 |
Description  |
|
|
FIELD OF THE INVENTION
The present invention relates to high-sudsing detergent compositions which
are especially useful in hand dishwashing operations.
BACKGROUND OF THE INVENTION
The formulation of effective detergent compositions presents a considerable
challenge. Effective compositions are required to remove a variety of
soils and stains from diverse substrates. In particular, the removal of
greasy/oily soils quickly and efficiently can be problematic. For example,
the removal of greasy food residues from dishware in hand dishwashing
operations has become a particular challenge to the formulator. Modern
dishwashing compositions are, in the main, formulated as aqueous liquids;
accordingly, water-stable ingredients must be used. Moreover, such
compositions come into prolonged contact with skin; therefore, they must
be mild. Yet, mildness is difficult to achieve in an effective dishwashing
product, since products which remove grease from dishware may also tend to
remove the natural skin oils from the user's hands.
Various means have been suggested to enhance the grease and oil removal
performance of detergent compositions. Grease-cutting nonionic surfactants
have been employed, but some of these may be irritating to biological
membranes. Some suggestions have been made to use nonconventional
detergent surfactants in liquid compositions. Indeed, while a review of
the literature would seem to indicate that a wide selection of surfactants
is available to the detergent manufacturer, the reality is that many such
materials are specialty chemicals which are not suitable in low unit cost
items such as home-use detergent compositions. The fact remains that most
home-use detergents still comprise one or more of the conventional
ethoxylated nonionic and sulfated or sulfonated anionic surfactants,
presumably due to economic considerations.
The challenge to the detergent manufacturer seeking improved grease/oil
removal has been increased by various environmental factors. For example,
some nonbiodegradable ingredients have fallen into disfavor. Effective
phosphate builders have been banned by legislation in many countries.
Moreover, many surfactants are often available only from nonrenewable
resources such as petrochemicals. Accordingly, the detergent formulator is
quite limited in the selection of surfactants which are effective
cleaners, biodegradable and, to the extent possible, available from
renewable resources such as natural fats and oils, rather than
petrochemicals.
Considerable attention has lately been directed to nonionic surfactants
which can be prepared using mainly renewable resources, such as fatty
esters and sugars. One such class of surfactants includes the polyhydroxy
fatty acid amides. Moreover, the combination of such nonionic surfactants
with conventional anionic surfactants such as the alkyl sulfates, alkyl
benzene sulfonates, alkyl ether sulfates, and the like has also been
studied. Indeed, substantial success in the formulation of detergent
compositions has recently been achieved using the N-alkyl polyhydroxy
fatty acid amide surfactants. However, even these superior surfactants do
suffer from some drawbacks. For example, their solubility is not as high
as might be desired for optimal formulations. At high concentrations in
water they can be difficult to handle and pump, so additives must be
employed in manufacturing plants to control their viscosity. While quite
compatible with anionic suffactants, their compatibility can be diminished
substantially in the presence of water hardness cations. And, of course,
there is always the objective to find new surfactants which lower
interfacial tensions to an even greater degree than the N-alkyl
polyhydroxy fatty acid amides in order to increase cleaning performance.
It has now been determined that the N-alkoxy polyhydroxy fatty acid amide
surfactants surprisingly differ from their counterpart N-alkyl polyhydroxy
fatty acid amide surfactants in several important and unexpected ways
which are of considerable benefit to detergent formulators. The
alkoxy-substituted polyhydroxy fatty acid amide compounds herein
substantially reduce interfacial tensions, and thus provide for high
cleaning performance in detergent compositions, even at low wash
temperatures. The compounds herein exhibit more rapid dissolution in water
than the corresponding N-alkyl polyhydroxy fatty acid amide surfactants,
even at low temperatures (5.degree.-30.degree. C.). The high solubility of
the compounds herein allows them to be formulated as modern concentrated
detergent compositions. The compounds herein can be easily prepared as low
viscosity, pumpable solutions (or melts) at concentrations as high as
70-100%, which allows them to be easily handled in the manufacturing
plant. Moreover, the high solubility of the compounds herein makes them
more compatible with calcium and magnesium cations, even in relatively
concentrated compositions.
While it can thus be seen that the N-alkoxy polyhydroxy fatty acid amides
provide substantial benefits, in the main they do tend to exhibit somewhat
lower sudsing than their N-alkyl counterpart suffactants. However, users
of the so-called "light-duty liquid" hand dishwashing compositions tend to
equate product performance with suds height and persistence. Accordingly,
modestly sudsing hand dishwashing compositions, while perhaps effective
for their intended use, may be rejected by consumers based on their
sub-optimal sudsing profile.
Succinctly stated, the invention herein is based on the discovery that use
of specially selected "soap" materials can substantially enhance the
grease and oil removal properties of detergent compositions which contain
N-alkoxy polyhydroxy fatty acid amides. While not intending to be limited
by theory, it appears that the inclusion of such soap materials into the
present compositions substantially enhances their ability to rapidly lower
the interfacial tension of aqueous washing liquors with greasy and oily
soils. This substantial reduction of interfacial tension leads to what
might be termed "spontaneous emulsification" of greasy and oily soils,
thereby speeding removal from soiled surfaces and inhibiting the
redeposition of the soils onto substrates. This phenomenon is particularly
noteworthy in the case of hand dishwashing operations with greasy
dishware.
It has further been determined that the use of common linear soaps does not
provide optimum high sudsing, as is desired by the users of such
compositions for hand dishwashing. Indeed, linear soaps are often used to
diminish suds levels in certain European fabric laundering detergents;
accordingly, the use of conventional linear soaps in the current
compositions is sub-optimal, inasmuch as sudsing can suffer. Moreover,
some soaps tend to provide their best grease cutting performance at pH's
in the alkaline range, whereas it is much more desirable to have hand
dishwashing compositions formulated at near-neutrality.
By the present invention it has been determined that certain soaps, e.g.,
secondary alkyl carboxylates, not only provide a desired additional
lowering of interfacial tension, with its attendant increase in grease
removal performance, but also, and importantly, allow the formulation of
reasonably high sudsing liquid compositions which contain the aforesaid
desirable N-alkoxy- polyhydroxy fatty acid amide surfactants, and which
are stable and homogeneous. The inclusion of calcium ions in such
compositions still further enhances the lowering of interfacial tension,
and thus still further enhances grease removal performance. Moreover, the
sudsing of such compositions can be increased even further by the addition
of magnesium ions. These special benefits can be achieved at neutral pH,
which enhances mildness and avoids the need for costly buffering
chemicals. The overall unexpected improvements in performance and
aesthetic qualities, especially sudsing, are described in more detail
hereinafter.
BACKGROUND ART
Japanese Kokai HEI 3[1991]-246265 Osamu Tachizawa, U.S. Pat. Nos.
5,194,639, 5,174,927 and 5,188,769 and WO 9,206,171, 9,206,151, 9,206,150
and 9,205,764 relate to various polyhydroxy fatty acid amide surfactants
and uses thereof.
SUMMARY OF THE INVENTION
The present invention relates to detergent compositions with high sudsing
characteristics, comprising:
(a) at least about 1%, preferably from about 5% to about 55%, by weight of
an amide nonionic surfactant of the formula
##STR1##
wherein R is a C.sub.7 -C.sub.17, preferably C.sub.11 -C.sub.13,
hydrocarbyl moiety, R.sup.1 is a C.sub.2 -C.sub.4, preferably C.sub.2
-C.sub.3, hydrocarbyl moiety, R.sup.2 is a C.sub.1 -C.sub.3 hydrocarbyl or
oxy-hydrocarbyl moiety, most preferably methyl, and Z is a polyhydroxy
hydrocarbyl unit having a linear chain with at least two, preferably at
least three, hydroxyls directly connected to the chain; and
(b) at least about 1%, preferably from about 5% to about 35%, by weight of
a secondary soap.
In a preferred mode, the compositions are those wherein substituent Z of
nonionic surfactant (a) is derived from a reducing sugar, especially a
reducing sugar which is a member selected from the group consisting of
glucose, fructose, maltose, xylose and mixtures thereof
For high sudsing R, R.sup.1 and R.sup.2 on surfactant (a), R is preferably
7-13, R.sup.1 is preferably ethylene or propylene (ethylene compounds tend
to be higher sudsing than propylene) and R.sup.2 is preferably methyl. For
best cleaning, R is preferably C.sub.11-C.sub.13.
Preferred secondary soaps (b) include members selected from the group
consisting of secondary carboxyl materials of the formulae:
(i) R.sup.3 H(R.sup.4)COOM, wherein R.sup.3 and R.sup.4 are each
hydrocarbyl or hydrocarbylene units with the sum of R.sup.3 and R.sup.4
being in the range from about 7 to about 16 carbon atoms and M is H or a
water solubilizing cation;
(ii) R.sup.5 R.sup.6 COOM wherein R.sup.5 is C.sub.7 -C.sub.10 alkyl or
alkenyl, R.sup.6 is a hydrocarbyl ring structure and M is H or a
water-solubilizing cation; and
(iii) CH.sub.3 (CHR.sup.7).sub.k --(CH.sub.2).sub.m --(CHR.sup.7).sub.n
--CH(COOM)--(CHR.sup.7).sub.o --(CH.sub.2).sub.p --(CHR.sup.7).sub.q
--CH.sub.3 wherein each R.sup.7 is C.sub.1 -C.sub.4 alkyl, wherein k, n,
o, and q are integers in the range of 0-2 and m and p are integers in the
range of 0.8, and wherein the total number of carbon atoms is about 10 to
about 18, and wherein M is H or a water-solubilizing cation.
Highly preferred examples of said secondary soaps include the water-soluble
salt of secondary carboxyl materials which are members selected from the
group consisting of 2-methyl-1-undecanoic acid, 2-ethyl-1-decanoic acid,
2-propyl-1-nonanoic acid, 2-butyl-1-otanoic acid, 2-pentyl-1-heptanoic
acid, and mixtures thereof.
The compositions herein will optionally, but preferably, additionally
comprise at least about 1% by weight of a sulfated or sulfonated anionic
surfactant.
Especially high sudsing, high grease removal versions of the compositions
herein may also comprise at least about 1% by weight of an additional
surfactant which is a member selected from the group consisting of alkoxy
carboxylate, amine oxide, betaine and sultaine surfactants, and mixtures
thereof. Such surfactants may be used alone, or in combination with
sulfated or sulfonated surfactants.
In yet another mode, the compositions herein will additionally comprise at
least about 0.05% by weight of calcium ions, magnesium ions, or mixtures
thereof, to still further enhance grease removal and high sudsing
performance.
The invention also encompasses a method for hand cleaning of dishware
(including eating utensils, cooking utensils and the like) comprising
contacting said dishware with an aqueous medium containing at least about
100 ppm, preferably 200 ppm-15,000 ppm, of the aforesaid compositions,
preferably with agitation. The invention also encompasses a method for
cleaning fabrics, especially hand-washing, by agitating said fabrics in
the foregoing manner.
All percentages, ratios and proportions herein are by weight, unless
otherwise specified. All documents cited are incorporated herein by
reference.
DETAILED DESCRIPTION OF THE INVENTION
The N-alkoxy and N-aryloxy polyhydroxy fatty acid amide surfactants used in
the practice of this invention are quite different from traditional
ethoxylated nonionics, due to the use of a linear polyhydroxy chain as the
hydrophilic group instead of the ethoxylation chain. Conventional
ethoxylated nonionic surfactants have cloud points with the less
hydrophilic ether linkages. They become less soluble, more surface active
and better performing as temperature increases, due to thermally induced
randomness of the ethoxylation chain. When the temperature gets lower,
ethoxylated nonionics become more soluble by forming micelles at very low
o concentration and are less surface active, and lower performing,
especially when washing time is short.
In contrast, the polyhydroxy fatty acid amide surfactants have polyhydroxyl
groups which are strongly hydrated and do not exhibit cloud point
behavior. It has been discovered that they exhibit Krafft point behavior
with increasing temperature and thus higher solubility at elevated
temperatures. They also have critical micelle concentrations similar to
anionic surfactants, and it has been surprisingly discovered that they
clean like anionics.
Moreover, the polyhydroxy fatty acid amides herein are different from the
alkyl polyglycosides (APG) which comprise another class of polyhydroxyl
nonionic surfactants. While not intending to be limited by theory, it is
believed that the difference is in the linear polyhydroxyl chain of the
polyhydroxy fatty acid amides vs. the cyclic APG chain which prevents
close packing at interfaces for effective cleaning.
With respect to the N-alkoxy and N-aryloxy polyhydroxy fatty acid amides,
such surfactants have now been found to have a much wider temperature
usage profile than their N-alkyl counterparts, and they require no or
little cosurfactants for solubility at temperatures as low as 5.degree. C.
Such surfactants also provide easier processing due to their lower melting
points. It has now further been discovered that these surfactants are
biodegradable.
As is well-known to formulators, most laundry detergents are formulated
with mainly anionic surfactants, with nonionics sometimes being used for
grease/oil removal. Since it is well known that nonionic surfactants are
far better for enzymes, polymers, soil suspension and skin mildness, it
would be preferred that laundry detergents use more nonionic surfactants.
Unfortunately, traditional nonionics do not clean well enough in cooler
water with short washing times.
It has now also been discovered that the N-alkoxy and N-aryloxy polyhydroxy
fatty acid amide surfactants herein provide additional benefits over
conventional nonionics, as follows:
a. Much enhanced stability and effectiveness of new enzymes, like cellulase
and lipase, and improved performance of soil release polymers;
b. Much less dye bleeding from colored fabrics, with less dye transfer onto
whites;
c. Better water hardness tolerance;
d. Better greasy soil suspension with less redeposition onto fabrics;
e. The ability to incorporate higher levels of surfactants not only into
Heavy Duty Liquid Detergents (HDL's), but also into Heavy Duty Granules
(HDG's) with the new solid surfactants herein; and
f. The ability to formulate stable, high performance "High Nonionic/Low
Anionic" HDL and HDG compositions.
N-Alkoxy Polyhydroxy Fatty Acid Amides
The N-alkoxy polyhydroxy fatty acid amide surfactants used herein comprise
amides of the formula:
##STR2##
wherein: R is C.sub.7 -C.sub.17 hydrocarbyl, including straight-chain
(preferred), branched-chain alkyl and alkenyl, as well as substituted
alkyl and alkenyl, e.g., 12-hydroxyoleic, or mixtures thereof; R.sup.l is
a linear or branched C.sub.2 -C.sub.4 hydrocarbyl, preferably --CH.sub.2
CH.sub.2 --, --CH.sub.2 CH.sub.2 CH.sub.2 -- and R.sup.2 is a linear or
branched C.sub.1 -C.sub.3 hydrocarbyl or oxy-hydrocarbyl; and Z is a
polyhydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at
least 2 (in the case of glyceraldehyde) or at least 3 hydroxyls (in the
case of other reducing sugars) directly connected to the chain, or an
alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Z
preferably will be derived from a reducing sugar in a reductive amination
reaction; more preferably Z is a glycityl moiety. Suitable reducing sugars
include glucose, fructose, maltose, lactose, galactose, mannose, and
xylose, as well as glyceraldehyde. As raw materials, high dextrose corn
syrup, high fructose corn syrup, and high maltose corn syrup can be
utilized as well as the individual sugars listed above. These corn syrups
may yield a mix of sugar components for Z. It should be understood that it
is by no means intended to exclude other suitable raw materials. Z
preferably will be selected from the group consisting of --CH.sub.2
--(CHOH).sub.n --CH.sub.2 OH, --CH(CH.sub.2 OH)--(CHOH).sub.n-1 13
CH.sub.2 OH, --CH.sub.2 --(CHOH).sub.2 (CHOR')(CHOH)--CH.sub.2 OH, where n
is an integer from 1 to 5, inclusive, and R' is H or a cyclic mono- or
poly- saccharide, and alkoxylated derivatives thereof. Most preferred are
glycityls wherein n is 4, particularly --CH.sub.2 --(CHOH).sub.4
--CH.sub.2 OH.
In compounds of the above formula, nonlimiting examples of the amine
substituent group --R.sup.1 --O--R.sup.2 can be, for example:
2-methoxyethyl-, 3-methoxypropyl-, 2-ethoxyethyl-, 3-ethoxypropyl-,
2-methoxypropyl, 2-isopropoxyethyl-, 3-isopropoxypropyl-,
tetrahydrofurfuryl-, 3-[2-methoxyethoxy]propyl-, and CH.sub.3 O--CH.sub.2
CH(CH.sub.3)--.
R--CO--N< can be, for example, cocamide, lauramide, oleamide, myristamide,
capricamide, ricinolamide, etc.
While the synthesis of N-alkoxy polyhydroxy fatty acid amides can
prospectively be conducted using various processes, contamination with
cyclized by-products and other colored materials may be problematic. As an
overall proposition, the synthesis method for these surfactants comprises
reacting the appropriate N-alkoxy or N-aryloxy-substituted aminopolyols
with, preferably, fatty acid methyl esters either with or without a
solvent using an alkoxide catalyst (e.g., sodium methoxide or the sodium
salts of glycerin or propylene glycol) at temperatures of about 85.degree.
C. to provide products having desirable low levels (preferably, less than
about 10%) of cyclized or ester amide by-products and also with improved
color and improved color stability, e.g., Gardner Colors below about 4,
preferably between 0 and 2. If desired, any unreacted N-alkoxy or
N-aryloxy amino polyol remaining in the product can be acylated with an
acid anhydride, e.g., acetic anhydride, maleic anhydride, or the like, at
50.degree. C.-85.degree. C., in water to minimize the overall level of
such residual amines in the product. Residual sources of straight-chain
primary fatty acids, which can suppress suds, can be depleted by reaction
with, for example, monoethanolamine at 50.degree. C.-85.degree. C.
If desired, the water solubility of the solid N-alkoxy polyhydroxy fatty
acid amide surfactants herein can be enhanced by quick cooling from a
melt. While not intending to be limited by theory, it appears that such
quick cooling re-solidifies the melt into a metastable solid which is more
soluble in water than the pure crystalline form of the N-alkoxy
polyhydroxy fatty acid amide. Such quick cooling can be accomplished by
any convenient means, such as by use of chilled (0.degree. C.-10.degree.
C.) rollers, by casting the melt onto a chilled surface such as a chilled
steel plate, by means of refrigerant coils immersed in the melt, or the
like.
By "cyclized by-products" herein is meant the undesirable reaction
by-products of the primary reaction wherein it appears that the multiple
hydroxyl groups in the polyhydroxy fatty acid amides can form ring
structures. It will be appreciated by those skilled in the chemical arts
that the preparation of the polyhydroxy fatty acid amides herein using the
di- and higher saccharides such as maltose will result in the formation of
polyhydroxy fatty acid amides wherein linear substituent Z (which contains
multiple hydroxy substituents) is naturally "capped" by a polyhydroxy ring
structure. Such materials are not cyclized by-products, as defined herein.
Usage levels of the aforesaid N-alkoxy- or N-aryloxy- polyhydroxy fatty
acid amides herein typically range from about 5% to about 55%, preferably
from about 8% to about 20%, by weight of the compositions herein.
The following illustrates the syntheses in more detail.
EXAMPLE I
Preparation of N-(2-methoxyethyl)glucamine
N-(2-methoxyethyl)glucosylamine (sugar adduct) is prepared starting with
1728.26 g of 50 wt. % 2-methoxyethylamine in water (11.5 moles, 1.1 mole
equivalent of 2-methoxyethylamine) placed under an N.sub.2 blanket at
10.degree. C. 2768.57 grams of 50 wt. % glucose in water (10.46 moles, 1
mole equivalent of glucose), which is degassed with N.sub.2, is added
slowly, with mixing, to the methoxyethylamine solution keeping the
temperature below 10.degree. C. The solution is mixed for about 40 minutes
after glucose addition is complete. It can be used immediately or stored
0.degree. C.-5.degree. C. for several days.
About 278 g (.about.15 wt. % based on amount of glucose used) of Raney Ni
(Activated Metals & Chemicals, Inc. product A-5000) is loaded into a 2
gallon reactor (316 stainless steel baffled autoclave with DISPERSIMAX
hollow shaft multi-blade impeller) with 4L of water. The reactor is
heated, with stirring, to 130.degree. C. at about 1500 psig hydrogen for
30 minutes. The reactor is then cooled to room temperature and the water
removed to 10% of the reactor volume under hydrogen pressure using an
internal dip tube.
The reactor is vented and the sugar adduct is loaded into the reactor at
ambient hydrogen pressure. The reactor is then purged twice with hydrogen.
Stirring is begun, the reactor is heated to 50.degree. C., pressurized to
about 1200 psig hydrogen and these conditions are held for about 2 hours.
The temperature is then raised to 60.degree. C. for 10 minutes, 70.degree.
C. for 5 minutes, 80.degree. C. for 5 minutes, 90.degree. C. for 10
minutes, and finally 100.degree. C. for 25 minutes.
The reactor is then cooled to 50.degree. C. and the reaction solution is
removed from the reactor under hydrogen pressure via an internal dip tube
and through a filter in closed communication with the reactor. Filtering
product under hydrogen pressure allows removal of any nickel particles
without nickel dissolution.
Solid N-(2-methoxyethyl)glucamine is recovered by evaporation of water and
excess 2-methoxyethylamine. The product purity is approximately 90% by
G.C. Sorbitol is the major impurity at about 10%. The
N-(2-methoxyethyl)glucamine can be used as is or purified to greater than
99% by recrystallization from methanol.
EXAMPLE II
Preparation of C.sub.12 -N-(2-Methoxyethyl)glucamide
N-(2-methoxyethyl)glucamine, 1195 g (5.0 mole; prepared according to
Example I) is melted at 135.degree. C. under nitrogen. A vacuum is pulled
to 30 inches (762 mm) Hg for 15 minutes to remove gases and moisture.
Propylene glycol, 21.1 g (0.28 mole) and fatty acid methyl ester (Procter
& Gamble CE 1295 methyl ester) 1097 (5.1 mole) are added to the preheated
amine. Immediately following, 25% sodium methoxide, 54 g (0.25 mole) is
added in halves.
Reactants weight: 2367.1 g
Theoretical MeOH generated:
(5.0.times.32)+(0.75.times.54)+(0.24.times.32)=208.5 g
Theory product: FW 422 2110 g 5.0 mole
The reaction mixture is homogeneous within 2 minutes of adding the
catalyst. It is cooled with warm H.sub.2 O to 85.degree. C. and allowed to
reflux in a 5-liter, 4-neck round bottom flask equipped with a heating
mantle, Trubore stirrer with Teflon paddle, gas inlet and outlet,
Thermowatch, condenser, and air drive motor. When catalyst is added,
time=0. At 60 minutes, a GC sample is taken and a vacuum of 7 inches (178
mm) Hg is started to remove methanol. At 120 minutes, another GC sample is
taken and the vacuum has been increased to 10 inches (254 mm) Hg. At 180
minutes, another GC sample is taken and the vacuum has been increased to
16 inches (406 nun) Hg. After 180 minutes at 85.degree. C., the remaining
weight of methanol in the reaction is 4.1% based on the following
calculation: 2251 g current reaction wt.--(2367.1 g reactants wt.--208.5 g
theoretical MeOH)/2251 g=4.1% MeOH remaining in the reaction. After 180
minutes, the reaction is bottled and allowed to solidify at least
overnight to yield the desired product.
EXAMPLE III
Preparation of N-(3-methoxypropyl)glucamine
About 300 g (about 15 wt. % based on amount of glucose used) of Raney Ni
(Activated Metals & Chemicals, Inc. product A-5000 or A-5200) is contained
in a 2 gallon reactor (316 stainless steel baffled autoclave with
DISPERSIMAX hollow shaft multi-blade impeller) pressurized to about 300
psig with hydrogen at room temperature. The nickel bed is covered with
water taking up about 10% of the reactor volume.
1764.8 g (19.8 moles, 1.78 mole equivalent) of 3-methoxypropylamine (99%)
is maintained in a separate reservoir which is in closed communication
with the reactor. The reservoir is pressurized to about 100 psig with
nitrogen. 4000 g of 50 wt. % glucose in water (11.1 moles, 1 mole
equivalent of glucose) is maintained in a second separate reservoir which
is also in closed communication with the reactor and is also pressurized
to about 100 psig with nitrogen.
The 3-methoxypropylamine is loaded into the reactor from the reservoir
using a high pressure pump. Once all the 3-methoxypropylamine is loaded
into the reactor, stirring is begun and the reactor heated to 60.degree.
C. and pressurized to about 800 psig hydrogen. The reactor is stirred at
60.degree. C. and about 800 psig hydrogen for about 1 hour.
The glucose solution is then loaded into the reactor from the reservoir
using a high pressure pump similar to the amine pump above. However, the
pumping rate on the glucose pump can be varied and on this particular run,
it is set to load the glucose in about 1 hour. Once all the glucose has
been loaded into the reactor, the pressure is boosted to about 1500 psig
hydrogen and the temperature maintained at 60.degree. C. for about 1 hour.
The temperature is then raised to 70.degree. C. for 10 minutes, 80.degree.
C. for 5 minutes, 90.degree. C. for 5 minutes, and finally 100.degree. C.
for 15 minutes.
The reactor is then cooled to 60.degree. C. and the reaction solution is
removed from the reactor under hydrogen pressure via an internal dip tube
and through a filter in closed communication with the reactor. Filtering
under hydrogen pressure allows removal of any nickel particles without
nickel dissolution.
Solid N-(3-methoxypropyl)glucamine is recovered by evaporation of water and
excess 3-methoxypropylamine. The product purity is approximately 90% by
G.C. Sorbitol is the major impurity at about 3%. The
N-(3-methoxypropyl)glucamine can be used as is or purified to greater than
99% by recrystallization from methanol.
EXAMPLE IV
Preparation of C.sub.12 -N-(3-Methoxypropyl)glucamide
N-(3-methoxypropyl)glucamine, 1265 g (5.0 mole prepared according to
Example III) is melted at 140.degree. C. under nitrogen. A vacuum is
pulled to 25 inches (635 mm) Hg for 10 minutes to remove gases and
moisture. Propylene glycol, 109 g (1.43 mole) and CE 1295 methyl ester,
1097 (5.1 mole) are added to the preheated amine. Immediately following,
25% sodium methoxide, 54 g (0.25 mole) is added in halves.
Reactants weight: 2525 g
Theoretical MeOH generated:
(5.0.times.32)+(0.75.times.54)+(0.24.times.32)=208.5 g
Theory product: FW 436 2180 g 5.0 mole
The reaction mixture is homogeneous within 1 minute of adding the catalyst.
It is cooled with warm H.sub.2 O to 85.degree. C. and allowed to reflux in
a 5-liter, 4-neck round bottom flask equipped with a heating mantle,
Trubore stirrer with Teflon paddle, gas inlet and outlet, Thermowatch,
condenser, and air drive motor. When catalyst is added, time=0. At 60
minutes, a GC sample is taken and a vacuum of 7 inches (178 mm) Hg is
started to remove methanol. At 120 minutes, another GC sample is taken and
the vacuum has been increased to 12 inches (305 mm) Hg. At 180 minutes,
another GC sample is taken and the vacuum has been increased to 20 inches
(508 mm) Hg. After 180 minutes at 85.degree. C., the remaining weight of
methanol in the reaction is 2.9% based on the following calculation: 2386
g current reaction wt.--(2525 g reactants wt.--208.5 g theoretical
MeOH)/2386 g=2.9% MeOH remaining in the reaction. After 180 minutes, the
reaction is bottled and allowed to solidify at least overnight to yield
the desired product.
The foregoing reaction can be conducted usin | | |
