Examine the Reaction Between Benzaldehyde and Acetone or Benzaldehyde and Cyclopentanone to Form Dibenzylideneacetone or Dibenzylidenecyclopentanone
Essay Preview: Examine the Reaction Between Benzaldehyde and Acetone or Benzaldehyde and Cyclopentanone to Form Dibenzylideneacetone or Dibenzylidenecyclopentanone
Report this essay
Objective: The purpose of this experiment is to examine the reaction between benzaldehyde and acetone or benzaldehyde and cyclopentanone to form dibenzylideneacetone or dibenzylidenecyclopentanone, respectively. The products will be analyzed by ultraviolet spectroscopy to determine with compound makes a better UVA sunscreen.
Procedure: For detailed procedure, please see Chemistry 235 Laboratory Manual, pages 75-78 and additional handout.1
Table 1: Reagents
Compound
Molecular Weight (g/mol)
Physical and Safety Data
3M NaOH
39.99
10.0mL= 2.2g = 0.0300 mol
D=2.13 g/mL, bp 1388C. Corrosive
Benzaldehyde
106.12
1.06 g, 1.0mL = 0.0100 mol
1.0415 g/mL, bp178.1. Irritant
Cyclopentanone
84.12
8mL. 420 mg.
Irritant
Ethanol
46.07
2x10mL
bp 78, mp= -114. Irritant, toxic.
Chloroform
119.38
mp= -63.5, bp 61.2. d= 1.483 g/mL. Harmful, irritant.
Table 2: Products
Compound
Safety
Amount Collected
Molecular Weight (g/mol)
% Yield
Dibenzylidenecyclopentanone
Irritant
0.939 g
260.33
72.2%
Table 3: Ultraviolet Spectroscopy
Compound
Absorbance max
Wavelength Range of Absorption
Dibenzylidenecyclopentanone
355.0 nm
0.825
280-410
Dibenzylideneacetone2
323.0 nm
0.375
260-375
Calculations:
%Yield:
% Yield = Actual Yield (grams)/ Theoretical Yield (grams)
Theoretical Yield = 0.005 mol (limiting reagent) * 260.33 g/mol = 1.30 g
= (0.939 g/ 1.30 g) * 100% = 72.2%
Dilution Equation for Dibenzylidenecyclopentanone:
M1V1 = M2V2
M1: 0.009g x (1mol/260.33g) = 0.000035 mol
0.000035 mol/ 0.025 L = 0.00138 mol/L
V1= x
M2 = 2x 10-5 mol/L
V2 = 0.010 L
V1= [(2x 10-5 mol/L)(0.010L)/ 0.00138 mol/L)
= 0.00014 L = 140 uL
Dilution Equation for Dibenzylideneacetone2:
M1V1 = M2V2