic Sonochemistry. Retrieved 25 November 2012.
- ^ "Bromoacetyl bromide". Retrieved 18 October 2012.
- ^ "Bromoacetyl Bromide Properties". Retrieved 18 October 2012.
- ^ "Bromoacetyl bromide". Retrieved 18 October 2012.
- ^ "University of Akron". Retrieved 13 November 2012.
- ^ "Bromoacetyl bromide". Retrieved 18 October 2012.
- ^ "Hazardous Substance Fact Sheet" (PDF). Retrieved 27 November 2012.
- ^ "Emergency Response Guide" (PDF). Retrieved 28 November 2012.
- ^ "University of Akron". Retrieved 13 November 2012.