Green Chemistry: Using green solvents and green methods for synthesis part 2

Derivatized and immobilized solvents

·         Corresponding solvent properties, but lower volatility (= less VOC)

·         Easier separation·         Less emissions into waste water streams

·         Expensive·         Total effect on the environment unclear (LC-analysis)

·         Recyclability unclear

Areas of use: THF and dichloromethane derivative

Maturity of technology: early R&D stage

Processes without solvent

Definition: Solvents or inerts are not applied: all the components in the reaction mixture will be included in the products.

·         avoiding VOC formation

·         Processes often energy intensive

·         Viscosity limits

·         Products often not so clean as when using solvents

Areas of use: some polymers, coatings, oxidation of alcohols

Maturity of technology: coatings in industrial use, synthesis in R&D stage

CO2 as raw material

·         Desire to decrease CO2

-emissions as a starting point

o   comparison of processes partly based on environmental considerations (e.g. LCA comparison)

·         Possible products: specialty chemicals, polymers, diamonds, bio

·         Specialty chemicals

o   high atom economyo   the only byproduct is water

o   Thermodynamics of the reactions that use CO2 as raw material is more unfavourable than the current technology (however possible!)

o   How in the energy produced, is it any more environmentally friendly?

Oxidation reactions

Production of specialty chemicals (epoxides, alcohols, alkenes, etc.)

Current technology:–

Stoichiometric inorganic and organic oxidizers

e.g. dichromate/sulphuric acid, chromium oxides 

Ø  plenty of wasteAlternative:Catalyst + O2 or H2O2 or N2O

+ H2O2 existing equipment can be used (Enichem process)

– H2O2 price has been preventing commercialization

Ø  In situ H2O2 forming? Is oxidation selective?

Oxidation reactions -alcohols

Traditional technology:–

Stoichiometric amounts

– Heavy metal catalyst (Cr)

– Difficult solvents (chlorinated hydrocarbons)

More ecological technology:

• Pd + ligand or Ru + ligand+ Molecular oxygen (O2) or hydrogen peroxide (H2O2)

+ Atom economy

+ The only byproduct H2O