Note: Descriptions are shown in the official language in which they were submitted.
2 1 2 ~
HOECHST AKTIENGESELLSCHAFT HOE 93~F 918 Dr.GL-nu
Werk Gendorf
: ''
Process for the continuous preparation of polyhydroxy
fatty amides from N-alkylpolyhydroxyamines and alkyl
esters of fatty acids
Description
The invention relates to a pr~cess for the continuou~
preparation of polyhydroxy-fatty amides by reaction of N-
alkylpolyhydroxyamines with alkyl esters of fatty acids
in the presence of basic catalystsO
Polyhydroxy-fatty amides are valuable surface-active
compounds which are usable in many ways. Thus, for
example, they can be used as such or in a mixture:with
: anionic, cationic and/or nonionic surfactants as cleaning
agents, detergents, textile treatment compositions and
the like, that is in the form of solid products (for
example as powders, grains or granules), solutions,
dispersions, emulsions, pastes and the like. Since
polyhydroxy-fatty amides are also readily biodegradable
and can be prepared from renewable raw materials, they
have achieved greater Lmportance recently.
~20 The polyhydroxy-fatty amides in question are generally
:~ compounds of the formula R-CO-NR'-Z, in which R is a
hydrocarbon radical having about 5 to 30 carbon atoms,
preferably 8 to 18 carbon atoms, R~ is hydrogen, alkyl or
hydroxyalkyl having up to prefera~ly 6 carbon atoms and
: 25 Z is a linear polyhydroxyhydrocarbon radical having at
least three O~ groups, which can also be alkoxylated,
preferably a sugar alcohol radical. The preferred
polyhydroxy-fatty amides therefore correspond to the
formula below
2 ~ & L :~
- 2 -
Rl -N-CO--R2
I
fH2
(CHOH)n
CH2OH
in which R1 is a short-chain al]kyl or hydroxyl, R2 is a
fatty alkyl and n is preferably 3 or 4. The compounds
having n = 4, which are particularly preferred, are
termed glycamides and, in the case of glucose, are termed
hexose radical glucamides.
:The preparation of polyhydroxy-fatty amides is generally
carried out by reacting an N-alkylpolyhydroxy2mine (for
ex~mple N-alkylglucamine) with an alkyl ester of a fatty
: 10 acid in the prese~ce of basic compounds as catalystO The
reaction equation below with N-methylglucamine and methyl
la-lrate is intended to illustrate this in more detail:
C~3-N--~ + C11H23COCH3 , CH3-I-CO-C11}I23 ~ CH3
1 ~2 CH2
(C~O~) 4 (CBO~) 4
CH20H 1R20H
Such a process, for example, is described in the publica-
::~tions WO 92/06071, WO 92/06072, WO 92/06073, WO g2/08687
~` 15 and WO 93/03004.
:
According to the known processes for the preparation ofpolyhydroxy-fatty amides, the N-alkylglucamine and the
: alkyl ester of the fatty acid are reacted in a molar
ratio of essentially 1:1 in the prese.nce of a basic
cataly~t selected from the group comprising the alkali
metal alkoxides and alkali metal hydroxides at a
temperature below 135C (cf. e.g. WO 92/06073, pa~e 10,
~ ~ 2 '~
- 3 ~
lines 3 to 12~. In detail, the procedure is carried out
in such a way that the secondary glucamine, the alkyl
ester o~ the fatty acid, the basic catalyst compound and
a solvent are mixed together and the mixture is refluxed
until the desired degree of convexsion, whereupon the
fatty acid glucamide is isolated rom the reaction
product, if ne~essary with vacuum treatment (cf. e.g. WO
92/06073, Examples I to V). This process delivers a
relatively high conversion rate of the N-alkylpoly-
hydroxyamine used and the resulting N-methylglucamide is
also relatively pure, but, inter alia, it exhibits the
disadvantages o discontinuous procedures. Although in
the publications mentioned reference is made to the fact
that the process described can also be carried out
continuously, nothing further is stated~ in particular
with respect to apparatus setup, procedure, reaction
conditions and the like (cf. e.g. WO 92~06073, page 10,
lines 3 to 12).
The present invention now provides a continuous process
for the preparation of polyhydroxy-fatty amides. Starting
from C1 to C4 alkyl esters of fatty acid~, preferably from
methyl esters of fatty acids, a high degree of conversion
of the N-alkylpolyhydroxyamine used is to be achieved and
the resulting polyhydroxy-fatty amide is to be very pure,
that is it is to contain the particularly undesirable by-
products, i.e. cyclic polyhydroxy compounds, only in a
very small amount.
The process according to the invention for the continuous
preparation of polyhydroxy-fatty amides by reaction of N-
alkylpolyhydroxyamine and C1 to C4 alkyl ester of fattyacid in the presence of basic catalysts comprises con-
tinuously carrying out the reaction in at least two
stirred tanks arranged in a cascade and during this
carrying out the procedure in such a way that (in the
steady state~
a) in the first stirred tank a temperature of 6 0 to
120C, preferably 65 to 95C, is maintained and a
~ ~ 2 i~
,~ - 4 -
residence time is maintained (with retention of the Cl
to C4 alcohol present) such that a single-phase liquid
reaction mixture is obtained,
b) the single-phase liquid reaction mixture entering into
the second and further stirred tanks is held in each
case at a temperature of 60 to 100C, preferably 65 to
90C, and for a residence time such that in ea~h tank
a higher conversion rate in each case of N-alkyl-
polyhydroxyamine to polyhydroxy-fatty amide i6
obtained, C, to C4 alcohol present in the second
stirred tank and in the further stirred tanks being
distilled off under vacuum, and that
c) the polyhydroxy-fatty amide i6 isolated from the
reaction mixture leaving the last stirred tank.
The process according to the invention is preferably
carried out in two or three stirred tanks arranged in a
cascade. When the procedure is carried out in two stirred
tanks arranged in a cascade, it is preferably carried out
in such a way that (i~ the steady state)
a) the N-alkylpolyhydroxyamine~ the Cl to C4 alkyl ester
of the fatty acid in an amount of 1 to 1~5 mol,
preferably 1 to 1.1 mol, per mole of N-alkyl-
polyhydroxyamine and an alkali metal alkoxide or an
alkali metal hydroxide or a mixture thereof as basic
catalyst in an amount of 0.01 to 0.15 mol, preferably
0.05 to 0.1 molr per mole of N-alkylpolyhydroxyamine
and in the foxm of a 5 to 50% strength by weight,
preferably 20 to 40% strength by weight, methanolic
solution are continuously and simultaneously fed to
the first stirred tankr and in the tank a temperature
of 60 to 120~C, preferably 65 to 95Cr is maintained
and a residence time is maintained (with retention of
the C1 to C4 alcohol present) such that a single-phase
liquid reaction mixture is obtainedr
b) the single-phase liquid reaction mixture leaving the
first stirred tank and entering the second stirred
tank is kept in the second stirred tank at a tempera-
ture of 60 to 100Cr preferably 65 to 90Cr and under
21 ~ ~ 6'~ ~
, 5
vacuum, generally a vacuum of 5 to 150 mbar, prefer-
ably 10 to 50 mbar, and for a residence time such that
80 to 98 mol% of the N-alkylpolyhydroxyamine, prefer-
ably 85 to 95 mol%, are reacted, essentially all of
the C, to C4 alcohol present being distilled off, and
that
c) the polyhydroxy-fatty amide is isolated from the
reaction mixture leaving the second reaction tank.
According to another preferred embodiment in two stirred
tanks arranged in a cascade, the procedure is carried out
in such a way that in a first step (a1), the N~alkyl-
polyhydroxyamine is reacted with alkali metal alkoxide or
alkali metal hydroxide or with a mixture thereof in an
amount of 0.01 to 0.15 mol, preferably 0~05 to 0 1 mol,
per mole of N-alkylpolyhydroxyamine to prepare an essen-
tially anhydrous mixture essentially comprising N-alkyl-
polyhydroxyamine and the alkali metal salt of N-alkyl-
polyhydroxyamine formed and functioning as catalyst. This
mixture and alkyl ester of fatty acid in an amou~t of 1
20 to 1.5 mol, preferably 1 to 1.1 mol, per mole of the
N-alkylpolyhydroxyamine used to prepare the mixture are
then continuously and simultaneously fed to the first
stirred tank. The reaction in the first and second tanks
is then continued a~ described above.
When the process a~cording to the invention is carried
out in three stirred tanks arranged in a cascade, the
procedure is preferably carried out in such a way that
(in the steady state)
a) the N-alkylpolyhydroxyamine, the C1 to C4 alkyl ester
of the fatty acid in an amount of 1 to 1.5 mol,
preferably 1 to 1.1 mol, per mole of ~-alkyl-
polyhydroxyamine and an alkali metal alkoxide or an
alkali metal hydroxide or a mixture thereof as basic
catalyst in an amount of 0.01 to 0.15 mol, preferably
0.05 to 0.1 mol, per mole of N-alkylpolyhydroxyamine
and in the form of a S to 50% strength by weight,
preferably 20 to ~0% strength by weight, methanolic
, . , . - .- - . ..... ..
2~ 2'~L~4~
- 6 -
solution are continuously and simultaneously fed to
the first stirred tank, and in the tank a temperature
of 60 to 120C, preferably 65 to 95~C, is maintained
and a residence time is maintained (with retention of
the C1 to C4 alcohol present) such that a single-phass
liquid reaction mixture is obtained,
b) the single-phase liguid rPacti~n mixture leaving the
first stirred tank and entering the second stirred
tank is kept in the second stirred tank at a tempera-
ture of 60 to 100C, preferably 65 to 90C, and under
~acuum, generally a vacuum of 50 to 600 mbar, prefer-
ably 100 to 500 mbar, and for a residence time such
that 80 to 95 mol% of the N-alkylpolyhydroxyamine,
preferably 85 to 93 mol%, are reacted, the C1 to C4
alcohol present being distilled off down to a residual
amount of 0.1 to 20% by weight, preferably 0.5 .to 5%
by weight, based on solid product,
c) the single-phase liquid reaction mixture leaving the
second stirred tank and entering the third stirred
tank is kept in the third stirred tank at a tempera-
ture of 60 to 100C, preferably 65 to 90DC, and under
vacuum, generally a vacuum of 5 to 100 mbar, prefer-
ably 10 to 50 mbar, and for a residence time such that
93 to 99 mol% of the N-alkylpolyhydroxyamine, prefer-
ably 95 to 98 mol%, are reacted, essentially all of
the Cl to C4 alcohol present being distilled off, and
that
d) the polyhydroxy-fatty amide is isolated from the
reaction mixture leaving the third stirred tank.
.
The embodiment described above, in which an essentially
anhydrous mixture of essentially N-alkylpolyhydroxy-
amine and alkali metal salt of N-alkylpolyhydroxyamine
: functioning as catalyst is first prepared, is also a
further preferred process variant in the case of three
stirred tanks.
Since it is the aim of the process according to the
invention to keep as low as possible a temperature even
2 .12 7 ~
in the first stirred tank and constantly to have present
a single-phase liquid reaction mixture (a hom~geneous
phase or clear solution) (that is that still unreacted N-
alkylpolyhydroxyamine is present completely dissolved),
it can be necessary under some circumstances to introduce
further alcohol (methanol) as solvent additionally to the
alcohol liberated by the amidat:ion reaction. This amount
of additional alcohol which is fed to the first, and
frequently also the second stirred tank is in total
generally 0.5 to 20 mol, preferably 1 to 10 mol, per mole
of the N-alkylpolyhydroxyamine fed to the first tank.
The mixture described of N-alkylpolyhydroxyamine and an
alkali metal salt thereof in a catalytic amount is
preferably fed to the first stirred tank in the form of
a flowing melt at about 125 to 135DC. The preparation of
the mixture, in detail, is preferably carried out in a
manner such that the N-alkylpolyhydroxyamine and the
alkali metal compound are each used in the form of a 10
to 60% strength by weight, preferably 15 to 50% strength
by weight, aqueous solution (the N-alkylpolyhydroxy-
amine, because of the type of its preparation, generally
arises in the form of the said solutions), the two
solutions are mixed together, preferably at room tempera-
ture, and the aqueous mixture (total solution) is dried
by removing the water. The solvent water is preferably
removed until only at most 0.5% by weight of water is
still present, preferably at most 0.2 to 0.3% ~y weight,
based on the dry (dehydrated) mixture. The dehydration is
preferably achieved by distilling off the water under
vacuum from the said aqueous total solution at about 90
to 135C. The dehydration can be carried out with the aid
o~ conventional thin-film evaporators, falling film
evaporators or stripping apparatuses. It is assumed that
the mixture obtained after the removal of water essenti-
ally comprises, as the main constituent, the N-alkyl-
polyhydroxyamine used and alkali metal salt, which has
been formed, of N-alkylpol~vhydroxyamine, in which case
still other ~urther basic ~alkaline) alkali metal com-
~ : ~12 ~8~
pounds can be present, likewise acting as catalyst, such
as unreacted alkali metal starting compound and/or
modifications thereof, for example alkali metal oxideO
This product (mixture) is solid at room temperature, is
a more or less liquid melt at 115 to 135C and generally
only contains the abovementioned residual amount of water
of at most 0.5% by~weight, preferably at most 0.2 to 0.3%
by weight, based on the weight of the product.
It has proved to be advantageous if a viscosity lowering
ayent is introduced in the first or second stirred tank
or in both, preferably only in the second. Such agents
are preferably ethylene glycol, propylene glycol or C8 to
Cl8 fatty alcohols, or ethoxylates thereof having 1 to 5
ethylene oxide units, ethylene glycol, propylene glycol
or a mixture thereof being preferred. The amount can bevaried in broad ranges. It is generally 1 to 50?~ by
weight, preferably 2 to 30% by weight, based on solid
product.
The initiation of the continuous reaction according to
the invention, that is the preparation of a single-phase
liquid start mixture in the first stirred tank, can be
carried out in diverse ways. ThUs, the ester of the fatty
acid can be introduced, heated to reaction temperature
and the alkali metal compound and the N-alkylpolyhydroxy-
amine and, if required, methanol can be introduced intothe heated ester, whereupon the mixture is kept at
reaction temperature (without removal of the solvent)
until the sought-after single-phase liquid reaction
mixture is obtained. The said components can also be
placed into the first tank in a differant sequence. If
desired, all the said components can be introduced into
the first stirred tank and kept at reaction temperature
until the initially disperse reaction mixture has the
sought-after appearance.
The reaction according to the invention is carried out at
atmospheric pressure or the pressure which establishes
- - 9
itselE in the stirred tank, apart from the vacuum
described for the more rapid discharge of the alcohol
from the reaction mixture. As already mentioned, in each
subsequent stirred tank, a higher amount of polyhydroxy-
fatty amide is reacted than in the preceding tank. It isalso preferred to carry out the reaction in each sub-
sequent stirred tank at a temperature at most equal to
(that is no higher than) that in the preceding tank and
preferably at a somewhat lower temperature (expediently
1 to 5C). The homogeneous li~lid product, solid at room
temperature, in the last stirred tank essentially
comprises polyhydroxy-fatty amide, unreacted N-alkyl
polyhydroxyamine and the viscosity-decreasing liquid
which may have been used. Generally, the resulting
product is taken up in additional liquid (solvent) and/or
water, by which means not only is a rapid cooling
achieved, but also a product is obtained which flows
readily at room temperature and thus is easily
handleable. The polyhydroxy-fatty amide can also be
converted into the form of flakes, grains, granules or
powders.
The process according to the invention has a series of
advantages. The linear polyhydroxy-fatty amide is
obtained in virtually quantitative yield. It only con-
tains very slightly interfering by-products such as
cyclic polyhydroxy compounds. It is thus possible by the
process according to the invention to prepare
polyhydroxy-fatty amides in high yield (space-time yield)
and in high purity. The linear fatty amide (melt) is
slightly yellow colored, therefore has the desired good
color. The process according to the invention is continu-
ous and can be carried out in stirred tanks which are
simple in terms of apparatus. A further essential advant-
age results therefrom, that is that the reaction can be
carried out optimally with respect to automation, control
and maintenance of constant reaction conditions, which is
obviously of great importance for uniform product
quality. A further essential advantage is that, in the
"' - 10 -
steady state phase of the reaction, even the alcohol
formed in the reaction is frequently sufficient as
solvent and complete homogeneity is always present. This
ensures a high reaction rate and simultaneously the high
degree of conversion and the high purity of the product
The clear homogeneous reaction mixture permits relatively
low reaction temperatures from the beginning, which in
turn has a favorable effect on the purity of the
polyhydroxy-fatty amide.
The following can further be stated below on the basic
compounds to be used in the process according to the
invention and on the N alkylpolyhydroxyamine and on the
alkyl ester of the fatty acid: the basic compounds are
preferably alkali metal compounds in the form of alkali
metal alkoxides and/or alkali metal hydroxides. The
alkali metal alkoxides are preferably alkali metal Cl to
C4-alkoxides, the Cl to C3-alkoxides beinq pre~erred. The
alkali metal methylate is particularly preferred. The
alkali metal is preferably sodium or potassium. The
alkali metal hydroxides are preferably sodium hydroxide
and potassium hydroxide.
The starting compounds N-alkylpolyhydroxyamine and al~yl
esters of fatty acids are likewise known compounds and
commercially available. They are furthermore extensively
25 described in the publication WO 92/06073 mentioned at the
outset, which is incorporated herein by reference. The
N-alkylpolyhydroxyamines can contain alkyl radicals and
polyhydroxy radicals of the most varied type. As regards
the polyhydroxy portion, this preferably originates from
polyhydroxy compounds selected from the group comprising
the reducing sugars or reducing sugar derivatives.
Preferred reducing sugar compounds are the mono-
saccharides, preferably pentoses and hexoses, and the
oligosaccharides, preferably disaccharides and tri-
accharides. Examples of monosaccharides are fructose,
glucose, galactose, mannose, sorbose and talose as
-- 2~l27~i1,,~
hexoses and arabinose, ribose and xylose as pentoses. Of
the monosaccharides, the hexoses are preferred. Examples
of oligosaccharides (polysaccharides) are lactose,
maltose, maltotriose and the like. Of the oligosacchar-
ides, the disaccharides are preferred. Particularlypreferred polyhydroxy compounds are the (reducing)
hexoses, in particular glucose. ~he alkyl radical in the
N-monoalkylpolyhydroxyamine can alternatively be a
hydroxyalkyl radical, for example -C~2C~2OH. It is prefer-
ably a Cl to C4-alkyl, for example methyl, ethyl, propyl
or isopr~pyl. Preferred N-alkylpolyhydroxyamines are
therefore the N-C1 to C3-glycamines, preferably of
fructose, gluco e, galactose, mannose, sorbose or talose
or mixtures thereof. Particularly preferred N-alkylpoly-
hydroxyamines are the N-Cl to C3 glucamines, N-methyl-
glucamine being very particularly preferred.
The alkyl esters of fatty acids are preferably C1 to C4
alkyl esters of fatty acids, methyl, ethyl, propyl or
isopropyl being preferred. The methyl esters of fatty
acids are particularly preferred. The fatty acid radical
(the acyl group) generally has 6 to 24 carbon atoms,
preferably 8 to 18 carbon atoms. It can be saturated or
unsaturated (preferably monounsaturated to triunsatur-
ated). Examples which can be mentioned are the acyl
radicals of caprylic, capric, lauric, palmitic, stearic
and oleic acids, as well as coconut acyl, tallow acyl,
preferably hardened tallow acyl, and the like. The fatty
acid radical is frequently a mixture of two or more acyl
groups, for example C,2 and Cl~-acyl (Cl2/l4), Cl6 and Cl9-
acyl (C16/l8) or C12 to Cl8-acyl.
The inventlon will now be described in more detail with
reference to examples.
Examples 1 to 5
These examples were carried out in two stirred tanks
arranged in a cascade. The abbreviation "MW" used below
. ~ .
~ ~ 2'~
- - 12 -
denotes molecular weight.
Example l ~.
Product feed to the first tank~
1.00 mol of N-methylglucamine (MW = 195)
1.00 mol of the methyl ester of Cl2~,4-fatty acid tMW =
220)
0.05 mol of sodium methylate (MM = 541 in the form of a
30% strength by weight methanolic solution
Product feed to the seco~d tank: .
0.50 mol of propylene glycol (MM = 76), that is 10% by
weight (based on solid product)
.
Procedure:
In order to start the continuous preparation of N-methyl~
glucamide, 3 mol of the methyl ester Of Cl2/l4 fatty acid
are first introduced into the first stirred tank and
heated to about 95C. 3 mol of flowing, that is heated to
about 130C, N-methylglucamine and then 0.15 mol of
sodium methylate in the form of a 30% strength by weight
methanolic solution are introduced into the heated ester.
~ 20 ~he mixture is kept at about 95C and at the pressure
: which is established until a single-phase liquid (clear
homogeneous) reaction mixture is obtained. As soon as
this mixture is present in the first stirred tank, the
continuous op~ration begins, that is continuously and
simultaneously, per hour, the products specified abo~e
under "product feed to the first tank~' are ft_d to the
first tank, maintaining the temperaturst mentioned of
. about 95C. The clear homogeneous reaction mixturet
leaving the first tank and entering the second tank (the
two tanks o the cascade are filled and in the steady
state) shows a degree of conversion of 82.2 mol%, based
on N-methylglucamine. The mean residence time in the
first tank iB 1 . 9 hours. In the second stirxed tank, the
reaction mixture is held at 90C and a vacuum of 22 mbar,
the methanol being distilled off. The propylene glycol
J~
amount specified above is continuously added per hour to
the second tank to decrease the viscosity of the reaction
mixture in the second tank. The mean residence time in
the second tank, in which the amidation reaction pro-
ceeds, is 2.1 hours. The clear product leaving the secondtank exhibits a conversion rate of 94.5 mol%, based on
N-methylglucamine.
Example 2
Product $eed to the ~irst tank:
1.00 mol of N-methylglucamine
1.10 mol of methyl laurate (MW = 214)
0.05 mol of sodium methylate as in Example 1
10.00 mol of methanol (MW z 32)
Product feed to the second tank: none
Example 3
Product feed to the first tank:
1.00 mol of N-methylglucamine containing 0.07 mol of
catalyst
1.06 mol of methyl ester of Cl2/l4-fatty acid (MW = 220)
2.00 mol of methanol
Product feed to the second tank:
0.50 mol of propylene glycol (10% by w~ight) -.
:
The mixture of N-methylglucamine and 0.07 mol of catalyst
was prepared in such a manner that 1 mol of N-methyl-
glucamine and 0.07 mol of NaO~ were each mixed in theform of a 35~ strength by weight aqueous solution and the
total solution was dehydrated with the aid of a thin-film
evaporator at up to 130C and a vacuum of 50 mbar down to
0.3% by weight residual water. The mixture is fed to the
first tank as a melt (about 130C).
~ L~L 3 r
Example 4
Product feed to the first tank-
1.00 mol of N-methylglucamine
1.10 mol of methyl stearate (~ - 298)
0.03 mol of sodium methylate as in Example 1
Product feed to the second tank:
1.1 mol of propylene glycol (20% by weight)
Example 5
.. ..
Product feed to the first tank:
1.00 mol of ~-methylfructamine
1030 mol of methyl ester of Cl2/~4-fatty acid (MW = 220
0.15 mol of sodium methylate as in Example 1
20.00 mol of methanol
'
Product feed to the second tank:
0.50 mol of propylene glycol (10% by weight)
Examples 2 to 5 were carried out similarly to Example 1.
Examples 6 to 8
These examples were carried ou~ in three stirred tanks
arranged in a cascade. ~he abbreviation MM used below
also denotes molecular weight here.
Example 6
! ' I '
Product feed to the first tank:
1.00 mol of N-methylglucamine
1.06 mol of methyl ester of C,2/,4-fatty acid (MW - 220)
0.07 mol of sodium methyla~e in the form of a 30%
strength by weight methanolic solution
2.00 mol of methanol
: .
~2~
- - 15 -
Product feed to the second tank:
0.50 mol of propylene glycol t10% by weight)
Procedure-
In order to start the continuous preparation of N methyl-
glucamide, the procedure is followed as in Example 1, atemperature of 87C being established and maintained. As
soon as the described reaction mixture is present in the
first stirred tank, the continuous operation begins, that
is the products specified above under "produc~ feed to
the first tank~ are continuously and simultaneously fed
to the first tank per hour, maintaining the temperature
mentioned of about 87C. The clear homogeneous reaction
mixture leaving the first tank and entering into the
second tank (the three tanks of the cascade are filled
and in the steady state) shows a conversion rate of
77~4 mol%, based on N-methylglucamine. The mean residence
time in the first tank is 1.6 hours. In the second
stirred tank, the reaction mixture is kept at 80C and a
vacuum of 165 mbar, the methanol being distilled off down
to a residual content of 0.95g by weight, based on solid
product. The propylene glycol amount specified above is
continuously added per hour to the second tank to
decrease the viscosity of the reaction mixture in the
second tank. The mean residence time in the second tank,
in which the amidation reaction proceeds, is 1.9 hours.
The single-phase liquid reaction mixture leaving the
second tank and entering into the third tank shows a
conversion rate of 93.0 mol~, based on N-m~thylglucamine.
In the third stirred tank, the reaction mixture is kept
at 80C and a vacuum of 26 mbar, methanol being further
distilled off. The mean residence time in the third
stirred tank, in which the amidation reaction pxoceeds
further, is 2 hours. The clear product leaving the third
tank shows a conversion rate o ~8 mol%, based on N-
methylglucamine.
- 16 -
Example 7
Product feed to the first tank-
1.00 mol of N-methylglucamine
1.00 mol of methyl stearate (MW = 298)
0.03 mol of sodium methylate as in Example 6
Product feed to the second tank.
1.2 mol of propylene glycol (20% by weight)
Example 8
Product feed to the first tank:
1.O mol of N-methylglucamine containing 0.15 mol of -
catalyst
1.3 mol of methyl ester of Cl2~14-fatty acid (MM = 220)
20.0 mol of methanol
Pxoduct feed to the second tank:
0,5 mol of propylene glycol (10% by weight)
. . .
The mixture of N-methylglucamine and 0~15 mol of catalyst
was prepared in such a manner that 1 mol of N-methylgluc-
amine and 0.15 mol of NaO~ were each mixed in solid form
and the mixture was fused. It is fed in this form to the
first tank.
.
~xamples 7 and 8 were carried out similarly to Example 6,
in Example 7, in the second stixred tank, the methanol
being distilled off down to a residual content of 1.4% by
weight, based on solid product, and in Example 8, down to
20~ by weight, based on solid product (that is, the solid
content in the reaction mixture).
Results of Examples 1 to 8:
The degree of conversion achieved of the N-alkylpoly-
hydroxyamine used is very high in all examples. The
linear polyhydroxy-fatty amide obtained is very pure. The
- ~12~
- 17 -
content of cyclic compounds is .in the range from less
than 200 ppm to at most 1000 ppm (the determination was
carried out by quantitative thin-layer chromatoqraphy).
The polyhydroxy-fatty amide also contains only a very
1 5 little residllal methanol, since the alcohol is removed aa
completely as possible by distillation in the second tank
(in the case of two stirred tanks) or in the third tank
(in the case of three stirred tanks3O
In the table below, the degree of conversion in percent,
based on ~-alkylpolyhydroxyamine used, which was obtained
in Examples 1 to 8, is summarized. The table also
contains the procedural characteristics of Examples 2 to
5 and 7 and 8 and, for the sake of completeness, also
those of the ~xamples 1 and 6 described in detail~ The
following abbreviations are used in the table:
"RT" for residence time in hours
"DC" for the said degree of conversion.
Table
. . .
fir~lt t~nk second tanX I third tllnk I
l l l l l I l l l I
I Elcu~pl~ I nc I RT I DC I C I R~ I mbur I DC I C I R~ I Jnbsr I DC
+ ~- I i I I I ~ . .1 1 1 1
20 1 1 1 95 1 1.9 1 82.2 I go 1 2.1 1 22 1 94.5 1 -- I -- l -- l --
+ + ~ +
2 167 1 1.1 ! 65.4 1 97 1 1.9 1 46 1 86.6 1 -- I -- l -- l -- I
+ + ~ + + + + ~ ~ i
3 187 1 1.6 1 77.4 1 80 1 2.0 1 23 1 93.9 1 -- I -- l -- l --
4 1 120 1 0.25 1 70.4 1 loo 1 0.25 1 98 1 85.1 1 -- I -- l -- l --
+------ --+--~ __ _+_____~_____+_____~_____+_____~_____ i :
1 5 1 60 1 1.3 1 65.3 1 60 1 3.2 1 105 1 88.1 1 -- I -- I -- I -- I
2 5 1 6 1 87 1 1.6 1 77.4 1 80 1 1.9 1 165 1 93.0 1 80 1 2.0 1 26 1 98.0 1
~______f____~____~_____~_____~_____~_____~_____~_____+_____~___--+------i : .
7 1 120 1 0.25 1 70.4 1 loo 1 0.25 1 436 1 85.0 1 loo 1 0.25 1 29 1 93.3 1
~______+____~____~_____ +_--------~---- --~----------+----------+----------t-----~ ----------+----------'1
1 8 1 60 1 1.3 1 6s.3 1 60 1 2.6 1 600 1 8s.~ 1 60 1 3.3 1 94 1 97.5 1'. '. I ' ~ L ~ I I I ! ' ' .
