January Deadline for 2005 PTC course - see below
Tip of the Month
Supercritical Fluids & PTC
Professors Charles Liotta and Charles Eckert of Georgia Tech were awarded the 2004 Presidential Green Chemistry Challenge Award for integrating phase-transfer catalysis with supercritical fluids to achieve high reactivity and excellent separation using environmentally benign "tunable" solvent systems. One of the first landmark papers published by Liotta and Eckert using PTC and SCF CO2 was Brown, J. S.; Lesutis, H. P.; Lamb, D. R.; Bush, D.; Chandler, K.; West, B. L.; Liotta, C. L.; Eckert, C. A.; Schiraldi, D.; Hurley, J. S. Ind. Eng. Chem. Res. 1999, 38, 3622. For example, tetraheptylammonium bromide can be used as catalyst in SN2 reactions of cyanide or bromide with benzyl chloride using supercritical CO2 as the solvent which can be separated by simply reducing the pressure. The quat can sometimes act in its own third phase. Professor Liotta has been the leading PTC academic expert in the US since the early 1970ís and has co-authored the best selling PTC books in 1978 and 1994.
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Reaction of the Month
recent years, chiral salen-type transition metal complexes have emerged as good
catalysts for reactions such as oxidations and carbon-carbon bond formations.
Professor Michael North of Kings College in London. Prof. North uses the Cu (II)
salen complex shown below as catalyst (2 mole% loading) for asymmetric
C-alkylation of α-methyl imino esters
which after hydrolysis produces up to 90% enantiomeric excess for α,α-disubstituted
amino acids. Compared to Maruoka's chiral PTC, the Cu salen complex does not
provide as high an ee, however it may be worthwhile to explore the
cost-performance of such catalysts. [salen =
N,N'-bis(salicylaldehydo)ethylenediamine] Reference: http://www.ch.kcl.ac.uk/kclchem/staff/mno/res3.htm.
If you can't see the structures, click HERE
Catalyst of the Month
Benzyl Tributyl Ammonium Chloride
Lower cost alternative to tetrabutyl ammonium bromide (TBAB) with about the same number of carbons and about the same "accessibility" of the positive charge. Does not contain bromide, which can be an advantage if that needs to be avoided in a waste stream.
The benzyl group is labile and in addition to being less stable than TBAB, it can result in the formation of benzylated impurities. This is the major reason PTC Organics does not use benzyl tributyl ammonium chloride for high purity applications.
Reactivity Parameters (Contact PTC Organics for explanation)
Organophilicity is moderate with C# = 19, though the benzyl group behaves like a butyl group, so the "effective adjusted C#" may be closer to 16. Accessibility is medium-low with q-value = 0.89, though it also behaves closer to 1.
Availability, Samples and Quotes from Competitors
Request samples and quotes from: Delta Finochem, Dishman Pharmaceuticals & Chemicals, Lion Akzo, Nehachem, SACHEM (click on link) or click on www.phasetransfer.com/suppliers/bnztbac.htm
Other Phase-Transfer Catalysts:
PTC Supplier Directory: choose from a dozen suppliers & 80 PT catalysts and ask for free samples & quotes.
PTC Organics at Informex 2005:
PTC Organics will present an Enabling
Technologies poster entitled "10 Low Cost Processes Using Phase-Transfer
Catalysis" (click on www.informex.com/schedule/EnablingTechnologies/ptcorganics.htm).
Call Marc Halpern at +1 856-222-1146 to arrange a meeting to discuss how
phase-transfer catalysis can help your company achieve high-performance low-cost
Inexpensive patent attorney (United States) familiar with Phase-Transfer Catalysis, organic chemistry and biochemistry. Contact Mannie Morgenstern by E-mail or at telephone 818-788-5531 (California).
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PTC Option Go/No-Go Consultation
Provide a quick and cost-effective key decision aid during initial project planning, whether to pursue evaluation of phase-transfer catalysis as an option to achieve success or breakthrough performance for an organic reaction/process, consisting of uniquely qualified expert opinion and supported by 28 years of PTC experience and documented evidence.
Benefit & When To Use
Can be crucial to achieve highly effective R&D for organic chemical reactions/processes during process improvement, route selection, overcome challenging selectivity requirements, new process development, process retrofit for breakthrough performance and process optimization
PTC Organics will deliver a written confidential "PTC Option Opinion" for a specific organic reaction which will include:  a discussion of the factors anticipated to most likely influence the probability of success of the PTC option for your specific application,  an estimated probability of success for the specific application and  recommendation for go/no-go decision (does not include experimental program design).
To initiate project or obtain attractive pricing for 2005 budget planning, contact Marc Halpern at tel +1 856-222-1146, fax: +1 856-222-1124 or E-mail.
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performing any PTC reactions read this important message
Organic chemical reactions are inherently dangerous. Moreover, phase-transfer catalysis may provide rate and other enhancements which can intensify associated hazards. Under no circumstances should anyone perform any procedure on any scale based in whole or in part on any of the contents of this information provided here before thoroughly establishing safe operating procedures and performing a full and competent hazardous operations analysis with the participation of qualified technical personal trained in chemical, engineering, safety, industrial hygiene and environmental disciplines and sciences.
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PTC Tip of the Month #27 - December 2004
Copyright 2004 PTC Communications, Inc.
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