The transition from non-renewable to renewable energy sources is a significant challenge of our time. In the fuel industry, oxygenated additives such as butanol are transforming conventional fuels into renewable biofu...The transition from non-renewable to renewable energy sources is a significant challenge of our time. In the fuel industry, oxygenated additives such as butanol are transforming conventional fuels into renewable biofuels. This technology has been utilized in reciprocating engines for decades. This paper reviews the viability of using an n-butanol blend as a short-term replacement for diesel by analyzing its physical and chemical properties, combustion, performance, and emission characteristics in compression ignition (CI) engines under various conditions, including variable load, speed, acceleration, and both stationary and transient cycles. N-Butanol exhibits higher viscosity, better lubricity, higher heating value, improved blend stability, enhanced cold-flow properties, and higher density. These factors influence spray formation, injection timing, atomization, and combustion characteristics. Its higher oxygen content improves the diffusion combustion stage and efficiency. Adding 5% and 10% n-butanol to diesel increases pressure and apparent heat release rate, slightly reduces temperature, and improves thermal efficiency, with mixed effects on CO and THC emissions and a notable decrease in particulate matter emissions. Fuel consumption increases, while the impact on NOx emissions varies. A 10% butanol blend is considered optimal for enhancing performance and reducing particulate emissions without significantly affecting NOx emissions. Blending up to 40% butanol with diesel does not require engine modifications or ECU recalibrations in engines calibrated for pure diesel. Due to its advantageous properties and performance, n-butanol is recommended as a superior alcohol-diesel blend than ethanol for short-term diesel replacement.展开更多
A series of enantiomencally pure (4R,5R)-(-)-4-alkryloxy-5-[(1R,2dihydro-2(5H)-furanones (2) have been synthesized in excellent yields via asymmetric conjugateadditions of primary alcohols to (R)-(-)-5-[(1R,2S,5R)-men...A series of enantiomencally pure (4R,5R)-(-)-4-alkryloxy-5-[(1R,2dihydro-2(5H)-furanones (2) have been synthesized in excellent yields via asymmetric conjugateadditions of primary alcohols to (R)-(-)-5-[(1R,2S,5R)-menthyloxy]-2(5H)-furanone (1) in the presenceof a catalytic amount of sodium in DMF, which provides access to new multifunctional homochiralbuilding blocks, optically. pure (R) or (S)-2-alkyloxy- 1,4-butanediols (3).展开更多
New polyurethanes based on bile acids were synthesized from alcohol derivatives of cholic and lithocholic acids and hexamethylene diisocyanate, in an effort to improve the biocompatibility and biodegradability of poly...New polyurethanes based on bile acids were synthesized from alcohol derivatives of cholic and lithocholic acids and hexamethylene diisocyanate, in an effort to improve the biocompatibility and biodegradability of polyurethanes through the use of natural compounds. The hydrogen bonding in the polymers is confirmed by IR spectral analysis. The glass transition temperatures of the polymers are in the range of 82-138 ℃ and degradation temperatures in the range of 267-298 ℃ as studied by thermal analyses. Thermogravimetric studies indicate that the comonomers are of equimolar amounts in the polyurethanes derived from both bile acids.展开更多
文摘The transition from non-renewable to renewable energy sources is a significant challenge of our time. In the fuel industry, oxygenated additives such as butanol are transforming conventional fuels into renewable biofuels. This technology has been utilized in reciprocating engines for decades. This paper reviews the viability of using an n-butanol blend as a short-term replacement for diesel by analyzing its physical and chemical properties, combustion, performance, and emission characteristics in compression ignition (CI) engines under various conditions, including variable load, speed, acceleration, and both stationary and transient cycles. N-Butanol exhibits higher viscosity, better lubricity, higher heating value, improved blend stability, enhanced cold-flow properties, and higher density. These factors influence spray formation, injection timing, atomization, and combustion characteristics. Its higher oxygen content improves the diffusion combustion stage and efficiency. Adding 5% and 10% n-butanol to diesel increases pressure and apparent heat release rate, slightly reduces temperature, and improves thermal efficiency, with mixed effects on CO and THC emissions and a notable decrease in particulate matter emissions. Fuel consumption increases, while the impact on NOx emissions varies. A 10% butanol blend is considered optimal for enhancing performance and reducing particulate emissions without significantly affecting NOx emissions. Blending up to 40% butanol with diesel does not require engine modifications or ECU recalibrations in engines calibrated for pure diesel. Due to its advantageous properties and performance, n-butanol is recommended as a superior alcohol-diesel blend than ethanol for short-term diesel replacement.
文摘A series of enantiomencally pure (4R,5R)-(-)-4-alkryloxy-5-[(1R,2dihydro-2(5H)-furanones (2) have been synthesized in excellent yields via asymmetric conjugateadditions of primary alcohols to (R)-(-)-5-[(1R,2S,5R)-menthyloxy]-2(5H)-furanone (1) in the presenceof a catalytic amount of sodium in DMF, which provides access to new multifunctional homochiralbuilding blocks, optically. pure (R) or (S)-2-alkyloxy- 1,4-butanediols (3).
基金supported by the NSERC,FQRNT and the Canada Research Chair program
文摘New polyurethanes based on bile acids were synthesized from alcohol derivatives of cholic and lithocholic acids and hexamethylene diisocyanate, in an effort to improve the biocompatibility and biodegradability of polyurethanes through the use of natural compounds. The hydrogen bonding in the polymers is confirmed by IR spectral analysis. The glass transition temperatures of the polymers are in the range of 82-138 ℃ and degradation temperatures in the range of 267-298 ℃ as studied by thermal analyses. Thermogravimetric studies indicate that the comonomers are of equimolar amounts in the polyurethanes derived from both bile acids.
