Note: Descriptions are shown in the official language in which they were submitted.
-
WO 95/07882 2 1 7 0 4 8 7 PCT/US94/10138
SYNTHESIS OF AMIDO ACIDS FROM CAR~3OXYLIC ACID ESTERS A \ID
AMINO ACID SALTS
FIELD OF T~ INVENTION
The present invention relates to the chemical synthesis of amido acids, and their
conversion to amido acid phenyl ester sulfonates for use as bleach activators. This
conversion can be direct by reaction of the amido acids with phenol sulfonic acid
derivatives; or by the conversion of the amido acids to their phenyl ester form and
then the conversion of said amido phenyl esters into their sulfonated form; or by the
conversion of the amido acids to their anhydride and then reaction with sodium
phenol sulfonate to form the amido acid phenyl ester sulfonates.
BACKGROUND O~ THE INVENTION
The synthesis of ingredients for use in low unit cost consumer goods such as
laundry detergents, fabric softeners, hard surface cleansers, and the like, is of
considerable interest to m~nllfar.tllrers. Indeed, while formularies and patents are
filled with listings of prospective ingredients for use in such products, the reality is
that many such ingredients are simply too expensive for day-to-day use. This
expense is often due either to the cost of the raw materials used to make such
ingredients, or to the complex reaction and processing chemistly which is required in
their m~mlf~ch~re Accordingly, m~nl-f~ctllrers have conr~uc.ted a continuing search
for both inexpensive raw materials and simple reaction sequences which can produce
high performance, high value ingredients at the lowest possible cost.
The amido acids comprise one class of chemicals whose amido and carboxylate
functional groups suggest their use as surf~ct~nts (i.e., sarcosinates)~ fabric softeners.
~nti~t?ltiC agents and the like. Moreover, the amido acids constitute a basic raw
material for the amido phenyl ester sulfonate class of chemicals which can serve as
bleach activators in laundry detergents and other types of bleach-containin_ cleaning
compositions. Such activators have several desirable attributes such as excellent
bleaching performance with minim~l color damage on fabric dyes, good washing
m~nhine compatibility and a good odor profile in the wash. On the positive side, the
amido acids and their aforementioned derivatives are potentially obtainable frominexpensive raw materials. Unfortunately, the synthesis of certain amido acids is
somewhat complicated and can involve the use of solvents, with additional problems
associated with recycle streams and the like. Problems can also arise with the
formation of undesirable colored by-products. Moreover~ the conversion of the
WO 95/07882 PCT/US94110138
'2'~ 1 C~487
amido acids to their phenyl ester sulfonate form is not straightforward and can be
surprisingly problematic.
The present invention provides a simple method for the synthesis of amido
acids. It also provides four methods for converting amido acids into amido acid
phenyl ester sulfonates which are suitable for use as bleach activators in laundrv
detergents, and the like. The first method is a simple, one-step esterification of
amido acid with phenol to provide an amido acid phenyl ester which can
subsequently be reacted with SO3 and neutralized in conventional fashion to giveamido acid phenyl ester sulfonates. The second prepares the amido acid phenyl ester
by tran~esterification of ester derivatives of phenol followed by the conversion to the
amido acid ester sulfonates as described for the first method. The third method
involves tr~n.~sterification of ester derivatives of phenol sulfonic acid or salt
(typically sodium or potassium) with amido acid to provide amido acid phenyl ester
sulfonates directly. The fourth method involves making the anhydride of the amido
acid and reacting this anhydride with sodium phenolsulfonate to also produce amido
acid phenyl ester sulfonates directly.
The individual reaction sequences herein proceed in acceptable yields (typically60%, and higher) and, importantly, result in products with minimal discoloration. In
some cases, the reactions may be con~ cted without added solvents, i.e., the
re~ct~nt~ act as solvents. Hence, for many purposes the reaction products need not
be extensively purified which further improves the overall economics of the
processes.
BACKGRQUND ART
The boric acid-catalyzed esterification of certain phenols is described by W.
Lowrance, Jr., in Tetrahedron Letters No. 37 pp. 3453-3454 (1971). See Surfactant
Science Series~ Vol. 7, Part III. p581-617, for general syntheses of amido acids. A
process for preparing certain b~n7.~nçslllfonate salts appears in U.S. 5,153,541,
Amini and Dumas, October 6, 1992.
SUMMARY OF THE INVENTION
The present invention encompasses a method for preparin~ amido acids and
salts thereof of the formulae
ii . ~
R---C----N---R1 C~ OM
R2 o
(IA)
and
o
R--C N Rl SO3M
R2
WO 9_~7~&2 PCT/US94/10138
3 ~1 70~7
(IB)
wherein R and R2 are independently a C1 or higher hydrocarbyl substituents. Rl is
Cl-ClO hydrocarbylene substituent, and M is a cationic moiety selected from alkali
metal salts and hydrogen, by the steps of:
(a) reacting a carboxylic acid ester of the formula
o
R--C--OR3
Carboxylic Acid Ester
with an amino acid salt of the structure
o
HN- -R~- C - - OM
R2
Amino Acid Salt
or
~C--N-- (CH2)2SO3M
R2 , respectively.
wherein R, Rl, and R2 are as described before, and M is an alkali metal salt,
and
(b) optionally, neutralizing the amido acid salt formed by step (a) to form the
amido acid, whereby M is hydrogen in formulae IA and IB.
The p~ cr~l I ed method for p~ el~a~ g said amido acids is conducted at a
temperature from about 80C to about 200C. especially from about l '0(` tc ab~ ut
1 80C.
In one pl~Çellt;d embodiment the method herein employs an amino acid salt
selected from the salts of 6-aminocaproic acid, sarcosine, glycine, taurine, N-methyl
taurine, serine, isoserine, methionine, and proline. In a preferred aspect, the
carboxylic acid ester is a methyl or ethyl ester (R3 = methyl or ethyl) havin,~
substituent R as C6-C 17
In order to facilitate mixing of the re~ct~nt.s and ~ e reaction time, it isplefelled to conduct the reaction in an alcohol solvent which has a boiling point of at
least 100C. The presence of a basic catalyst such as sodium methoxide also
accelerates the reaction. The reaction proceeds in greater than 90% vield with amolar ratio of fatty methyl ester reactant to amino acid salt reactant to basic catalyst
of about 1:1:0.2.
The invention also encompasses a method for preparing amido acid phenyl
esters of the formula
R- C --N----Rt C-- OPh
Rz O
WO 95/07882 PCT/US94/10138
%~ 7 Q4~1 ~
(II)
wherein R, R I and R2 are as described herein before,
comprising reacting an amido acid having Formula (IA) above with phenol in
the presence of a strong catalyst and boric acid to produce the amido acid phenyl
esters of Formula (II).
In this method the strong acid (non-boric acid) catalyst is a member selected
from the group consisting of sulfuric acid~ methanesulfonic acid.
trifluorometll~n~slllfonic acid, tol~leneslllfonic acid, phosphonic acid and mixtures
thereof. Preferably, the mole ratio of boric acid to the strong acid catalyst is at least
about 1:1, more preferably at least about 1:3.6. Preferably, the mole ratio of amido
acid to strong acid catalyst is at least about 1:0.05 and more preferably about 1:0.25.
This esterification reaction is preferably conducted at a temperature in the range t;om
about 180C to about 210C, and is most preferably conducted without added
solvent.
The esterification herein is preferably conducted at a temperature of about 180-190C in the absence of solvent, with 98% sulfuric acid as the acidic catalyst, and at
a mole ratio of boric acid to sulfuric acid of at least about 1:3.6. Preferably, an
excess of phenol is used, typically a phenol:amido acid mole ratio of about 5:1 to
about 20: 1.
The invention also encomp~ses a method for preparing amido acid phenyl
esters of the Formula (II) comprising reacting an amido acid having Formula (IA)above with a phenyl ester of a lower molecular weight carboxylic acid moiety,
preferably phenyl acetate, in the presence of a basic catalyst. The basic catalvst can
be selected from the group consisting of carboxylate salts, carbonates, imidazole and
mixtures thereof. Preferably, the mole ratio of basic catalyst to amido acid is at least
about 0.001:1, more preferably at least about O.Ol:l. Preferably, the mole ratio of
amido acid to phenyl ester is at least about 1:1 and more preferably about 3.1. This
tr~n~esterification reaction is preferably conducted at a temperature in the range from
about 160C to about 210C, and is most preferably conducted without added
solvent.
As an overall proposition, the invention herein also provides a method for
preparing bleach activators comprising sulfonating and neutralizing an amido acid
phenyl ester of Formula (II) prepared according to the foregoing processes to
produce amido acid phenyl ester sulfonates of the formula:
R--C N Rl C--o ~ ~SO3M
(III)
WO 95A~7882 1~CT/U594/10138
wherein R, Rl and R2 are as described hereinbefore. the amido acid phenvl
ester sulfonate is predominantly para-substituted (as pictured) althouvh ortho-
substitution is acceptable, and M is a cationic moiety, preferably a mono- or divalent
metal salt (e.g.~ pot~.sinm~ sodium) or hydrogen, which for use of these compounds
as bleach activators should be sutst~rlti~lly free of transition metal ions (known to
cause instability of peroxy compounds).
The invention also encompasses a method for preparin~ amido acid phenyl ester
sulfonates of the Formula (III) above by reacting an amido acid of Formula (IA)
above with an ester derivative of phenol sulfonic acid or salt of the formula:
SO3M
OR3
wherein M is a cationic moiety as described herein before. and R3 is an acid
moiety, preferably a lower (C2-Cs) molecular weight carboxylic acid moiety such as
the most p,e~l,ed acetic acid moiety. When M is hydrogen, the addition of catalyst
is not required; when M is a metal salt, this transesterification reaction can utilize an
acid or base catalyst.
Reaction temperatures for this tr~n.cesterification reaction are at least about
150C, pr~r~,~bly from about 180C to about 220C, for reactions with acetoxy
benzene sulfonic acid sodium salt. Lower reaction temperatures, from about 140C`
to about 180C, are plere"ed for reactions with acetoxy benzene sulfonic acid.
The invention also provides a method for preparing amido acid phenyl ester
sulfonates of the Formula (III) above by reacting an amido acid of Formula (IA)
above with a lower (C4-Clo) molecular weight carboxylic acid anhydride (e.~.,
(R4C0)20, wherein each R4 is the same or di~e, ent C I -C4 hydrocarbyl
substituents), preferably acetic anhydride, to form the amido acid anhydride Theamido acid anhydride is then reacted with phenolsulfonate salt (preferably the sodium
salt) to form the desired amido acid phenyl ester sulfonates.
The amido acid anhydride is prepared by reactin~ amido acid with the lower
molecular weight carboxylic acid anhydride in a molar ratio ran~in~ from about 1:~
to about 5:1. Reaction temperatures are from about 70-1 10C with reaction times of
about 1-18 hr. Catalysts such as sodium acetate, sodium carbonate~ sodium
bicarbonate~ imi~l~701e~ or methanesulfonic acid can be used. At the end of the
WO 95/07882 PCT/US94/10138
a7 6
reaction, carboxylic acid and/or excess carboxylic acid anhydride. such as acetic acid
and/or excess acetic anhydride, are removed by distillation.
The crude amido acid anhydride mixture is then reacted with anhvdrous sodium
phenolsulfonate in a molar ratio of about l: l . Reaction temperatures are from about
100-200C with reaction times of about l-6 hr. Basic catalysts such as sodium
acetate or imidazole can be used. If the crude amido acid anhydride contains excess
amido acid, then solvent is not needed. If excess amido acid is not present in the
amido acid anhydride, solvents such as dimethylformamide, toluene, or xylenes can
be used.
All percentages, ratios and proportions herein are on a mole basis. unless
otherwise specified. All doc~lmPnt.~i cited are incorporated herein by reference DETAILED DESCRIPTION OF THl~ INVENTION
The reaction sequence (l) for the synthesis of the amido acids and reaction
sequence (2a) and (2b) for their conversion to the phenyl ester form are shown
below. Sequence (3) illustrates the conventional sulfonation step, which typicallv
inclllde~ base neutralization to prepare the salt form of the amido phenyl estersulfonate class of bleach activators. Sequences (4a), (4b), and 5 show alternative
methods for preparing the amido phenyl ester sulfonate directly from the amido acid
prepared by Sequence (1). The reaction sequences as illustrated employ octanoic
acid methyl ester and 6-aminocaproic acid sodium salt, but this is only by way of
illustration and not limitation, as will be seen hereinafter.
Sequence 1
N~ 1-butanol O
H, ) + NaOH pellets ~ H2N~~ ,ONa
Lactam Alll ,ocapruic AcidFatty Methyl Ester NaOMe
Sodium Salt ~ -MeOH
H O HCOOH H O
'`~`'U`OH ~ '`'~-'`~`~`ONa
-NaOOCH O
Amido acid Amido Acid Sodium Salt
Sequence 2a
PCTrUS94/10138
W O 95/07882
7 21 70487
H O OH H O
~~OH ~1 Acid Catalyst ~, ~~ ~' OPh
Amido Acid Phenol Amido Acid Phenyt Ester
~OPh
O
Carboxylic Acid Phenyl Ester
H O
`N' ~ . OPh
H b
Diamido Acid Phenyl Ester
Sequence 2b
~ N- ,OH ~ NaOAc catalyst ~N~ ^ ro`~
Sequence3
O 1)S0s ,-~-'~~^~'J~N ~ r ~
H O 2)Neutralization H O `SO3Na
Amido Acid Phenyl Ester Amido Acid Phenylestersulfonate
Sequence 4a
O SO3Na o
~N OH ~ ~ ~`H ~J`so31\1a
OAc
Sodium Acetoxybenzenesulfonate Amido Acid Phenylestersulfonate
SO3Na ~.
.1~ + AczO
OH
PCT/US94/10138
WO 95/07882
2~ 7 ~4~7
Sequence Ib
H O SO3H H O
OH + [~ ~ OPhSO3H
OAc
Amido AcidAcetoxybenzenesulfonate Amido Acid Phenylestersulfonate
OH OAc OH
Ac2o ~ t 3 g~ Acid or Base
SO3H Catalysis
Phenolsulfonic Acid Phenylacetate Phenol
S~qlJ~n~ 5
~,OH + AC20 H ~ N~ N
Amido Acid Anhydride
NaOAc catalyst
'I SO~Na
N ~ `1;~
The following is by way of illustration, and not limitation, of conditions,
equipment and the like, useful in Sequences 1, 2, 3, 4, and 5 of the instant process.
Sequence 1. The carboxylic acid ester reactant can be selected from alkyl
esters (plerel~bly methyl or ethyl) of straight chain aliphatic, branched chain aliphatic~
saturated or unsaturated, aromatic, heroaromatic, ethercarboxylic and cycloaliphatic
carboxylic acids. Nonlimitin~ examples include methyl or ethyl esters of the
following carboxylic acids: acetic, propionic, butyric, caprylic, caproic, nonanoic~
3,5,5-trimethylhexanoic, decanoic, lauric, myristic, palmitic~ stearic~ oleic. Iinoleic.
behenic, 2-methyl-~1ndec~noic, 2-butyl-octanoic, 2-ethyl-hexanoic~ alkyl- and
alkenylsuccinic, adipic, cyclohexyl, C8(EO),,CO,,H, benzoic. chloro-benzoic.
nitrobenzoic, naphthenic, abietic, nicotinic, 2-pyridine-carboxylic. terephthalic.
phthalic, and mixtures thereof.
The amino acid salt reactant in Sequence I can be, for example: the sodium
salts of amino acids derived from hydrolysis of 5-12 membered rin~ lactams such as
5-aminovaleric acid and 6-aminocaproic acid or sodium salts of sarcosine. ~lvcine.
taurine. N-methyl taurine~ serine. isoserine. methionine and proline and mixtures
W095/07882 2 1 7 0 4 8 ~ PCT/US94/1~)138
thereof. The sodium salts of the amino acids can be generated either by neutralizin~o
the amino acids with a sodium hydroxide solution and then drying or by neutralizina
with sodium methoxide (convenient for lab plepalalions since it does not introduce
water).
The reaction conditions in Sequence I are as follows Any air in the system
during lactam hydrolysis and amidation steps causes darkenin~J of the reaction
mixture. Also the presence of water during lactam hydrolysis and amidation
drastically reduces the yield of these steps. Consequently, an inert gas (nitro~en is
convenient) is sparged through the reaction mixture during these steps in Sequence 1.
Inert gases such as argon, or the like, can also be used. The objective is to provide a
nonoxidizing reaction system in order to minimi7e the formation of colored
co,,l~.,.;,~;..,l.~
Lactam hydrolysis is necessary if a lactam is used as the source of the amino
acid salt reactant. An alcohol solvent is used in which dry sodium hydroxide has at
least partial solubility. In order to complete the hydrolysis in a 2-8 hr reaction time,
the alcohol used must have a boiling point above 100C. The alcohol will also serve
as the solvent for the amide formation step. It is plefelled that the alcohol boiling
point be less than 200C, since it must be removed from the amido acid prior to
Sequence 2 or 4 and for economical reasons be easily recycled. I-Butanol is an
especially pl erel . ed solvent.
Lactam hydrolysis requires a molar ratio of sodium hydroxide to lactam of at
least 1:1~ preferably 1.05:1. The sodium methoxide catalyst to be used in the amide
forrnation step may be added during lactam hydrolysis, since alcohol solution orsuspension of amino acid salt reactant is used directly in the amide formation step.
The hydrolysis proceeds most readily when the amount of solvent used is the
miniml~m necessary to dissolve the sodium hydroxide.
Amidation requires that the amino acid salt reactant be at least partially miscible
in the carboxylic acid ester. In the case of the sodium salts of 6-aminocaproic acid.
glycine, or taurine, a solvent is necessary to achieve partial miscibility. In the case of
sarcosine sodium salt~ no solvent is necessary if the reaction is performed at 180-
200C
Reaction temperatures in the amidation step will typically be above about 80C
and below about 200C and are preferably in the range from about 1 10C to about180C. For low boiling carboxylic acid esters such as ethyl acetate, it mav be
~ppl op, iate to use a pressure vessel in order to achieve the desired reaction
temperature. Reaction times can vary, of course, dependina on the reactant ~olu~ s
~'~ 1 PCT/US94/10138
1()
being employed. However, as a general rule for reactions in the 100 mls size range~ a
reaction time in the range from about 0.5 hours to about 4 hours is sufficient
During the amidation step, the alcohol ori~in~ting from the carboxylic acid
ester (typically methanol) is distilled from the reaction. In order to accelerate the
reaction, some of the alcohol solvent (typically butanol) may also be removed so lon
as the reaction mixture is still easily stirred.
Reaction stoichiometry in the amidation step employs a molar ratio of amino
acid salt reactant to carboxylic acid ester to basic catalyst of about 1:1.05:0.2. The
basic catalyst is preferably sodium methoxide.
After the amidation step, to form the amido acid the amido acid salt must be
neutralized to the amido acid and the alcohol solvent removed. A variety of acids
(sulfuric, formic acids) can be used to neutralize the alcohol solution of the amido
acid salt so long as the salt of the neutralization acid is sparingly soluble in the
alcohol solvent. For example, acetic acid is not as p,er~"ed as formic acid because
sodium acetate is more soluble than sodium formate in methanol/butanol Formic
acid is convenient if l-butanol is the reaction solvent. Sodium formate is sparingly
soluble in l-butanol and precipitates. Amido acid is soluble in the butanol. Typically
a molar ratio of acid to amido acid salt of about 1:1 is used. Finally, butanol is
removed from the amido acid by r~i~till~tion and can be recycled.
Sequence 2a. The p~ epal ~ion of the phenyl esters of carboxylic acids, especially the
amido acids, is as follows. Useful carboxylic acid reac.t~nt~ in Sequence ' include all
of the amido acids prepared per Sequence 1. The phenol reactant includes phenol,itself, as well as alkyl substituted phenols such as cresols and phenol derivatives such
as phenolsulfonates.
The strong acid catalyst used in Sequence 2 can be any of the strong protonic
acid catalysts used in Sequence 1. Sulfuric acid (98%) is convenient. inexpensive and
l),ere"t:d. Under the process conditions the sulfuric acid sulfates the phenol i~/ .~'lll~.
so that the strong acid catalyst is at least partially the phenolsulfonic acid.
While not intended to be limiting by theory, it is believed that the mechanism of
ester formation involves the formation of a triphenol borate ester by a reaction of a
borate material with the phenolic material; followed by exchange of phenol for
carboxylic acid to form a carboxylic/boric anhydride species; followed by some
manner of phenol displacement of the borate ester from the carboxylic-boric
anhydride species; followed by exchange of water to form the borate species and
reform the triphenol borate active catalyst agent. Accordingly, any borate or boric
acid material, or precursor thereof, which results in the formation of a triphenol
borate ester with phenol or substituted phenols can be used herein Tvpical e~amples
WO 95/07882 2 1 7 0 4 8 7 PCT/US94/10138
.
Il
of such materials include boric acid, boric acid precursors boric acid esters. for
example, materials such as borax~ tributylborate, triphenylborate, and the like. A
wide variety of borate materials are available from standard~ commercial sourcesBoric acid is a convenient and inexpensive catalyst for use in Sequence ~
It is further hypothesi7ecl that the presence of the strong protic acids probably
plays at least three dirre,-e"~ roles in the esterification mechanism catalvsis of the
initial borate ester formation; catalysis of phenol displacement of the borate species;
and as a desiccant for water which is produced in the reaction
With regard to reaction conditions, in Sequence 2 any air in the system causes adrastic darkening of the reaction mixture, just as in Sequence l. Consequently~
nitrogen sparging or sparging with another inert gas in order to provide a
nonoxidizing condition is preferably used. Again, as in Sequence 1, it is preferred in
Sequence 2 to use an inert reaction vessel such as those made from glass, quartz.
stainless steel, or the like.
Reaction temperatures of at least 1 50C, preferably from about l 80C to about
200C, are plefelled, and reaction times are similar to those disclosed for .Seqllence
l, typically 2 to 4 hours. Water (which may be present in the starting materials) is
removed during the first 30 minlltes of the reaction by azeotropic distillation of
phenol/water. The presence of water is detrimental to the overall yield because it can
result in the hydrolysis of the amide linkage of the amido acids and/or amido acid
phenol esters.
It has been determined that excess phenol or substituted phenol is necessary to
drive the reaction to completion. Less excess phenol is viable if azeotropic
dietill~tion is carried out for the entire reaction time. Typically. about a ~ mole
excess of said phenol or substituted phenol is employed, preferably from about 8 to
about 12 mole excess. Based on the amido acid portion of one mole, the strong acid
catalyst proportion is at least about 0.01 mole, preferably from about 0.'~5 mole to
about 0.5 mole. The boric acid is used at levels from about O.Ol mole to about 0.07
moles, based on the amido acid reactant.
Following the esterification reaction, excess phenol is removed from the
reaction mixture by vacuum distillation or other suitable means, and can be recycled
The remaining reaction product consists of the desired amido acid phenol ester.
carboxylic acid phenyl ester and unreacted amido acid. This reaction product can be
purified prior to sulfonation. or can be sulfonated without further purification since
the cont~min~nt~ are compatable with many detergent compositions
Sequence 2b. Transesterification of a phenyl ester of a lower (C~-C~)
molecular weight carboxylic acid moiety, preferably phenyl acetate~ with amido acid
~ ~ 7 0 4 ~ 7 12 PCT/US~4/10138
in the presence of a basic catalyst provides amido acid phenyl ester in ~ood yield
The basic catalyst can be selected from the group consisting of carboxylate salts,
carbonates, imidazole and mixtures thereof. Preferably, the mole ratio of basic
catalyst to amido acid is at least about 0.001:1, more preferably at least about 0 01 l
Preferably, the mole ratio of amido acid to phenyl ester is at least about 1: 1 and more
preferably about 3:1. This tr~n.c~st~rification reaction is preferably conducte(i a~ a
temperature in the range from about 1 60C to about '' 1 0C, and is most preferably
con~ cted without added solvent.
Sequence 3 . Sulfonation of the amido acid phenol ester can be conducted usin~
sulfur trioxide, sulfur trioxide vapor, chlorosulfonic acid, sulfur trioxide complexes,
oleum, sulfamic acid, and the like, plus other typical sulfonating a~ents. Reaction can
be carried out without solvent, or, if desired, can be conducted in solvents such as
sulfur dioxide, methylene chloride, ethylene dichloride, carbon tetrachloride,
fiuorotrichlorom.oth~n~, and the like. It is ,olerelled to run the sulfonation reaction of
Sequence 3 without solvent. Of course, unsaturated materials should be avoided in
the reaction mixture, primarily due to color formation.
As in the case of Sequences I and 2, the sulfonation reaction of Sequence 3 is
highly acidic and inert reaction vessels are again used. Reactors can be of the
continuous film or continuous cascade types, for example. When sulfur trioxide is
used as the sulfonating reactant, it is preferably introduced in an inert ~as stream
(nitrogen or dry air) cont~inin~ 1-20% by weight sulfur trioxide. Reaction
temperatures are typically 20C to 200C with reaction times of from 5 to 180
minutes (based on I mole of amido acid phenyl ester being sulfonated). For a tvpical
run, the amido acid phenyl ester is present at a I mole level and this sulfonating agent
used at a 0.9-1.5 mole level. Product work-up involves neutralizin~ the crude
reaction mixture to pH 4-6 with base such as sodium bicarbonate, sodium acetate.sodium formate, or the like.
Sequence 4. Amido acid phenyl ester sulfonate can also be made by
tr~n~esterification of acetoxyben7~?nesll1fonic acid or its salt (typically sodium or
potassium) with amido acid. If acetoxyben7enesll1fonic acid sodium salt is used~ then
a 3-4 mol equivalent excess of amido acid is necessary to act as solvent If
acetoxybenzenesulfonic acid is used, then a 1.2 mol equivalent excess of amido acid
is sufficient. Either base or acid catalysis promotes the transesterification ofacetoxybenzenesulfonic acid sodium salt; sodium acetate or sulfuric acid are typicallv
used. Transesterification with acetoxybenzenesulfonic acid does not require a
catalyst.
WO 95/07882 2 1 7 0 4 8 7 PCT/US94/10138
13
A stream of inert gas is passed over the reaction so as remove acetic acid as itis formed and provide a nonoxidizing environment. As in Sequence 3~ inert reaction
vessels are p, ~re, I ed.
Reaction temperatures of at least about 150 C, preferably from about 180 C
to about 220 C, are necessary for transesterification with acetoxybenzenesulfonic
acid sodium salt. Lower reaction temperatures (from about 100 C to about 140 C)
are ple~lled when using acetoxyben7Pnes~llfonic acid because less side products are
formed. Reaction times are 1-4 hours for either tr~n.cestçrification.
Acetoxybenzenesulfonic acid sodium salt can be plepaled from reaction of
excess acetic anhydride with dry phenolsulfonic acid sidium salt. Acetic anhydride or
acetic acid can serve as a solvent. Acetoxybenzenesulfonic acid can be made fromreaction of acetic anhydride with dry phenolsulfonic acid. Alternatively, it can be
made from sulfonation of phenyl acetate with sulfur trioxide or chlorosulfonic acid
Following tr~n~esterification with acetoxybenzenesulfonic acid sodium salt, the
excess amido acid must be removed from product and recycled. This can be
achieved by grinding the reaction product into small particles and dissolving the
amido acid with a solvent. The solid amido acid phenyl ester sulfonate is then
collected by filtration. Several solvents are suitable: cold methanol, butanol at 60 C.
tolue~e and xylenes at 1 00C, octanoic acid. Product workup after
tr~n~est~rification with acetoxyben7~nes~1fonic acid involves neutralizing the crude
reaction mixture as in Sequence 3.
Sequence 5. Formation of the amido acid anhydride is accomplished by
reacting amido acid with acetic anhydride. Reaction temperatures between 70 and
120C are favored to avoid acylation of the amide nitrogen. The molar ratio of
amido acid to acetic anhydride is from 1:3 to 5: 1. If the molar ratio is 3: 1 and higher,
it is not necess~ry to add a solvent for the reaction with sodium phenolsult`onate
A~er a reaction time of 1-18 hr, acetic acid and/or acetic anhydride are distilled from
the reaction mixture to give the crude amido acid anhydride. Sodium
phenolsulfonate is then added in a 1:1 molar ratio to the amido acid anhydride and
the reaction is heated at from 100 - 200C for 1-18 hr. Toluene or xylenes can be
used as solvents for this reaction. At the end of the reaction, unreacted amido acid
can be removed from the amido acid phenyl ester sulfonate by washing with a hot
solvent (ie. toluene) which melts or dissolves the amido acid, but does not dissolve
the amido acid phenyl ester sulfonate.
It is to be understood that the overall process herein provide several advantages
over other processes. For example, with respect to the amido acids, the usual
synthesis of amido acids (ie. sarcosinate surfactants) employs the reaction of t`atty
WO 95/07882 PCT/US94/10138
~7a4~1 ~
14
acid chlorides with an amino acid in an aqueous alkaline medium There a
substantial cost advantages over the present development, inasmuch as fatty methyl
esters are less expensive starting materials than fatty acid chlorides. In the usual
synthesis, sodium chloride waste is generated, which is not a factor in the present
invention. Moreover, the process does not involve large amounts of water~ which
would have to be removed prior to Sequence 2.
With regard to the amido acid phenyl ester synthesis of Sequence '',
esterification of the amido acid can be achieved by forming the acid chloride of the
amido acid and subsequently reacting it with phenol or phenolsulfonate. The prior
art reaction has the same problems as those mentioned above for the amido acid
synthesis. While esterification of conventional carboxylic acids with phenols using
boric/sulfuric acid has been described in the Lowrance article, cited hereinabove, the
reaction conditions described by Lowrance fail to esterify amido acids in any
reasonable yields. For example, the present process employs much higher reactiontemperatures than those disclosed by Lowrance, said temperatures being achieved by
using phenol as the azeotroping agent. Moreover, much higher amounts of sulfuricacid catalyst are used herein, which promotes the desired reaction while reducin~, side
reactions.
In the prior art (e.g., European Patent Application No. 105,67,, published
April 18, 1984) of forming phenyl ester sulfonates, a fatty acid anhydride is formed
(from reaction with acetic anhydride) and then reacted with phenolsulfonic acid
sodium salt. It should be noted that reaction of amido acid with acetic anhvdrid~
under these conditions results not only in formation of amido acid anhydride, but also
in formation of imides which is unacceptable. Transesterification with
acetoxybenzenesulfonic acid or its salt avoids imide formation.
The overall processes herein comprising either Sequences l, 2a, and 3~
Sequences 1, 2b, and 3, Sequences I and 4, or Sequences l and S have several
advantages, including one or more of: low cost starting materials; minimum number
of reaction steps; good yields for each step; reasonable reaction times; no waste
by-products; ability to recycle starting materials; and no solids handlinc~ until the last
step.
The following Examples further illustrate the invention but are not intended to
be limiting thereof.
Analytical
GC Analysis Method. This method is applicable to the determination o~'the relative
content of octanoic acid, decanoic acid, octanoic acid phenyl ester. octanovl
caprolactam, 2-pyrrolidinone, octanoyl diamido acid~ phenylesters of Cg-C l o
PCT/US94/10138
WO 95/07882 2 1 7 0 4 ~ 7
15
amidocaproic acid, C8 amidobutyric acid, caprolactam, 6-aminocaproic acid. Cg-C l o
amidocaproic acid, and phenol, in reaction samples.
The components listed above are separated, after silylation, by temperature
programmed GC on a lSm DBI column. A hot (300C) split injector is used and
detection is by FID. GC area % is used to estimate content of components in a
sample. The materials containing active hydrogens are derivatized with BSTFA
cont~inin~ 1% TMCS.
Chemicals:
Reagents
Pyridine
N,O-bis (trimethylsilyl)trifluoro~cet~mide with 1% trimethylchlorosilane
Equipment:
Equipment Description Source
Hewlett Packard 5890 GC Hewlett Packard
HP7673 split injection
flame ionization detector
Column: 15m, DB-1, J&W Scientific
0.25mm rD, .25u
Procedure:
1. Standard Preparation:
(See sample p~epa.~ion below to make retention time standard solutions.)
2. Sample Preparation:
Weigh 5-10 mg sample into a GC vial~ add l .0 mL derivatization ~rade pyridine
and 0.6 mL BSTFA (w/1% TMCS), seal vial, and heat at 70C for 30 minutes.
3. Instrument Settin~s 4. Approximate Retention Times:
a) Split injection On Phenol 6.3
2-Pyrrolidinone 7.6
b) Split ratio About 30:1 Caprolactam l0.0 ( 185)*
c) Column flow ImL/min. Octanoic acid 10.3
d) Purge flow 0.5mL/min. Decanoic acid 13.6
e)Injectionvolume luL 6-aminocaproicacid 14.3, 17.9
(347)*
f) Injector temperature 300C Octanoic acid phenyl ester 16.4
Octanoyl amidobutyric acid 17.3
g) Inlet oven tracking Off Octanoyl caprolactam l 9 5 (~ 9)*
h) FID detector 330C Octanoyl amidocaproic acid ~3.'. '4 u
temperature (3~9)
WO 95/07882 PCT/US94/10138
~ 7 ~ 4~7
i) Oven initial 50C Decanoyl amidocaproic ".3. '6.'
temperature acid
j) Oven ramp rate 8.0C/min.Hexanoyl amidocaproic acid '5 7
phenyl ester
k)Ovenfinal 325C Octanoyl amidocaproic acid 276(333
temperature phenyl ester
1) Oven final hold time 4.63 min.Decanoyl amidocaproic acid 29.6, 30.5
phenyl ester
Octanoyl diamidocaproic 31.4~ 32.4
acid
*Molecular weight of GC component.
4. Calculation of Mole% Conversion: The GC relative area % for each
component derived from caprolactam is divided by its molecular weight or the
molecular weight of its trimethylsilyl derivative to give a relative mol%. The relative
mol% for all components derived from caprolactam are summed to ~give a total
relative mol%. Finally, each relative mol% is divided by the total relative mol% to
give mol% conversion. An analogous procedure is used to calculate mol%
conversion of amido acid to amido acid phenyl ester.
AMIDATION EXAMPLES I-IV
EXAMPLE I
Synthesis of C8-Amidocaproic Acid
Step A. Hydrolysis of Caprolactam - A three-neck, 2 L round bottom flask is
fitted with mechanical stirrer and condenser and heated with an oil bath. Throughout
all reactions, stirring and a static pressure of nitrogen is maintained Sodium
hydroxide pellets 98.5% (34.76 g, 0.856 mol), 25% sodium methoxide in methanol
(33.7 g, 0.156 mol), methanol (100 mL), and l-butanol (210 mL) are added to the
flask. The mixture is heated to reflux for about 20 min to dissolve the sodiull1hydroxide and then concentrated by rii~tilling away 130 mL of solvent. Caprolactam
99% (88.06 g, 0.78 mol) is added and the mixture refluxed for 3.5 hr. After 15 min,
the mixture becomes cloudy and foamy. After 1.5 hr, the reaction is clear After ~.5
hr, the reaction becomes solid. After 3.5 hr, I-butanol (60 mL) is added to solubilize
the reaction mixture. HNMR and TLC indicate ~90% yield of 6-aminocaproic acid
sodium salt.
Step B. Amidation of fatty methyl ester - The clear solution of 6-
aminocaproic acid sodium salt from Step A is allowed to cool until it starts to solidify
and then methyl caprylate 99% (130.91 g, 0.819 mol) is added. The mixture is
heated to reflux and it becomes clear after 2 min. After 9 min. the reaction mixture
Wo 9s/07882 2 PCT/US94/10138
17
becomes solid. The reaction is kept at reflux for a total of l hr Then methanol ~ ~()
mL) / l-butanol (500 mL) is added and the reaction mixture refluxed until most o~'
the solid is dispersed (about 10 min). HNMR and TLC indicate - 90% vield o~`
amido acid salt.
Step C. Neutralization of amido acid sodium salt - Formic acid 96% (50.35
g, 1.05 mol) is added to the slightly cooled dispersion of amido acid sodium salt trom
above. The mixture is refluxed for about lO min until only a fine white precipitate
(sodium forrnate) remains. The reaction mixture is allowed to cool to room
temperature and then suction filtered to remove sodium formate. The sodium
ffirmate precipitate is washed with l-butanol (200 mL). HNMR indicates that the
sodium formate contains a trace of amido acid. Butanol and methanol are removed
from the amido acid by vacuum rli~till~tion to give C8 amidocaproic acid ( l 72.~ g.
77% yield based on caprolactam).
EXAMPLE II
Synthesis of Oleyl Amide of Glycine Sodium Salt - A 500 mL, 3-neck. round
bottom flask is fitted with thermometer, Dean-Stark trap with condenser, mechanical
stirring, and a purge tube through which nitrogen is passed through the reactionmixture. The reaction vessel is charged with glycine (7.28 g, 0.097 mol), sodiummethoxide 25% in methanol (25.2 g, 0.116 mol), methanol (~0 mL), and propvlene
glycol (24 g). The reaction is refluxed l5 min to neutralize the glycine and thell
meth~nol is distilled off using the Dean-Stark trap. The reaction mixture is then
heated to 160C and methyl oleate 70% (43.2 g, 0.102 mol) is added. Reaction ij
kept at 160C for 1.5 hr during which methanol (7 mL) is collected in the Dean-Stark
trap. The reaction is allowed to cool, acetone (300 mL) is added~ and the mixture
cooled to 10C. The precipitate is collected by filtration, washed with cold acetone
(200 mL), and dried in oven at 60C to give the desired'product as a light yellow
solid (35.9 g).
EXAMPLE III
Synthesis of Oleyl Amide of Sarcosine Sodium Salt - A 500 mL, 3-neck.
round bottom flask is fitted with thermometer, Dean-Starl; trap with condenser,
mechanical stirring, and a purge tube through which nitrogen is passed through the
reaction mixture. The reaction vessel is charged with sarcosine (8.0 g, 0.09 mol)
sodium methoxide 25% in methanol (23.3 g, 0.108 mol), and methanol (80 mL). The
reaction is refluxed 15 rnin to neutralize the sarcosine and then methanol is distilled
off using the Dean-Stark trap. The reaction mixture is then heated to 16()(` and
methyl oleate 70% (40.0 g, 0.094 mol) is added. Reaction is l;ept aL l 8u ( lor 1 ~) hl
WO 95/07882 PCT/US94/10138
4al 18
during which methanol is collected in the Dean-Stark trap. The reaction is allowed
to cool and the desired product clear solid (49.8 g) is obtained.
E~AMPLE IV
Synthesis of Myristyl Amide of Taurine Sodium Salt - A 500 mL~ ,-neck~
round bottom flask is fitted with thermometer, Dean-Stark trap with condenser.
mechanical stirring, and a purge tube through which nitrogen is passed throu~h the
reaction mixture. The reaction vessel is charged with taurine (12.0 ~, 0.096 mol).
sodium methoxide 25% in methanol (24.9 g, 0.115 mol), m~thanol (150 mL), and
propylene glycol (34 g). The reaction is refluxed 15 min to neutralize the taurine and
then methanol is distilled offusing the Dean-Stark trap. The reaction mixture is then
heated to 160C and methyl myristate (24.7 g, 0.10 mol) is added. Reaction is kept
at 160C for 1.0 hr during which meth~nol (7 mL) is collected in the Dean-Stark
trap. The reaction is allowed to cool, acetone (300 mL) is added. and the mixture
cooled to 10C. The precipitate is collected by filtration, washed with cold acetone
(200 mL), and dried in oven at 60C to give the desired product as a white solid(33.0 g).
ESTERIFICATION EXAMPLES V-VIII
Synthesis of C8 Amidocaproic Acid Phenvl Ester - A l 00 mL, 3-neck. round
bottom flask is fitted with thermometer, Dean-Stark trap with condenser, magnetic
stir bar, and a purge tube through which nitrogen is passed through the reactionmixture. The reaction vessel is charged with C8 amido acid - made fiom (-8 aci(lchloride and aminocaproic acid - (l0 g, 0.037 mol, l mol equivalent), phenol. sulfuric
acid 98%, and boric acid. The reaction is kept at 180- l 95C for 4 hours usins~ a hi~Jh
temperature oil bath held at 205-210C, continuously sparging with nitrogen. Some
of the phenol is optionally removed with a Dean-Stark trap. After 4 hours reaction
time, the reaction mixture is analyzed by GC (see GC Analysis Method) to determine
% conversion of C8 amidocaproic acid to C8 amidocaproic acid phenyl ester (see
Table 6). Other products formed are caprolactam, octanoic acid, octanoic acid
phenyl ester, 6-aminocaproic acid. Reaction mixture color a~er 4 hours is noted
Table l. Esterification Results with C8 Amidocaproic Acid
Example # V Vl Vll
Phenol (mol equivalent) 20 5.7 15
Sulfuric acid (mol equivalent) 0.25 0.25 0.05
Boric acid (mol equivalent) 0.07 0.Q7 0.05
% phenol removed 50% removed50% removed no phenol
during first 40during firstremoved
min 3 () min
') 1 7'A ~f ~7 PCT/USg4/10138
WO 95/078~2 L I ~ U L~ ~ I
.
19
Reaction color after 4 hr orange orange yellow
GC Relative Area % for
Components
Caprolactam 1.28 10.16 7 41
Octanoic acid 0.12 4.22 1.87
6-aminocaproicacid 0.1 0.39 1 61
Octanoic acid phenyl ester 4.71 28.89 16.33
Octanoylcaprolactam 0.91 1.18 2.62
Octanoyl amido acid 0.58 8.9 46.39
Octanoyl amido acid phenyl ester 82.04 37.07 23.76
Octarloyl diamido acid 3.95 0
Octanoyl ~ mido acid phenyl ester 0 2.71 O
Mole % Conversion of Amido
Acid to Components
Caprolactam 3.7 15.4 11.4
6-aminocaproic acid 0.3 0 3 1 3
Octanoic acid phenyl ester 13.2 36.8 21.2
Octanoylcaprolactam 1.1 1.4 3.1
Octanoyl amido acid 1.2 7.6 40.2
Octanoyl amido acid phenyl ester 76.2 31.3 20.3
Octanoyl di~mido acid 3.8 0 0
Octanoic acid 0.4 5.5 2.
Octanoyl ~ mido acid phenyl ester 0 1.7 0
Table 1. continued
Example # VIII
Phenol (mol equivalent) 20
Sulfuric acid (mol equivalent)0.25
Boric acid (mol equivalent) 0.07
% phenol removed 50% removed
during first 40
min
Reaction color after 4 hr yellow
GC Relative Area % for
Components
Caprolactam 3.60
Octanoic acid 0.37
6-aminocaproic acid 0
PCT/US94/10138
wo 95/07882
481 ~ ~
2()
Octanoic acid phenyl ester 1~.54
Octanoylcaprolactam I .36
Octanoyl amido acid 5.95
Octanoyl amido acid phenyl ester 67.46
Octanoyl diamido acid 2.14
Mole % Conversion of Octanoyl
Amido Acid to Components
Caprolactam 6.3
6-aminocaproic acid 0
Octanoic acid phenyl ester 18.4
Octanoylcaprolactam 1.8
Octanoyl amido acid 5.8
Octanoyl amido acid phenyl ester 65.5
Octanoyl diamido acid 1.6
Octanoic acid 0.6
EXAMPLE IX
Scale-up Synthesis of C8 Amidocaproic Acid Phenyl Ester - A ~50 mL, 3-
neck, round bottom flask is fitted with thermometer, condenser, magnetic stir bar,
and a sparge tube through which nitrogen is passed through the reaction mixture.The reaction vessel is charged with C~ amidocaproic acid - product of Example 17 -
(20.8 g, 0.081 mol), phenol (152.3 g, 1.62 mol), sulfuric acid 98% (2.03 ~, 0.0'mol), and boric acid (0.35 g, 0.0057 mol). The reaction is kept at 200 C for 4
hours using a high temperature oil bath, continuously purging with nitro~en. Durin~
the first hour. of reaction time, 50 mL of phenol is removed via the Dean-Stark trap.
A~er 4 hours reaction time, the reaction mixture is analyzed by GC to determine %
conversion of C8 amidocaproic acid to C8 amidocaproic acid phenyl ester (see Table
5). Reaction mixture is brown after 4 hours. Phenol is removed by vacuum
di.~t~ tion (90-100C, 4.3 mm) to give the desired C8 amido acid phenyl ester as a
brown solution (31.6 g) with the analysis shown in Table 7.
Table 2. Esterification Results of Scale-up Reaction
GC Relative Area % for Components Reaction Product (at~er
Mixture distillation
Caprolactam 3.47 3.97
Octanoicacid 0 0
6-aminocaproic acid 0 0.29
Octanoic acid phenyl ester 8.33 5 79
Octanoylcaprolactam I .17 0
WO 95/1~7882 PCT/US94/10138
2 ~ 70487
21
Octanoyl amido acid 3.68 0
Octanoyl amido acid phenyl ester48.77 63.07
Octanoyl diarnido acid 10.08 11.10
Octanoyl diamido acid phenyl ester 2.07 8.22
Mole % Conversion of Caprolactam
to Components
Caprolactam 7 5 7 7
6-aminocaproic acid
Octanoicacidphenylester 15.1 8.6
Octanoylcaprolactam 2.0 0
Octanoyl amido acid 4.5
Octanoyl arnido acid phenyl ester 60.1 67.8
Octanoyl diamido acid 9.1 9.0
Octanoyl diamido acid phenyl ester 1.8 6.6
SULFONATION EXAMPLE X
Synthesis of C8 Arnidocaproic Acid Phenyl Ester Sulfonate - C8
Arnidocaproic acid phenyl ester (22.00 g, 0.0634 mol) is placed in 100 mL 2-neckround-bottom fitted with a glass tube reaching the bottom of the flask and a
condenser connected to a bubbler. The flask is heated to 50C in an oil bath to melt
the phenyl ester. Sulfur trioxide (5.0 g, 2.6 mL, 0.0634 mol) vapor diluted withnitrogen is added to the reaction over I hour through the glass tube. [The ~lass tube
is connected via Teflon tubing to another flask heated at 65C in which liquid sulfilr
trioxide is placed. Nitrogen is bubbled through the liquid sulfur trioxide to obtain the
gas mixture.] The reaction is then heated at 50C for an additional 30 minutes after
the sulfur trioxide addition. The reaction is allowed to cool to room temperature and
then poured into saturated aqueous sodium bicarbonate. The product precipitated as
a white solid and is collected by vacuum filtration. After drying, the product (17.7 g)
is obtained in 65% yield.
TRANSESTERIFICATION EXAMPLE XI
Synthesis of C 10 Amidocaproic Acid Phenyl Ester - Amido acid ( I .00 g,
0.0039 mol), phenyl acetate (1.59 g, 0.012 mol), and sodium acetate (0.032 g,
0.00039 mol) are placed in a 100 mL round-bottom flask fitted with condenser Thesolution is heated at 210 C for 0.5 hr under nitrogen. Then acetic acid and excess
phenyl acetate are removed by vacuum distillation with a Kugelrohr apparatus. The
product ( I .10 g) is obtained as a white solid which contains unreacted amido acid
and excess phenyl acetate. HNMR of crude reaction mixture indicates -75% vield
WO 95/07882 PCT/US94/10138
~,7G481 22
(by integration ratio of the 2.58 ppm resonance - CH_C(=O)OPh - to the . l
resonance - C(=O)NHC~
TRANSESTERIFICATION EXAMPLE XII
Synthesis of C 10 Amidocaproic Acid Phenyl Ester Sulfonate - Into a l 00 mL,
3 neck round bottom flask fitted with a nitrogen sparge tube~ magnetic stirrer, Dean-
Stark trap with condenser, and thermometer, is added C 10 amido acid (48.5 g, 0.17
mol), sodium acetoxyben7~n~sll1fonate (15 g, 0.057 mol), and sodium acetate (0.94
g, 0.114 mol). The reaction is kept at 200C for 3 hr using a high temperature oil
bath held at 205-210 C, continuously sparging with nitrogen Distillate (7 mL) is
collected in the Dean-Stark trap. The reaction is poured hot into a mortar and after
cooling is ground into a powder. HN~fR of crude reaction mixture indicates ~90%
yield (by integration ratio of the 2.58 ppm resonance - CH2C(=O)OPhSO3Na - to
the 3.16 resonance - C(=O)NHC__~ . The reaction mixture is recrystallized from
methanol (370 mL) to obtain a first crop (15.1 g) and a second crop (4.7 g) of
desired product (75% recryst~lli7ed yield based on sodium acetoxybenzenesulfonate).
ESTERIFICATION EXAMPLE XIII
Synthesis of C10 Amidocaproic Acid Phenvl Ester Sulfonate - Into a l00
mL, 3 neck round bottom flask fitted with a nitrogen sparge tube, m~gnetic stirrer,
Dean-Stark trap with condenser, and thermometer, is added C10 amido acid (3.5 g,0.0123 mol), acetic anhydride (0.46 g, 0.0045 mol), and meth~neslllfonic acid (0.002
g, 0.00002 mol). The reaction mixture is heated at 100C for 2 hr. to form the
amido acid anhydride. Then anhydrous sodium phenolsulfonate (0.80 g, 0.0041 mol)and sodium acetate (0.017 g, 0.0002 mol) is added and the reaction heated at 180C
for 1.5 hr. At the beginning the reaction is fluid, but at the end it is a thick paste
HNMR of crude reaction mixture indicates ~70% yield (by inteQration ratio of Ihe2.58 ppm resonance - CH~C(=O)OPh - to the 3.16 resonance - C(=O)NHCH
ESTER~FICATION EXAMPLE XIV
Synthesis of C8 Amidocaproic Acid Phenyl Ester Sulfonate - Into a 250 mL, 3 neckround bottom flask fitted with a nitrogen sparge tube, magnetic stirrer, Dean-Stark
trap with condenser, and thermometer, is added C8 amidocaproic acid (10.0 g. 0.039
mol), acetic anhydride (17.9 g, 0.175 mol), sodium acetate (0.16 g, 0.00'' mol), and
imidazole (0.13 g, 0.002 mol). The reaction mixture is heated at 110C for 3 hr with
a nitrogen sparge; 10 mL of distillate is collected in the Dean-Stark trap Then acetic
acid and excess acetic anhydride is removed by vacuum distillation to obtain amido
acid anhydride. The crude amido acid anhydride is dispersed in ether (60 mL)~
filtered, and dried to obtain nearly pure amido acid anhydride (indicated bv HNMR)
as a white solid (8.6 g).
W0 95/1~7882 ~ 1 7 o ~, 3 7 PCT/US94110138
.
23
Into a 100 mL, 3 neck round bottom flask fitted with a nitrogen sparge tube.
magnetic stirrer, condenser, and thermometer, is added a portion o~`the pure alniLlo
acid anhydride (3.5 g, 0.0071 mol), anhydrous sodium phenolsulfonate ( I . I I g,
0.0056 mol), sodium acetate (0.029 g, 0.0004 mol), and toluene ( 12 mL). The
reaction is refluxed 3 hr 1 80C. A small, homogeneous aliquot of the reaction
mixture is taken and evaporated for HNMR analysis. IINI~ indicates 7~% yield
based on sodium phenolsulfonate (by integration ratio of the 2.58 ppm resonance -
CH~C(=O)OPh - to the 3.16 resonance - C(=O)NHC~. Then additional toluene
(50 mL) is added, the reaction mixture filtered hot, and the precipitate dried to obtain
the desired product as a white solid (2.6 g) which is 54% pure by ~NMR (b~
integration ratio of the 2.58 ppm resonance - CH_C(=O)OPh - to the 3 .16 resonance
- C(=O)NHCH_~ . The r~m~in~er of the material is amido acid, sodium phenol
sulfonate, andacetoxybe~ P~ lfonate.
The following illustrates the use of the amido acids and bleach activators of this
invention in otherwise conventional consumer goods, but is not intended to be
limiting thereof.
EXAMPLE XV
A mild lubricious soap bar composition is prepared in conventional extrusion
appa,~ s, as follows. The bar resists dry cracking and wet smear.
In~redient Percent (wt.)
C16 18 fatty acid soap* 78.0
Amido acid** 6.0
NaCVKCI ( 1:1 wt.) 0. ~
c 1 2H33c(o)N-methyl~lu~mi~e 8 . O
Water and minors Balance
*1:1 (wt.) mixture of Na and K soaps
**Per Example I, above.
EXAMPLE XVI
A laundry bleaching system suitable for use alone or in admixture with a
conventional granular laundry detergent is as follows.
In~redient Percent (w
Sodium percarbonate 90.0
Bleach activator* 10.0
*Per Example XXVII, above.
The foregoing composition can be added to water at levels of 100 ppm, and
above, to provide a fabric bleaching action.
