January Deadline for 2005 PTC course - see below

PTC 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 S_N2 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 1970’s and has co-authored the best selling PTC books in 1978 and 1994.

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PTC Reaction of the Month
Asymmetric C-Alkylation

During 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

Phase-Transfer Catalyst of the Month
Benzyl Tributyl Ammonium Chloride

Advantages
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.
Disadvantages
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.

Meet 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 processes.

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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New PTC Service
PTC Option Go/No-Go Consultation

Purpose
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

Deliverables
PTC Organics will deliver a written confidential "PTC Option Opinion" for a specific organic reaction which will include: [1] a discussion of the factors anticipated to most likely influence the probability of success of the PTC option for your specific application, [2] an estimated probability of success for the specific application and [3] recommendation for go/no-go decision (does not include experimental program design).

Initiating the Project
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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Before 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.

Policy
The list of PTC Tip of the Month subscribers will not be sold, rented or transferred and will be used only by PTC Communications, Inc. and PTC Organics, Inc. to provide information related to Phase-Transfer Catalysis. PTC Communications, Inc. reserves the right to distribute the PTC Tip of the Month only to selected industrial chemists, engineers and managers.

PTC Tip of the Month #27 - December 2004
Copyright 2004 PTC Communications, Inc.

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