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Questions and Answers
Which of the following is a method used to enhance energy efficiency in chemical reactions?
Which of the following is a method used to enhance energy efficiency in chemical reactions?
Microwaves operate at wavelengths from 1 cm to 1 m.
Microwaves operate at wavelengths from 1 cm to 1 m.
True (A)
What role do catalysts play in enhancing chemical reactions?
What role do catalysts play in enhancing chemical reactions?
Lowering the activation energy required for the reaction.
Microwaves are absorbed by polar molecules, such as those of __________.
Microwaves are absorbed by polar molecules, such as those of __________.
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Match the following energy efficiency methods with their descriptions:
Match the following energy efficiency methods with their descriptions:
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What is a characteristic feature of green solvents?
What is a characteristic feature of green solvents?
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Adding energy to a chemical reaction can only be done by heating.
Adding energy to a chemical reaction can only be done by heating.
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What are two advanced methods of energizing chemical reactions mentioned?
What are two advanced methods of energizing chemical reactions mentioned?
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Which method can be used to enhance reactions in water media?
Which method can be used to enhance reactions in water media?
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A cathode is where oxidation occurs during electrochemical reactions.
A cathode is where oxidation occurs during electrochemical reactions.
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What is the primary advantage of sonochemistry?
What is the primary advantage of sonochemistry?
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The energy of a photon of electromagnetic radiation is calculated using the formula E = _______.
The energy of a photon of electromagnetic radiation is calculated using the formula E = _______.
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Match the following energy methods with their primary characteristics:
Match the following energy methods with their primary characteristics:
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Which of the following is true about electrolytic syntheses?
Which of the following is true about electrolytic syntheses?
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Electrochemical processes cannot be controlled by the type of electrodes used.
Electrochemical processes cannot be controlled by the type of electrodes used.
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What frequency range is utilized in sonochemistry?
What frequency range is utilized in sonochemistry?
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Study Notes
Alternative Organic Solvents
- Alternative organic solvents are liquid substances used in applications to dissolve other substances.
- The solvent can be recovered unchanged after removal.
- Research in green chemistry focuses on environmentally benign and economically feasible chemical processes and syntheses.
- The goal of green chemistry is to reduce hazards from products and processes.
Solvent Usage
- Solvents are crucial in various industrial and laboratory applications.
- They extensively participate in reactions, work-ups and purifications.
- Solvents are used in coatings, like paints and adhesives.
- Removal of solvents often occurs through evaporation.
Wide Applications
- Solvents are vital in synthetic and analytical chemistry.
- They act as reaction media in laboratory and industrial processes.
- Solvents are extensively used in work-up and purification stages.
- Solvents are important for sample extraction and preparation.
- They are used in chromatography techniques such as HPLC and TLC.
- Solvents are crucial for crystal purification and analysis through recrystallization techniques.
Criteria for Solvent Selection
- Evaluation of the necessity of the substance.
- Identification of less toxic alternatives.
- Assessment of risks and benefits for continued usage.
- Evaluation of environmental impact.
- Analysis of resource depletion during procurement.
- Examination of successful final disposal methods.
- Determination of safe usage technologies.
Solvents as Green Chemistry Tools
- Understanding the hazardous properties of a chemical.
- Manipulating chemical structures to mitigate hazards.
Solvents Effects and Green Chemistry
- Studying solvent effects requires employing conceptual approaches such as theories of molecular structures and the concept of polarity.
- Bulk properties encompass dielectric constants and density.
Goals of Green Chemistry
- The goal of green chemistry includes minimizing hazards involved in products and processes.
- This aims to enhance not only the quality of life but also technical achievements.
- Risk = Hazard × Exposure.
Green Solvents & Definitions
- An ideal green solvent combines safety for humans with reduced hazards and easy degradability.
- High product yield is an additional desirable characteristic.
- The solvent should have less human and environmental absorption.
- Understanding environmental toxicity and environmental fate is crucial for solvent selection.
Greener Solvent Alternatives
- Water (including supercritical water), methanol, nitromethane, ethanol, DMF, DMSO, HMPA, acetonitrile, pyridine and ammonia are some greener solvents.
- Ionic liquids, perfluorinated hydrocarbons, and supercritical fluids are also potential greener alternatives.
Water as a Reaction Medium
- Water is a cost-effective and readily available alternative to volatile organic compounds (VOCs).
- It is beneficial in certain reactions but limited by low solubility with organic substrates and issues with waste disposal.
- It is useful in biphasic processes combined with other solvents.
Water as Dual Activator Medium
- Water's hydrogen bonding capability enables it to activate both nucleophiles and electrophiles, thus accelerating polar reactions.
Carbon Dioxide
- Carbon dioxide (CO2) offers advantages resembling water, being natural, inexpensive, abundant, readily available in high purity, and a byproduct.
- Its non-toxicity and well-understood properties are valuable too.
- It is easily removed and recycled.
- CO2 facilitates solvent-free product isolation with 100% dryness.
- It has potential in diverse product processing steps like extraction, particle formation, or chromatography.
Supercritical Fluids (SCFs)
- SCFs are substances neither gaseous nor liquid, possessing properties of both.
- No sharp boundary between gas and liquid phases exists.
- Carbon dioxide (CO2) and water are examples of SCFs.
Possible Advantages of Supercritical Fluids
- Increased solubilities of reactants or products leading to homogenous phases, eliminating transport limitations.
- Recovering SCFs, such as water and CO2. has low environmental impact.
- Fine-tuned reaction conditions through pressure and temperature adjustments.
- Elimination of separation steps.
- Solubility of organic compounds in SCFs; insolubility of inorganic salts.
Advantages of ScCO2
- High compressibility allows significant solvent property adjustments with minor pressure changes.
- Tailoring solvent properties for targeted reaction pathways and increased reaction rates.
- Low molecular diffusion rates are also possible.
Extraction using ScCO2
- ScCO2 excels in decaffeinating and brewing processes.
- It is used for essential oils and fragrances extraction.
- An environmentally friendly extraction method.
Ionic Liquids (ILs)
- ILs typically comprise an organic cation (often ammonium or phosphonium salt) and an inorganic anion.
- They are typically liquid at room temperature.
- Diverse structures are possible.
- Their low vapor pressure is beneficial in comparison to volatile organic compounds (VOCs).
Ionic Liquids as Reaction Media
- ILs are promising media for various chemical reactions.
- They are capable of facilitating Diels-Alder reactions, alkylation, hydroformylation, and Friedel-Crafts reactions.
- They also contribute to Pd-mediated C-C bond formation and alkene polymerisation.
- Ionic Liquids applications in biotransformation processes.
Ethyl Lactate
- Ethyl lactate is derived from corn processing.
- It displays a variety of possible lactate esters.
- This is a renewable resource, non-petrochemical-based solvent.
- It is biodegradable, recyclable, and non-corrosive.
- It's non-carcinogenic and non-ozone depleting.
- This is a good solvent for various processes and commonly employed in the paint and coatings industry.
Specific Health & Environmental Requirement
- Specific health and environmental requirements encompass: toxic chemicals, carcinogens and reproductive toxins, flammability, ozone depletion, and aquatic life toxicity.
- Characterization of solvents based on their LD50 (lethal dose) values.
Flammability
- The solvent's flash point should be above 100°F to prevent flammability risks.
Ozone Depletion
- Solvents should not contain Class-I or Class-II ozone-depleting substances.
Toxicity to Aquatic Life
- Solvents should not harm aquatic life.
Green Solvents for Academic Chemistry
- Teaching environmental impact alongside basic chemistry is important for non-science students.
- Focusing on environmental aspects of chemistry, along with fundamental chemical processes and related points concerning efficiency and pollution.
Physical Properties of Solvents
- Solvent physical properties heavily influence applications.
- Liquid state is necessary under the specific temperature and pressure conditions.
- Identifying thermodynamic properties (density, vapor pressure, temperature, and pressure coefficients, heat capacity and surface tension).
- Understanding transport properties (viscosity, diffusion coefficient and thermal conductivity).
Chemical Properties of Solvents
- Chemical properties critically affect the suitability for various uses.
- Structure plays a key role in properties such as volatility, viscosity, diffusion coefficient and relaxation rates.
- Properties, such as stiffness and openness.
- Solvent properties like polarity are influenced by intermolecular forces and are characterized by dipole moments.
Application of Green Solvents
- Green solvents find applications in new syntheses.
- They are valuable in integrated circuit production, removing pollutants from wood, developing new pesticides, and purifying water.
- They contribute to environmentally responsible paint and coating production, and the development of recyclable carpeting materials.
- Replacing volatile organic compounds (VOCs) and chlorinated solvents.
- Biodegradable polymers are used for sustainable purposes.
Energy Efficiency
- Enhancing reaction rate(s) or improving chemical reaction completion through energy efficiency methods like lowering activation energy, using catalysts.
- Reducing energy usage by using ambient temperatures and/or pressures where possible.
- Implementing more efficient ways to use non-renewable sources of energy.
Energy Efficiency Example
- Employing microwave irradiation, sonochemistry, electrochemistry or photochemistry to expedite reactions and reduce resource consumption.
Applications area of Energy Efficiency
- Incorporating renewable energy into buildings.
- Developing more energy-efficient vehicles.
- Upgrading homes with energy-efficient products.
- Implementing energy-efficient processes in industries.
- Utilizing low-power modes for computers and laptops.
Need to Design Energy Efficiency
- Reducing the greenhouse effect by adopting energy-efficient solutions.
- Controlling energy consumption through household and economic practices.
- Reducing energy imports by fostering energy efficiency.
Conclusion
- Energy efficiency, a cost-effective method, combats climate change.
- It reduces costs for consumers and enhances business competitiveness.
- Energy efficiency is essential to decarbonization and achieving net-zero carbon emissions.
- It leads to a resilient electric grid and provides environmental, community and health benefits.
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Description
Explore the significance of alternative organic solvents in chemistry and their applications in various industries. This quiz covers the role of solvents in processes, their impact on the environment, and the principles of green chemistry. Understand the methods of solvent recovery and their usage in analytical techniques.
