This patent describes the use of tetrabutylammonium hydroxide (TBA OH) as the catalyst for the aldol condensation between butyraldehyde and nonanal that achieves a high ratio of the C13 cross-aldol product relative to the self-condensation of the butyraldehyde.
One crucial factor for the success of this technology is to limit the amount of water in the system to under 10%, since the presence of water promotes the self-condensation of the butyraldehyde and greatly reduces the conversion of the more organophilic nonanal.
Typically, NaOH is used as the base catalyst for industrial aldol condensation but the use of NaOH usually requires the presence of more water that in turn promotes the undesired C8 self-condensation of the C4.
The use of TBA OH as the base with little water results in a majority of C13 product (cross-aldol condensation) and very high conversion of nonanal (92%-98%), even in the presence of 2 equivalents of butyraldehyde. In contrast, the use of aqueous NaOH without TBA OH results in very low conversion of nonanal at only 16% which of course results in very little C13 product.
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!).
