U.S. patent application number 10/935595 was filed with the patent office on 2005-02-10 for granular alkali metal alkoxides and alkaline earth metal alkoxides.
This patent application is currently assigned to Degussa AG. Invention is credited to Harthun, Andreas, Metz, Josef, Noppe, Andre, Theis, Christoph.
Application Number | 20050033096 10/935595 |
Document ID | / |
Family ID | 7702250 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050033096 |
Kind Code |
A1 |
Harthun, Andreas ; et
al. |
February 10, 2005 |
Granular alkali metal alkoxides and alkaline earth metal
alkoxides
Abstract
An alkali metal alkoxide or alkaline earth metal alkoxide in
granular form.
Inventors: |
Harthun, Andreas; (Moembris,
DE) ; Theis, Christoph; (Niederkassel, DE) ;
Noppe, Andre; (Sankt Augustin, DE) ; Metz, Josef;
(Marl, DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Degussa AG
Duesseldorf
DE
|
Family ID: |
7702250 |
Appl. No.: |
10/935595 |
Filed: |
September 8, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10935595 |
Sep 8, 2004 |
|
|
|
10270114 |
Oct 15, 2002 |
|
|
|
Current U.S.
Class: |
568/700 |
Current CPC
Class: |
C07C 31/30 20130101;
C07C 69/716 20130101; C07C 67/343 20130101; C07C 67/343
20130101 |
Class at
Publication: |
568/700 |
International
Class: |
C07C 029/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 15, 2001 |
DE |
101 50 328 |
Claims
1-12. (Canceled).
13. A granular alkaline earth metal alkoxide wherein the alkoxide
radical is that of an alcohol selected from the group consisting of
methanol, n-propanol, isopropanol, allyl alcohol, n-butanol,
isobutanol, tert-butanol, amyl alcohol (pentanol), the isomers of
pentanol, hexanol and the isomers of hexanol.
14. The granular alkoxide as claimed in claim 13, wherein the
cationic component of the alkoxide is magnesium ions, calcium ions
or mixtures thereof.
15. The granular alkoxide as claimed in claim 13, wherein the
cationic component of the alkoxide is magnesium ions.
16. The granular alkoxide as claimed in claim 13, wherein the
granules of alkoxide have a diameter ranging from 100 .mu.m to 10
mm.
17. The granular alkoxide as claimed in claim 13, which has an
alkoxide content of 50-100% by weight.
18. The granular alkoxide as claimed in claim 16, which has an
alkoxide content of >98% by weight.
19. A granular calcium alkoxide.
20. A granular calcium metal alkoxide wherein the alkoxide radical
is that of an alcohol selected from the group consisting of
methanol, ethanol, n-propanol, isopropanol, allyl alcohol,
n-butanol, isobutanol, tert-butanol, amyl alcohol (pentanol), the
isomers of pentanol, hexanol and the isomers of hexanol.
21. The granular alkoxide as claimed in claim 19, wherein the
granules of the alkoxide have a diameter ranging from 100 .mu.m to
10 .mu.m.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to alkali metal and alkaline
earth metal alkoxides in granular form.
[0003] 2. Description of the Background
[0004] Alkoxides are used for a wide variety of applications.
Alkoxides are used in aldol addition reactions,
esterification/transesterification reactions, malonic ester
syntheses, ether formations, as well as being generally used as a
base in other reactions. In addition, alkoxides are widely used in
the food industry, for example in margarine production or vitamin A
synthesis, in the pharmaceutical industry, for example in the
preparation of antibiotics, analgesics, chemotherapy drugs and
anti-epileptics, in the agrochemicals industry, for example in the
production of herbicides and fungicides, and in many other fields,
for example in the production of optical brighteners, UV absorbers
and photoinitiators.
[0005] For these purposes, the alkoxides are generally used in the
form of their alcoholic solutions or, if the alcohol is undesirable
and it is technically and logistically possible, in powder form if
available.
[0006] A disadvantage in the handling of an alkoxide powder is its
tendency to form fine dust during packaging and transfer
operations, because this dust is hazardous to human beings and
machinery because of the strongly corrosive action of the alkoxides
and because of the ease with which they spontaneously ignite in the
atmosphere.
[0007] When alkoxides are used as reactants, exothermic reactions
which frequently occur and are difficult to control also represent
an additional, not inconsiderable process risk. These hazard
potentials require a very high outlay in terms of process
engineering and apparatus.
SUMMARY OF THE INVENTION
[0008] Accordingly, one object of the invention is to provide
alkali metal and alkaline earth metal alkoxides in a form which
does not have the indicated disadvantages, in particular the
formation of corrosive fine dust during handling.
[0009] Briefly, this object and other objects of the present
invention as hereinafter will become more readily apparent can be
attained by the preparation of an alkoxide in granular form.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] It has been found that alkali metal alkoxides and alkaline
earth metal alkoxides of alcohols having from 1 to 12, preferably
from 1 to 6, carbon atoms, can be converted by means of particular
process engineering measures into a solid granular form by means of
which the risks on handling the abovementioned alkoxides and their
use in customary reactions can be considerably reduced and
minimized. The invention therefore provides alkali metal alkoxides
and alkaline earth metal alkoxides of alcohols having from 1 to 12,
preferably from 1 to 6, carbon atoms in granular form preferably
produced by the fluidized-bed spray granulation process. As a
coarsely particulate material, the alkoxides in granular form are
easy to store, convey, meter and mix, since they do not dust, do
not agglomerate and do not tend to bridge in this form of
solid.
[0011] Alkali metal cations components which can be present in the
alkoxide include lithium, sodium and/or potassium ions. Preferred
alkali metal alkoxides are, in particular, sodium and potassium
alkoxides.
[0012] Alkaline earth metal cations which can be present in the
alkoxide include magnesium and/or calcium ions. Preferred alkaline
earth metal alkoxides are, in particular, magnesium alkoxides.
[0013] The alcohol radical in the alkoxide is derived from an
aliphatic, unbranched or branched, saturated or unsaturated alcohol
having from 1 to 12, preferably from 1 to 6, very particularly
preferably from 1 to 4, carbon atoms.
[0014] Preferred radials are the radicals derived from methanol,
ethanol, npropanol, isopropanol, allyl alcohol, n-butanol,
isobutanol, tert-butanol, amyl alcohol (pentanol) including the
various isomers of pentanol and hexanol including the various
isomers of hexanol. However, the invention relates in particular to
granular alkoxides of methanol, of ethanol, of propanol and of
butanol in their various isomeric forms. This listing is, however,
merely by way of example and does not restrict the scope of the
invention.
[0015] The alkoxide content of the granular material is 50-100% by
weight, preferably 90-99% by weight and in particular >98% by
weight. As a process engineering measure for producing the granular
materials, fluidized-bed spray granulation can be employed. The
shape and diameter of the granules can be set and varied by means
of the production and drying conditions. The granules are
preferably present in an asymmetric, approximately spherical
form.
[0016] The diameter of the granules extends from microns to the
centimeter range. Preference is given to producing granules having
a diameter ranging from 100 .mu.m to 10 mm. Since the granule size
depends essentially on the granulation conditions, the quoted
granule size does not constitute a confining limitation of the
invention.
[0017] As a result of the granular form, the flowability index
(ffc) is greatly increased compared to a pulverulent alkoxide,
which leads to considerable advantages in handling.
[0018] Furthermore, the speed of dissolution is determined, inter
alia, by the granule size and this makes the desired reaction more
uniform. As a result, exothermic chemical reactions can be
controlled significantly more readily.
[0019] Although the spontaneous ignition temperature (without time
limit) is not reduced, a dust explosion can be ruled out for the
granular material because virtually no dust occurs in transfer and
packaging operations.
[0020] The most widely used of the solid alkali metal alkoxides is
sodium methoxide. For this reason, the materials properties of
sodium methoxide powder and granular sodium methoxide are compared
below by way of example. However, the property differences are
generally present for the granular alkoxides as specified in the
above description and therefore the scope of the invention should
not be understood to apply exclusively to sodium methoxide.
1 Sodium methoxide Granular sodium powder methoxide Bulk density
[g/l] ca. 500 ca. 400 Tamped density [g/l] ca. 645 ca. 410
Densification [%] 22.5 2.5 Flowability index (ffc) 5.19 18.74
Specific surface area 6.4 17 [m2/g] (DIN 66131) Spontaneous
ignition 55-60 50-55 temperature in the presence of air [.degree.
C.]
[0021] It can be observed from the data in the table that the
granular sodium methoxide is a solid which has significantly more
advantageous properties in terms of handling when compared to
sodium methoxide powder. The indicated, lower bulk density of the
granular material is essentially dependent on the granule diameter
which can in turn be altered by variation of the granulation
conditions. The granular material examined has an average diameter
of 2 mm. However, these data are purely by way of example and
should not be interpreted as a limitation of the scope of the
invention pertaining to granule diameter or the industrially
achievable bulk density of the granular alkoxides.
[0022] The granular material has considerably better flow
properties than powder and in a tamping test undergoes a compaction
of only 2.5%. In contrast, the powder is densified by 22.5%.
[0023] According to the invention, the granular alkoxide provides a
form of solid alkoxide which has considerably better storage,
conveying and metering properties than the corresponding
powder.
[0024] The dissolution rate of the solid sodium methoxide in
different alcohols is summarized below. For this purpose, 25 g of
solid are stirred under inert gas conditions in 100 g of ethanol,
and 40 g of solid are stirred in 100 g of methanol.
2 Methanol Ethanol Sodium methoxide 6 10 powder [min] Granular
sodium 16 12 methoxide [min]
[0025] A comparison of the dissolution rates of sodium methoxide
powder and granules clearly shows that the granular material
dissolves more slowly at the same stirring rate than does the
corresponding powder. However, this materials property of the
granular material has novel advantages in batchwise exothermic
reactions. A reduced dissolution rate of the alkoxide allows the
reaction with the alkoxide to proceed more uniformly. This effect
is observed even in polar, protic solvents in which alkoxides
dissolve to only a slight extent.
[0026] An example is the carbonylation of propionic esters in
dimethylformamide. Owing to the extremely high CO uptake and
evolution of heat which occur, this reaction is a particularly
suitable model reaction.
[0027] Having generally described this invention, a further
understanding can be obtained by reference to certain specific
examples which are provided herein for purposes of illustration
only and are not intended to be limiting unless otherwise
specified.
EXAMPLES
Comparative Example
[0028] Carbonylation of Ethyl Propionate Using Sodium Methoxide
Powder
[0029] The carbonylation of ethyl propionate using sodium methoxide
powder in dimethylformamide displays a temperature maximum of
80.degree. C., while at the same time a pressure drop of about 10
bar occurs in the autoclave and the volume flow of CO is
simultaneously increased by 500%.
Example of the Invention
[0030] Carbonylation of Ethyl Propionate Using Granular Sodium
Methoxide:
[0031] The carbonylation of ethyl propionate using granular sodium
methoxide proceeds considerably more moderately. The maximum
temperature is only 70.degree. C. with an insignificant drop in
pressure and a maximum volume flow of CO of 20% of the maximum
volume flow of CO in the comparative example.
[0032] The uniform way in which the reaction proceeds surprisingly
has no influence on the space-time yield.
[0033] The example of the carbonylation of ethyl propionate using
granular sodium methoxide makes it clear that the granular alkoxide
not only has advantages in mechanical handling but also displays
considerable advantages in conducting exothermic reactions.
[0034] The disclosure of German priority application Serial No. 101
50 328.8 filed Oct. 15, 2001 is hereby incorporated by reference
into the present application.
[0035] Obviously, numerous modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *