The process described in Allemand; P. (Cambrios Film Solutions Corporation) US Patent 11,020,802, 01-Jun-2021, is not a phase-transfer catalysis process but it is interesting because of the use of tetrabutylammonium chloride (TBAC) to reproducibly produce silver nanowires from silver nitrate when the absence of TBAC resulted in nanoparticles that were not nanowires.
The presence of 1 mole% tetrabutylammonium chloride (TBAC) was able to selectively and reproducibly convert silver nitrate into a silver nanowire on a 50 g scale, instead of producing a mixture of silver nanoparticles of various structures. The solvent and “reducing agent” (Ag [1] to Ag[0]) was ethylene glycol (3000 mL). One equivalent of PVP (polyvinyl pyrrolidone) served as a plastic flexible sheet upon which the silver is deposited. The PVP was dispersed in 1 L of ethylene glycol with a high shear mixture prior to the addition to the reaction flask. The mixture was heated to 140 C for 30 minutes. The length of the silver nanowires was 14 +/- 8 micrometers and the width was 83 +/- 22 nanometers.
We would appreciate input from our readers as to how ethylene glycol serves as a reducing agent for the ionic silver to silver metal.
About Marc Halpern
Dr. Halpern is founder and president of PTC Organics, Inc., the only company dedicated exclusively to developing low-cost high-performance green chemistry processes for the manufacture of organic chemicals using Phase Transfer Catalysis. Dr. Halpern has innovated PTC breakthroughs for pharmaceuticals, agrochemicals, petrochemicals, monomers, polymers, flavors & fragrances, dyes & pigments and solvents. Dr. Halpern has provided PTC services on-site at more than 260 industrial process R&D departments in 37 countries and has helped chemical companies save > $200 million. Dr. Halpern co-authored five books including the best-selling “Phase-Transfer Catalysis: Fundamentals, Applications and Industrial Perspectives” and has presented the 2-day course “Practical Phase-Transfer Catalysis” at 50 locations in the US, Europe and Asia.
Dr. Halpern founded the journal “Industrial Phase-Transfer Catalysis” and “The PTC Tip of the Month” enjoyed by 2,100 qualified subscribers, now beyond 130 issues. In 2014, Dr. Halpern is celebrating his 30th year in the chemical industry, including serving as a process chemist at Dow Chemical, a supervisor of process chemistry at ICI, Director of R&D at Sybron Chemicals and founder and president of PTC Organics Inc. (15 years) and PTC Communications Inc. (20 years). Dr. Halpern also co-founded PTC Interface Inc. in 1989 and PTC Value Recovery Inc. in 1999. His academic breakthroughs include the PTC pKa Guidelines, the q-value for quat accessibility and he has achieved industrial PTC breakthroughs for a dozen strong base reactions as well as esterifications, transesterifications, epoxidations and chloromethylations plus contributed to more than 100 other industrial PTC process development projects.
Dr. Halpern has dedicated his adult life to his family and to phase-transfer catalysis (in that order!).
