Questions and Answers
What is the starting material used in the green route to styrene production?
What is the primary concern associated with polyacrylates?
Which catalyst is used in the traditional route for styrene production?
Which of the following is a key characteristic of polyaspartates compared to polyacrylates?
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What is one of the by-products generated in the traditional route for allyl alcohol production?
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What is the source material for synthesizing polyaspartates?
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What is the overall selectivity to styrene in the green route using toluene and methanol?
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Which application is NOT mentioned for polyacrylates?
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In the green route to allyl alcohol, which reactants are used in the first step?
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Which property of polyaspartates makes them a suitable alternative to polyacrylates?
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What is a notable property of polyaspartate?
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What are the components used to synthesize polyaspartate?
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Which organization awarded the Donlar Corporation for its green chemistry innovations?
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What type of award did the Donlar Corporation receive in 1996?
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What chemical reaction occurs during the synthesis of polyaspartate?
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In which category did the Donlar Corporation win the Presidential Green Chemistry Challenge Award?
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What role does NaOH play in the synthesis of polyaspartate?
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What is the relationship between polyaspartate and aspartic acid?
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What was the main disadvantage of the Boots process for ibuprofen in the 1960s?
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How many steps did the Hoechst-Celanese process use for ibuprofen synthesis?
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What type of linkage was primarily utilized in Donlar's polyaspartates manufacturing facility?
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In what year did Boots win the Queens Award for Technical Achievement?
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Which award did the Hoechst-Celanese process win in 1991?
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What temperature range is optimal for microwave processing in high-temperature water reactions?
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What is a limitation of pure water in microwave heating as temperatures increase?
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What percentage of atom efficiency does the Hoechst-Celanese process claim for its steps?
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What was a major characteristic of the Boots process compared to the Hoechst-Celanese process?
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What is a common feature of the processes for synthesizing ibuprofen mentioned in the content?
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Study Notes
Case Studies - Green Chemical Products
-
Styrene Production
- Traditional two-step method starts with benzene and ethylene for ethylbenzene, followed by dehydrogenation.
- Step II uses Fe-oxide catalyst and K2CO3 promoter, achieving 65% conversion and 95-97% selectivity to styrene.
- Green route utilizes xylene as a less toxic starting material, converting to styrene via toluene and methanol at >400 °C using a proprietary zeolite catalyst.
- Overall selectivity to styrene in the green process is approximately 60% at 1 atm pressure, making it the cheapest route.
-
Allyl Alcohol Production
- Traditional method involves alkaline hydrolysis of allyl chloride, producing hydrochloric acid as a by-product.
- The Shell process uses NaOH, resulting in significant NaCl generation.
- Green synthesis avoids chlorine by processing propylene, acetic acid, and oxygen in two steps: acetoxylation followed by hydrolysis.
- Acetic acid from hydrolysis can be reclaimed for reuse, providing a sustainable cycle.
- An alternative method uses glycerol reacting with formic or oxalic acids.
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Thermal Polyaspartate as an Alternative to Polyacrylates
- Polyacrylates are widely used in products like paints, fibers, resins, and cosmetics but raise concerns about degradability.
- Polyaspartates, developed by Donlar Inc., are biodegradable biopolymers derived from L-aspartic acid with no waste by-products.
- Exhibit similar properties to polyacrylates, making them suitable for applications as dispersants and superabsorbers.
- Donlar Corporation won the 1st Presidential Green Chemistry Challenge Award in 1996 and opened the largest polyaspartates facility in 1997.
Green Reaction Conditions
-
Ibuprofen Production
- The Boots process from the 1960s involved 6 steps with stoichiometric reactions, leading to chemical waste and high costs.
- Boots was recognized with the Queens Award for Technical Achievement in 1987 for their contributions.
- Hoechst-Celanese developed a more efficient green chemistry method with only 3 catalytic steps, achieving 100% atom efficiency.
- The HC process received the Kirkpatrick Award in 1991 for its innovative use of catalytic processes over traditional stoichiometric methods.
Green Modes of Activation
- High-temperature water reactions (100–200 °C) are optimal for microwave processing in sealed vessels.
- Challenges arise as pure water's absorbance of microwave energy decreases above 130 °C, complicating heating efforts.
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Description
Dive into the case studies of green chemical products, focusing on styrene production. This lecture explores traditional and innovative methods, including the use of Fe-oxide catalysts. Learn about the efficiency and environmental impact of these processes.
