1. Doing without Phosgene, Hydrogen Cyanide, and Formaldehyde
PART II

2. Reducing Toxicity of Isocyanates
Associated with occupational asthma;
Require a hood;
toluenediisocyanate
Ways to reduce toxicity:
-Increasing MW;
- Chemical conversion;

3. Chemical Conversion of Isocyanates
1. Conversion to carbodiimides
RNCO
2. Reaction with polymeric diol

4. Various HA Agents Can Add to Isocyanate Group
alchohol
isocyanate
polyurethane
amine
isocyanate
polyurea
-used to inactivate isocyanate group
-require thermal unblocking
-volatile blocking agent

5. Blocked Prepolymer Mixtures
Methyl ethyl ketoxime
Tengfei Shen, Mangeng Lu, Liyan Liang; Synthesis and properties of biodegradable polyurethane crosslinkers from methyl ethyl ketoxime-blocked diisocyanate. Macromolecular Research, August 2012, Volume 20, Issue 8, pp

6. Thermally Reversible Polyurethane Polymers
Dissociation Temperature
Alcohol > Lactam > phenol > ketoxime >active methylene compound
1,4-butanediol
4,4’-isopropylidendipenol (bisphenol A, BPA)
4,4-diphenyldiisocyanate

7. 4,4’-Isopropylidendipenol (bisphenol A, BPA)

8. Polymerization of Isocyanate Monomers

9. Polymers Made without Isocyanates: Reactions of Cyclic Carbonates with Diamines
Contras: low MW (9350 and 5345)
Possible solution: use chain extension agents

10. Reactions of Cyclic Carbonates with Diamines

11. Applications of Polycarbonate Polymers

12. Polycarbonates Traditional polycarbonate synthesis involves phosgene
Solvent: methylene chloride
Base: pyridine, NaOH

13. Ester Exchange Method for Polycarbonate Synthesis
No solvents, no salt by-products
Needs:
High temperature
Vacuum/N2 flow to extract phenol

14. CO2 Can Be an Alternative to CO in Polycarbonates Synthesis

15. Summary for Phosgene
Elimination of phosgene in PC production is getting commercialized
(SABIC, Asahi, Mitsubishi)
Non-Phosgene Polycarbonate from CO2 - Industrialization of Green Chemical Process
Authors: Shinsuke Fukuoka (Asahi Kasei Chemicals Corporation)
Chapter 1. Introduction: Society And Chemical Industry Chapter 2. Background Of Polycarbonate Chapter 3. General Method For Synthesis Of Polycarbonate Chapter 4. Technological Aspects Of The Industrial Processes For Producing Aromatic Polycarbonates Using Carbon Monoxide (Co) As A Starting Material Part 1. Interfacial Polycondensation Phosgene Process Chapter 5. Technological Aspects Of The Industrial Processes For Producing Aromatic Polycarbonates Using Carbon Monoxide (Co) As A Starting Material Part 2. Non-phosgene Process Chapter 6. General Aspect Of Non-Phosgene Polycarbonate Process From Co2 (Asahi Kasei Process) Chapter 7. Monomer Production Technology From Co2 (Asahi Kasei Process) Chapter 8. Melt Polymerization Technology Of Asahi Kasei Process Chapter 9. Excellent Features Of Polycarbonate Produced By Asahi Kasei Non-Phosgene Process Chapter 10. Economical Features Of Asahi Kasei Non-Phosgene Polycarbonate Process Chapter 11. Contribution Of Asahi Kasei Non-Phosgene Polycarbonate Process To Society Chapter 12. Other Approach 1 – Outline Of Chemical Fixation Of Co2 Into Polymer Chapter 13. Other Approach 2 – Development Of Non-Phosgene Mdi Process

16. Summary for Phosgene Polyurethane Synthesis
Elimination of phosgene from isocyanate synthesis
Methyl isocyanate synthesis on demand (DuPont)
Advances in pest management to eliminate carbamates
Challenge:
On demand production of other isocyanates
Create similar products synthetized from less harmful materials

17. General Toxicity Rules for Safer Substitutions
CO2 is less toxic than CO
Ethanol is less toxic than methanol
Aliphatic amines are less toxic than aromatic and nitro aromatic compaunds
Routs to amines through diols are less toxic than through nitriles
Higher MW substance is less toxic that low MW substance
Roots via carboxylic acid are less toxic than via nitro compounds
Solids give less problems than liquids

18. Replacements for HCN 1. Replacements in gold ore extraction
- Thiourea (can be reused)/ thiourea + Fe(III) sulfate in ionic liquid
- Chloride on activated carbon
2. Replacements in adipic acid synthesis
Renewable raw materials (petroselenic acid, cis-muconic acid

19. Elimination of Formaldehyde
Phenol-formaldehyde and urea-formaldehyde adhesives for the plywood and particle board

20. Elimination of Formaldehyde
Crease proofing resin for cotton
Being replaced by 1,2,3,4-butanetetracarboxylic acid and poly(maleic acid)