16 Amidocarbonylation Downloaded by UNIV OF MICHIGAN ANN ARBOR on February 18, 2015 | http://pubs.acs.org Publication Date: March 1, 1992 | doi: 10.1021/ba-1992-0230.ch016
Catalyst, Reaction Scope, and Industrial Application J. J . Lin and J. F. Knifton 1
Texaco Chemical Company, P . O . Box 15730, Austin, TX 78761
Amidocarbonylation, first discovered by Wakamatsu in 1971, is an underrated and underused technology in synthesis gas chemistry. In combination with hydroformylation, amidocarbonylation provides a versatile route to the synthesis ofα-amidocarboxylicacids from an olefin, acetamide, and CO-H . Our research focused on the application and extension of amidocarbonylation technology to the synthesis of a wide range of amidocarboxylic acids, including surface-active agents (C -C amido acids), specialty surfactants (sarcosinates), intermediates for sweeteners, food additives (glutamic acid), and chelating agents. Homogeneous cobalt- and rhodium-based catalysts, modified with sulfoxide and bidentate phosphine ligands, were tailored to the synthesis of each individual class of products. Processing studies (reaction rate, product selectivity, and catalyst stability) and economic assessments are discussed. 2
10
X J L M I D O C A R B O N YLATION,
16
the synthesis of xV-acyl-a-amino acids from al-
dehyde, carbon monoxide, and amide, was first reported by Wakamatsu et al. in 1971 (i). In 1979 Parnaud et al. (2) investigated the reaction mechanism, and in 1981 Stern (3) patented a process for making amido acids directly from olefins. By 1985, Ojima et al. (4) demonstrated that this technology can be extended to other substrates (including trifluoropropene, oxirane, and allyl alcohols) by the use of binary metal catalysts. Applications of amino acid derivatives in the areas of enhanced oil recovery (5), liquid detergents (6), and gas-scrubbing agents (7) have been reported. 'Current address: Shell Development Company, P.O. Box 1380, Houston, TX 77251
0065-2393/92/0230-0235S06.00/0 © 1992 American Chemical Society
In Homogeneous Transition Metal Catalyzed Reactions; Moser, W., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1992.
236
H O M O G E N E O U S TRANSITION
METAL CATALYZED
REACTIONS
Currently, most amino acids are obtained from natural sources or fer mentation. Amidocarbonylation can be considered a viable alternative to the conventional Strecker reaction, which uses highly toxic hydrogen cyanide and ammonia to make α-amino acids from aldehydes. Since 1983 we have been interested in amidocarbonylation technology for two reasons: (1) pro duction of specialty chemicals is an extension of our synthesis gas (syngas) research and (2) amidocarbonylation is a unique technique for constructing
Downloaded by UNIV OF MICHIGAN ANN ARBOR on February 18, 2015 | http://pubs.acs.org Publication Date: March 1, 1992 | doi: 10.1021/ba-1992-0230.ch016
two functionalities in a single step. Herein we report the use of amidocarbonylation technology for the synthesis of a wide range of amido acids, including surface-active agents (C -C 1 0
l f i
amido acids), specialty surfactants, intermediates for aspartame
sweeteners (β-phenylalanine and IV-acetylglycine), food additives (sodium monoglutamate),
and chelating agents (iminoacetic acid and polyamido
acids). Therefore, many products can be made by the same technology.
Amidocarhonylation IV-Acetylglycine.
iV-Acetylglycine, the simplest amido acid, was syn
thesized in 60% yield from paraformaldehyde, carbon monoxide, and acetamide by using octacarbonyldicobalt as the catalyst under 2900 psi C O - H
2
(3:1) at 120 °C in ethyl acetate solvent. The effect of ligands on reaction yield and catalyst recovery was studied. The addition of diphenyl sulfoxide or succinonitrile ligands to this catalyst system increased the yield of Nacetylglycine to 78% yield. In addition, catalyst recovery increased from 50% to 85% (on the basis of cobalt used). Similarly, addition of tributylphosphine promoted the reaction at lower pressure (800 psi). By comparison, the che lating tetramethylethylenediamine adversely affected the reaction. The ef fects of ligands on reaction yield and catalyst recovery are summarized in Table I (8).
L-Phenylalanine.
L-Phenylalanine is a key intermediate for aspar
tame sweetener, a methyl ester of the L-phenylalanine-L-aspartic acid dipeptide (see structure). Currently, L-phenylalanine is produced by tyrosine fermentation (by Genex and Searle). One proposed synthetic route is the oxidative carbonylation of styrene to form cinnamate ester and subsequent
NH,®
COOCH
3
aspartame (L-aspartic acid + L-phenylalanine)
In Homogeneous Transition Metal Catalyzed Reactions; Moser, W., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1992.
In Homogeneous Transition Metal Catalyzed Reactions; Moser, W., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1992.
3
6
2
8
CH
20 6 0 100 15
—
80 94 100 0 85
—
1
60 68 78 0 70 0
Yield of I (%)
( I I )
\
(I)
2
NHCOCH3
Molar Ratio
+
NHCOCH3 /
NHCOCH3
2 2 2 2 5 5
\
120 120 120 120 110 110
2
2900 2900 2900 2900 800 800
CH
3:1 3:1 3:1 3:1 8:1 8:1
>
CO-H,
Conditions"
2
"Paraformaldehyde (2.0 g), acetamide (5.9 g), Co (CO) (0.34 g), EtOAc (15-20 g). Tetramethylethylenediamine.
2
None Ph SO Succinonitrile TMEDA* n-Bu P None
Ligand
3
CH C0NH
Time (h)
•
Temperature CO
X
/
COOH
Pressure (psi)
2
(CH 0)
2
Co (C0)g
Table L N-Acerylglycine Synthesis and Catalyst Improvement
Downloaded by UNIV OF MICHIGAN ANN ARBOR on February 18, 2015 | http://pubs.acs.org Publication Date: March 1, 1992 | doi: 10.1021/ba-1992-0230.ch016
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80
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