Preparation and Characterization of Alkene

Only available on StudyMode
  • Topic: Sulfuric acid, Distillation, Alkene
  • Pages : 8 (2212 words )
  • Download(s) : 88
  • Published : March 5, 2012
Open Document
Text Preview
Preparation and Characterization of Alkene

Balacanao, Gladys A.1, Miranda, MarilynI2

1 Student (s), Subject/Section, School of Chemical Engineering, Chemistry and Biotechnology, Mapua Institute of Technology; 2 Professor, School of Chemical Engineering, Chemistry and Biotechnology, Mapua Institute of Technology [pic]

ABSTRACT
The purpose of this experiment is to prepare cyclohexene form cyclohexanol, and know the properties of alkene. The first part of this experiment is preparation of cyclohexene. Simple distillation set-up is assembled. (See Figure 1). Exactly 6.0mL of cyclohexanol is weighed in a quick-fit one-necked pear shaped flask. 1.50mL of 85% H3PO4 is measured using the 2mL pipet and added to the weighed cyclohexanol. Another 0.25mL of concentrated H2SO4 is also added. The reagents are mixed using stirring rod. Glass beads were added after it was shake very well. The heat regulator was switched to 5 or 6 and allowed to distill at 130-140°C until 0.50mL of the mixture was left in the pear-shaped flask. The hydrocarbon layer of the distillate (mixture of cyclohexene and water) was transferred to another test tube using dropper. The hydrocarbon layer was extracted twice with 2.0mL of cold water. Anhydrous calcium chloride powder was added to the hydrocarbon layer (enough to still see the liquid) and stirred occasionally for 6minutes. The solid was allowed to settle down. The liquid part of the mixture was removes using pipet and transferred to the 25mL quick-fit round bottom flask. Simple distillation set-up is again assembled. The hydrocarbon was distilled and the distillate at 82-85°C was collected. The receiver was weighed in order to get the weigh of the distillate to be used for computing the percentage recovery. The second part of this experiment is properties of alkene. The prepared cyclohexene was used as test compound. For flammability, 2 drops of the compound was placed in an n evaporating dish and lit with match. For solubility, 2 drops of compound was placed in a micro test tube, and 0.50mL of water was added. For, bromination, 2 drops of compound was placed in a micro test tube. 1M Br2 in CCl4 was added dropwise, and shaken until change is observed. For oxidation, 2 drops of compound was placed in a micro test tube. 1M KMnO4 was added dropwise, shaken, and observed for 2minutes. For sulfuric acid test, 2 drops of compound was placed in a micro test tube. 0.50mL of concentrated H2SO4 was added, and observed if formation of heat is present. Keywords: albumin, casein, invertase, Bradford Assay, Warburg-Christian Assay, Benedict’s reagent[pic] INTRODUCTION

Alkenes are more reactive than alkanes due to the presence of a double bond. The carbon-carbon double bond consists of a strong bond and a weak p bond. The typical reactions of alkenes involve the breaking of this weaker p bond, viz., and formation of two sigma (s) bonds.

[pic]

through ionic mechanism. However, some addition reactions proceed through free-radical mechanism.

Higher alkenes contain a long chain of carbon. That part of the chain that forms an alkane-like structure (consisting of C-C bonds), may undergo substitution reaction as also shown by alkanes. Some characteristic reactions shown by alkenes are described below:

Combustion
-Alkenes, like alkanes, are highly combustible. Alkenes burn with a luminous flame to give carbon dioxide and water. The flame becomes luminous because of the higher carbon content of alkenes than alkanes. Their combustion reactions are exothermic.

[pic]

Due to the luminosity of the flame, the lower alkenes may be used as illuminants.

Addition reactions
-The p electrons of the carbon-carbon-double bond are available to an electrophile (any species seeking electrons). Thus, the addition reactions shown by alkenes are in fact electrophilic addition reactions.

[pic]
[pic]
addition product

Some addition reactions proceed through free-radical mechanism.

Addition of hydrogen...
tracking img