United States Patent (19) (11) 4,267,161

Ziegenhain 45 May 12, 1981

54 METHOD OF MAKING ALUMNUM
CHLOROHYDRATE FOREIGN PATENT DOCUMENTS
(75) Inventor: William C. Ziegenhain, Ponca City, 1947177 4/1971 Fed. Rep. of Germany ... 260/448 AC
Okla. 1414854. 11/1975 United Kingdom ................... 264/63
(73) Assignee: Conoco, Inc., Ponca City, Okla. Primary Examiner-Brian E. Hearn
Attorney, Agent, or Firm-Cortlan R. Schupbach, Jr.
(21) Appl. No.: 142,587
22 Filed: Apr. 21, 1980 57 ABSTRACT
(51 Int. Cl............................. C01F 7/56; CO1F 7/02 Aluminum chlorohydrate is prepared by a method com
prising -
(52) U.S. C. .................................... 423/462; 423/472;
(a) forming aluminum methoxide from aluminum
423/625; 423/630; 264/63; 264/65; 264/DIG. alkoxides using methanol;
19
(58) Field of Search ....................... 423/462, 472, 630; (b) recovering aluminum methoxide as a solid precipi
260/448 AC; 264/176 F, DIG. 19, 63 tate phase, washing to remove higher alcohols and
drying to recover a powder;
56 References Cited (c) reacting the recovered powdered aluminum meth
U.S. PATENT DOCUMENTS oxide with dilute hydrochloric acid to form alumi
2,975,201 3/1961 Dickey ............................. 260/448 R num chlorohydrate.
3,865,917 2/1975 Galasso .... a 264/63
3,887,691 6/1975 Kobetz ................................. 423/462 8 Claims, No Drawings
 1.
4,267,161
2
a time sufficient to form solid aluminum methoxide in a
METHOD OF MAKING ALUMNUM liquid phase,
CHELOROHYDRATE (b) washing the obtained aluminum methoxide to
This invention relates to a method for producing remove higher alcohols and recovering solid aluminum
methoxide from the liquid phase, and
alumina fibers. More specifically, this invention relates (c) reacting aluminum methoxide with hydrochloric
to a method for producing alumina fibers by a unique acid for a time and at a temperature sufficient to form
method of forming aluminum chlorohydrate then draw aluminum chlorohydrate.
ing the aluminum chlorohydrate into alumina fibers. In accordance with the present invention, it has been
The making of inorganic ceramic fibers comprising 10
found that only methanol is effective in forming a solid
metal oxides is well known in the art. U.S. Pat. No. precipitate material which can be recovered by simple
3,865,917 shows a method of making alumina monofili filtration and which is suitable for use in alumina fiber.
ments by extruding a 50 to 60 weight percent aqueous Although some methanol is present in these fibers, it is
solution of aluminum chlorohydrate. U.S. Pat. No. easily removed because of its low volatility. The pres
3,887,691 shows methods for making hydroxy chlo 15 ence of higher molecular weight alkanols and fibers
roaluminum compounds. British Pat. No. 1,414,854 produced by other processes makes such alcohols diffi
shows a method for preparing alumina yarns by using cult to remove
hydroxy chloro aluminum compounds. U.S. Pat. No. This is not trueand degrades the properties of the fibers.
in the method of the instant invention.
3,950,478 discloses a method for spinning alumina fibers
which contain an organic polymer. British Pat. No. 20 The instant invention does not require aluminum metal
1,470,292 teaches the production of inorganic fibers The feedstock,
as a although aluminum metal can be used.
aluminum chlorohydrate produced will have the
using polyethylene oxide and alumina combinations. formula Al2(OH)Cl, where X is any number from 1-5
However, these methods deal with aluminum chlo and y is 6-X.
rohydrate or organic-containing aluminum compounds 25 Normally step (c) is carried out at reflux temperature
which are then spun into fibers. Previous methods for of the solution for a time sufficient to react substantially
obtaining aluminum chlorohydrate have been ineffi all washed aluminum methoxide to form water soluble
cient and produce aluminum chlorohydrate which con aluminum chlorohydrate. The hydrochloric acid (HCl)
tains contaminants. U.S. Pat. No. 4,024,231 shows the used in step (c) is a dilute aqueous solution usually con
water hydrolysis of aluminum methoxide in anhydrous 30 taining from about 2 to about 30 weight percent HCl.
methanol. The reference is directed toward a process Use in this range is not critical, but higher concentra
for preparing alumina and produces an aluminum meth tions of HCl decrease the effectiveness of the present
oxide which did not react with alcohol. U.S. Pat. No. invention.
2,975,201 describes the preparation of aluminum meth The aluminum alkoxides of step (a) can be any alumi
oxide by the transalcoholysis of a Ziegler organoalumi 35 num
num chemistry growth product with methanol. How aboutalkoxide from any source which contains from
2 to about 30 carbon atoms. However, in most
ever, this growth product was not treated with acid to commercial applications the aluminum alkoxides ob
form aluminum chlorohydrate solutions suitable to form tained will contain from about 6 to about 18 carbon
fibers as described in the instant invention. Aluminum
chlorohydrate is thus usually made by reacting alumi 40 atoms, with the majority of the alkoxide in the range of
from about 10 to about 18 carbon atoms.
num metal with aqueous hydrochloric acid. In carrying out the method of the present invention,
U.S. Pat. No. 3,887,691 describes the preparation of normally the recovered solid aluminum methoxide of
oxychlorides from alkoxides having a carbon atom con step (b) is washed with methanol to remove any higher
tent of from 6 to 30 carbon atoms. The patent describes alcohols present by displacement then dried to remove
aluminum alkoxides preferably having alkoxy groups 45 methanol prior to reaction with HCl. The recovery of
whose corresponding alcohols are substantially insolu the
ble in water. This reference uses an aqueous acid and nientsolid of step (b) can be made by any method conve
such as filtration or centrifugation.
produces higher alcohols. However these higher alco The reaction of the aluminum alkoxides with metha
hols tend to remain trapped in the product and alter the nol is normally carried out at a temperature of from
properties of the aluminum chlorohydrate solution. The 50
reference likewise develops two immiscible liquid pha about 130 F. to about 450 F. Preferred temperature
ses which require much separation and careful handling about 325from
range is about 150' F. to about 350 F. but from
F. to about 375 F. is most preferred.
prior to obtaining the product. In addition, the reaction of aluminum alkoxides of
It would therefore be of great benefit to provide a step (a) can optionally be carried out in a liquid phase
method wherein aluminum chlorohydrate could be 55 under pressure, although this is not critical to the pres
produced in an easily recoverable form using a simple ent invention. The reaction under pressure is simply
process containing few by-products. faster and is therefore a preferred method of carrying
It is therefore an object of the present invention to out the present invention.
provide an improved method for obtaining aluminum Once the aluminum chlorohydrate has been recov
chlorohydrate. It is a further object to provide a 60 ered as an aqueous solution with methanol, the alumi
method for obtaining alumina fibers. Other objects will num chlorohydrate is concentrated by removing metha
become apparent to those skilled in this art as the de nol and sufficient water to form a solution of sufficient
scription proceeds. viscosity suitable for drawing fibers. Fibers are then
It has now been discovered according to the present drawn from the concentrated solution. Methods for
invention that aluminum chlorohydrate can be obtained 65 drawing fibers suitable for use in the process of the
by a method comprising present invention are those well known to those skilled
(a) reacting aluminum alkoxides with methanol at a in the art and are exemplified by the procedures set
temperature of from about 130 F. to about 450 F. for forth in U.S. Pat. No. 3,865,917; U.S. Pat. No. 3,887,691;
 4,267,161
3 4
British Pat. No. 1,414,854; and French Pat. No. Once the rewash was complete, drying of the filter
2,176,041. cake was carried out by charging 1095 grams of wet
In particular, a suitable process for producing alu filtercake to a vacuum flask in a hot water bath. The
mina fibers can be found in U.S. Pat. No. 3,950,478, pressure in the flask was slowly lowered until methanol
hereby incorporated by reference in its entirety into the was distilled overhead at 14.3 inches mercury pressure.
instant specification. As set forth in this reference, or The cold water condenser was used to recover the
ganic polymers can be added to the viscous aluminum methanol condensate. Over a 4 hour period the vacuum
chlorohydrate mixture to aid in drawing fibers and was slowly increased to 26.5 inches of mercury at 85 to
enhance fiber formation. These organic polymers are 90° C. to complete drying of the aluminum methoxide.
preferably water soluble organic polymers; conve 10 The process yielded 512 grams of dried powder con
niently a non-ionic water soluble organic polymer, taining 68.3 weight percent aluminum methoxide, with
polyhydroxylated organic polymers or natural water the remainder mostly methanol which had not been
soluble gums. These polymers are preferably thermally removed during the drying procedure.
stable under the conditions of drawing the fiber. Exam The aluminum methoxide was converted to alumi
ples of preferred organic polymers include polyvinyl 15 num chlorohydrate by mixing 60 grams of concentrated
alcohol, polyacralamid, partially hydrolyzed polyacryl acid (37% HCL) into 200 grams deionized water which
amide, polyacrilic acids, polyethylene oxides, carboxy was charged to a 2 liter, 3 neck distillation flask, and
alkyl celluloses, hydroxyalkyl celluloses, alkyl cellu fitted with mixer and water cool condenser. The flask
loses, hydrolyzed starches, dextrans, quargum, polyvi and its contents were heated to 80 C. and 200grams of
nylpyrrolidones, polyethylene glycol, alginic acids, 20 dried aluminum methoxide powder containing 68.3
polyisobutylene derivatives, copolymers of polycylox weight percent aluminum methoxide was added slowly
anes such as with ethylene oxide, polyurethanes and over a 10 minute period. The contents of the flask were
esters and ester copolymers. allowed to digest at the boiling point for 18 hours. It
The most preferred organic polymers useful in draw was noted that the boiling point temperature declined as
ing fibers are straight chain polyhydroxylated organic 25 methanol was released from the reaction. The reaction
polymers such as polyvinyl alcohol, polyvinylpyrroli occurred mainly at about 150 F. The reactor contents
done or polyethylene oxide. were cooled and 402 grams of viscous liquid were re
The viscosity of the drawing composition is prefera covered which were then filtered through No. 2 What
bly less than 300 poise most preferably from 0.1 to 100 man filter paper to remove inert solids. The filtrate was
poise, especially when very small diameter fibers are to 30 then heated under 26 inches of mercury vacuum at 85
be drawn. C. in water solution for a period of time sufficient to
The use of elevated temperatures increases the reac concentrate the product at 230.4 grams the final prod
tion rate, together with selectivity to Al(OCH3)3. At uct. The density of the final concentrate was 1.252
room temperature the methanol and alkoxide form a grams per cubic centimeter with an aluminum content
gel-like reaction product. Phase separation is not possi 35 of 10.38 weight percent and a chlorine content of 8.68
ble with this product unless large excesses of methanol weight percent. Calculated mole ratio of aluminum to
are used. chlorine was 1.45/1.0.
The invention is more concretely described with EXAMPLE 2
reference to the examples below wherein all parts and
percentage are by weight unless otherwise specified. 40 Concentrated aqueous solutions of the reaction prod
The examples are provided to illustrate the instant in uct resulting from example 1 (aluminum chlorohydrox
vention and not to limit it. ide) were tested for fiber formation by attempting to
EXAMPLE
pull fibers in the laboratory using a glass rod. The glass
rod was simply touched to the solution and withdrawn
A 10 gallon Pfaulder mixer (trademark of and sold by 45 slowly. Fibers could be drawn without additives, but
Pfaudler Co., Division of Sybron Corp, Rochester, fiber formation was enhanced by the addition of 1-2
N.Y.) was charged with 9486 grams of reagent grade percent of a high molecular weight polyvinyl alcohol.
methanol to which was added 1770 grams of aluminum Thus it is apparent that the instant invention provides
alkoxides obtained from a commercial Ziegler growth an improved process for the production of aluminum
process. The contents of the reactor were heated to 200 50 chlorohydrates suitable for forming alumina fibers. The
F. and maintained at this temperature for 2 hours. The process utilizes the formation of aluminum methoxides
internal pressure ranged from 30 to 32 pounds per which separates from the liquid as a solid and is easily
square inch gauge (psig). The reactor was then cooled recoverable. The recovered solid is easily converted to
to 160 F. and filtering was begun. An aluminum meth aluminum chlorohydrate suitable for forming fibers.
oxide solid weighing about 1160 grams was recovered 55 Problems of undesirable by-products in critical separa
leaving about 400 grams of solids in the Pfaulder as a tion by the prior art processes are avoided.
holdup. The total crude alcohol filtrate recovered was While certain embodiments and details have been
9667 grams. shown for the purpose of illustrating this invention, it
The filtercake solids from the aluminum methoxide will be apparent to those skilled in this art that various
produced weighed 1151 grams and were recharged to 60 changes and modifications may be made herein without
the Pfaulder after the mixer was cleaned. Fresh analyti departing from the spirit or scope of the invention.
cal reagent grade methanol (94.55 grams) was added to I claim:
the mixer. The materials were mixed and reheated to 1. A method for preparing aluminum chlorohydrate
198 F. for 30 minutes with the pressure holding at comprising
about 30 psig. The reactor contents were then cooled to 65 (a) reacting aluminum alkoxides with methanol at a
183 F. and filtration was begun. Filtration used What temperature of from about 130 F. to about 450° C.
man No. 5 filter paper and collected 9530 grams of for a time sufficient to form solid aluminum meth
filtrate and 1095 grams of solid. oxide in a liquid phase,
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4,267,161
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(b) washing the aluminum methoxide recovered with 4. A method as described in claim 3 wherein the
methanol to remove higher alcohols, then recover aluminum alkoxide contains from 2 to 30 carbon atoms.
ing solid aluminum methoxides from the liquid 5. A method as described in claim 4 wherein the
phase, and aluminum alkoxide contains from about 6 to 18 carbon
(c) reacting aluminum methoxide with aqueous hy atOnS.
drochloric acid for a time and at a temperature 6. A method as described in claim 5 wherein the
sufficient to form aluminum chlorohydrate. recovered solid of step (b) is washed with methanol to
2. A method as described in claim 1 wherein step (c) remove higher alcohols then dried prior to reaction
is carried out at reflux temperature for a time sufficient with hydrochloric acid.
10 7. A method as described in claim 6 wherein the
to react substantially all wash aluminum methoxide to recovery of solids from step (b) is carried out by filtra
form water soluble aluminum chlorohydrate. tion or centrifugation.
3. A method as described in claim 2 wherein the 8. A method as described in claim 7 wherein the
hydrochloric acid is in a dilute aqueous solution con reaction of step (a) is carried out at a temperature of
taining from about 2 to about 30 weight percent hydro 15 from about 325 F. to about 375 F.
chloric acid. k is k is k

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