Question

In: Chemistry

from the three isomers of 1,2-dibromo-1,2-diphenylethane. 1) Name one green chemistry principle for which each reaction...

from the three isomers of 1,2-dibromo-1,2-diphenylethane.

1) Name one green chemistry principle for which each reaction shows improvement over the traditional process, one for which each reaction is less favorable compared to the traditional process and explain how they apply to the reactions.

Solutions

Expert Solution

Atom economy in syntheses

The concept of atom economy can also applied to syntheses. To determine the atom economy of a synthesis, one simply must determine which of the atoms of the reactants for all steps in the synthesis are incorporated into the desired final product.

Synthesis of Ibuprofen

The Boots Company Synthesis of Ibuprofen
    Ibuprofen is the active ingredient in a number of brand name products including Advil, Motrin and Nuprin. Ibuprofen acts as an analgesic (pain reliever) and is also effective as a Non Steroidal Anti-Inflammatory Drug (NSAID). NSAIDs reduce inflammation from such conditions as arthritis, osteoarthritis and rheumatism. Ibuprofen is referred to as a non steroidal anti-inflammatory drug since ibuprofen is not a member of the steroid family of compounds.
    The world production of ibuprofen exceeds 30 million pounds per year. The Boots Company PLC of Nottingham, England first patented the synthesis of ibuprofen in the 1960's (U.S. Patent 3,385,886) and this has served as the main method of synthesis for many years. The Boot's synthesis of ibuprofen is a six-step synthesis and is shown in Scheme 3. As usual all the

Scheme 3 The Boots Synthesis of Ibuprofen

atoms of each reagent that are incorporated into the final desired product (ibuprofen) are shown in green and those that end up in unwanted products are shown in brown. Table 10 illustrates the atom economy of the Boots Company synthesis and allows one to calculate a percentage atom economy of 40%. As was indicated above about 30 million pounds of ibuprofen are manufactured on a yearly basis. If all the world's supply of ibuprofen were manufactured by the Boots process, then this would generate about 35 million pounds of waste!

Table 10        Atom Economy of Scheme 3, the Boots Company Synthesis of Ibuprofen

Reagents Formula Reagents FW Utilized Atoms Weight of  
Utilized Atoms
Unutilized  
Atoms
Weight of  
Unutilized Atoms
1   C10H14           134        10C,13H          133      H       1
2   C4H6O3           102           2C,3H            27      2C,3H,3O      75
4 C4H7ClO2          122.5            C,H            13     3C,6H,Cl,2O     109.5
5 C2H5ONa            68           _____              0     2C,5H,O,Na       68
7 H3O            19           _____            0     3H,O       19
9 NH3O            33           _____            0     3H,N,O       33
12 H4O2            36          H,2O            33     3H         3
Total
20C,42H,N,10O,
Cl,Na
         514.5       Ibuprofen
    13C,18H,2O
      Ibuprofen
         206
Waste Products
7C,24H,N,8O,
Cl,Na
Waste Products
    308.5

% Atom Economy = (FW of atoms utilized/FW of all reactants) X 100
                                        = (206/514.5) X 100 = 40%

        The BHC Company Synthesis Of Ibuprofen

    In the eighties ibuprofen was approved for over-the-counter use and the Boots Company patent expired. Recognizing the financial opportunities that the manufacture and sales of this drug could offer, several companies embarked upon setting up facilities and developing new methods for the preparation of ibuprofen. The Hoechst Celanese Corporation (Somerville, NJ; now know as the Celanese Corporation) discovered a new three-step synthesis of ibuprofen. Together with the Boots Company they formed the BHC Company to prepare (by the new synthesis) and market ibuprofen. The BHC Company synthesis is show in Scheme 4 with the utilized atoms in green and the untutilized atoms in brown. The atom economy is further illustrated in Table 11 and calculation of the % atom economy gives 77%, a significant improvement over the 40% of the

Scheme 4 The BHC Company Synthesis of Ibuprofen


  

Table 11        Atom Economy of Scheme 4, the BHC Company Synthesis of Ibuprofen

Reagents Formula Reagents FW Utilized Atoms Weight of  
Utilized Atoms
Unutilized  
Atoms
Weight of  
Unutilized Atoms
1   C10H14          134        10C,13H          133      H       1
2   C4H6O3          102         2C,3H,O            43      2C,3H,2O      59
4   H2              2            2H            2       _____        0
6 CO            28           CO            28       _____        0
Total
15C,22H,4O
         266     Ibuprofen
   13C,18H,2O
         206 Waste Products
     2C,3H,2O
     60

% Atom Economy = (FW of atoms utilized/FW of all reactants) X 100
                                        = (206/266) X 100 = 77%

Boots Company process. The atom economy of the BHC Company process jumps to >99% if one considers that the acetic acid generated in Step 1 is recovered and used.

    Not only does the BHC Company process offer a dramatic improvement in the atom economy it offers other environmental advantages. These include a three-step catalytic process vs. the six-step Boots Company process that requires auxiliary reagents in stoichiometric amounts. For example, the first step in each process yields the same product (3) from the same reactants (1 and 2). However, the Boots Company process utilizes aluminum trichloride in stoichiometric amounts (not accounted for in Table 10) while the BHC Company process uses HF in catalytic amounts that is recovered and reused repeatedly. The aluminum trichloride produces large amounts of aluminum trichloride hydrate as a waste product which is generally landfilled. The nickel and palladium catalysts used in Steps 2 and 3 of the BHC Company process are also recovered and reused.


Related Solutions

Name one green chemistry principle that could have the greatest potential to minimize the future impact...
Name one green chemistry principle that could have the greatest potential to minimize the future impact of each of Chlorofluorocarbons; CF2Cl2 and Hydrochlorofluorocarbons: HCF2Cl , explaining how EACH green chemistry principle can be applied specifically to each chemical.
The criminal justice system has three components. Name and define each of the components. Which one...
The criminal justice system has three components. Name and define each of the components. Which one is in need of the most comprehensive overall at this time in our history and why?
1) For the following reaction at equilibrium in a reaction vessel, which one of these changes...
1) For the following reaction at equilibrium in a reaction vessel, which one of these changes would cause the Br2 concentration to decrease?  2NOBr(g)  2NO(g) + Br2(g), ∆Horxn= 30 kJ/mol A) Increase the temperature. B) Remove some NO. C) Add more NOBr. D) Compress the gas mixture into a smaller volume.
Name four types of information bias. Name at least one way in which each type of...
Name four types of information bias. Name at least one way in which each type of bias can be prevented or minimized.
Name three types of taxes and analyze the deadweight loss of each. Which of these taxes...
Name three types of taxes and analyze the deadweight loss of each. Which of these taxes do you believe create the highest deadweight loss? Why? Why is deadweight loss disagreed on by experts? Explain.
1. Name the three types of decelerations, their causes, and the interventions for each. Explain the...
1. Name the three types of decelerations, their causes, and the interventions for each. Explain the differences between internal and external fetal monitoring. . Which FHR pattern is treated with an amnioinfusion?
Chose one character from each of these three stories and write an introduction paragraph: (1) The...
Chose one character from each of these three stories and write an introduction paragraph: (1) The story of an hour. (2) A Rose for Emily. (3) The Lottery.
Name and define three bank off-balance sheet items. Provide examples (one for each) of how each...
Name and define three bank off-balance sheet items. Provide examples (one for each) of how each of these items can give rise to changes on the financial statements (statement of condition or statement of income)
Name three professions related to kinesiology and explain how each will benefit from a knowledge of...
Name three professions related to kinesiology and explain how each will benefit from a knowledge of biomechanics.
1. Name three observations/signs that might indicate that a chemical reaction has occurred. 2. Write a...
1. Name three observations/signs that might indicate that a chemical reaction has occurred. 2. Write a balanced chemical equation for the reaction of iron with oxygen to form iron oxide (Fe2O3). Then write a description of what you would observe as a piece of iron rusts. What was the sign of the chemical reaction in which iron rusts into iron(III) oxide? 3. Define the following terms:      oxidation-     reduction- 4. For the reaction in question 2, which reactant is...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT