Download WM Att/a

Jan. 23, 1962
H. s. HALBEDEL ETAL
3,018,162
ANHYDROUS METAL FLUOBORATES
Filed April 15. 1960
——————-—>
METAL
PLUORIDE
_
*—’—*
BF, POLAR SOLVENT
soLu'noN
REACT SEVERAL DAV-9 WITH
146/ TA 7'/0/V AND DEC/7N7’
RE SIDUE
METAL FLUORIDE
.
so LUTION
PRODUCT A
METAL an,
1
soumou 1N
pomp. sowam
BFa
BFg TREATME/VTW/Tf/
COOLING; F/LTER
mpuma METAL
FILTRATE
f
3P4 CRYSTALS
T
WASH W/TH
ETHER AND
3P3
SOLVENT
PUMP DRV
PRODUCT B
METAL BF4
CRYSTALS
HAROLD S. HALBEDEL & WALTER B.FIELD, INVENTORS.
BY
WM Att/a
United States Patent O?ice
E?ldddd
Patented Jan. 23, 1962
1
2
3,018,162
down, agitating the resultant solution, treating the solution
with additional boron tri?uoride, preferably diluted with
ANHYDRGUS METAL FLUOBQRATES
small amounts of inert gas and recovering resultant anhy
drous metal ?uoborate crystals. The anhydrous metal
?uoborate crystals are found to be crystals of the solvated
pany, Cleveland, Chic, a corporation oft‘ Uhio
type, that is, their crystalline structure has a polar solvent
Filed Apr. i5, 196%), Ser. No. 22,447
rather than water coupled therein.
6 Claims. (Ci. 23-59)
If a solution of anhydrous meal ?uoborate is desired,
This invention relates to anhydrous metal ?uoborates
the above procedure may be modi?ed by elimination of
and to the methods of their preparation.
the BF3 crystallization addition step. The resultant metal
Metal ?uoborates have found application as curing 10 ?uoborate solution may be packaged for use as a resin
catalysts for various resins, such as, for instance, epoxy
curing catalyst.
resins, and for electroplating bath addition agents. The
A better understanding of the general type of applicants’
curing of epoxy resins, however, frequently takes place in
procedure may be obtained from the accompanying ?ow
Harold S. Halhedel, Euclid, and Walter B. Field, Cleve
iand, @hio, assignors to The Harshaw Chemical Com
a volatile organic solvent wherein the presence of water
sheet. The ?ow sheet shows the addition of a metal ?uo
and particularly the presence of water in the curing cata 15 ride to a B133 polar solvent solution. The concentration
lyst is undesirable. Fluoborates of lead, tin, cadmium,
of BFB may be in the range of from 5% to 50%; the preiron, indium, nickel and silver are valuable salts in plat
ferred range being from 15 % to 40%. The resultant mix
ing baths and are commonly sold in solution form as 50%
ture is then reacted for tWo or more days with agitation
concentration. The shipping and packaging of such solu
tions, however, is a major problem which could be elimi
nated by the preparation of ?uoborates in anhydrous form.
and then decanted. The residue which is primarily metal
?uoride or metal ?uorideaBFa complex may be recycled
to the B133 polar solvent solution. The resultant solution,
Most ?uoborates as commonly prepared contain a cer
which is designated on the ?ow sheet as Product A, may
tain amount of water of hydration. The better known
be drawn ed and packaged for use as a resin curing agent.‘
‘methods of preparation are: (a) the reaction of boron 25 This product is particularly useful where a slight excess
tri?ucride with heated ?uorides of certain metals; and
of BFS is not undesirable in the end use. As an alter
(b) the reaction of ?uoboric acid with a halide, oxide,
nate to the packaging of the product at this point, the
hydroxide, carbonate, nitrate or sulfate of a metal. In
solution which consists of a metal ?uoborate in a BF3
general, ?uoborates of group III-B meta-ls and the alkali
polar solvent solution may be drawn oil’ and the BFa con
metals, with the exception of lithium, are readily dehy
centration slowly increased with cooling to about 15% to
drated by warming ‘or the use of desiccants. Other ?uo~
40% of B133 in polar solvent, the amount of 8P3 added
borates and more speci?cally the ?uoborates of lithium,
groups lI-B, II~B, III, IV-B, transition metals and alkaline
being that which will produce maximum precipitation.
the strongly coupled Water of hydration which is found
solution. Crystals recovered from the ?ltration operation
The solution, thus treated, is then ?ltered. The ?ltrate
earth metals are strongly coupled to their waters of hy
from this operation with the addition of BFg and polar
dration. Various attempts have been made to remove 35 solvent may be recycled to the initial BF3 polar solvent
in certain metal ?uoborate crystals. When a simple ap
are impure metal ?uoborate crystals which are washed
plication of heat is employed, it is found that these metal
with ether and pump dried to obtain puri?ed metal ?uo
?uoborate crystals lose water at about 40° C. to 60° C.
borate crystals, designated as Product B on the flow sheet.
However, the metal fluoborate is also subjected to a de 40
The reaction which takes place may be written as fol
composition process wherein there is a reversion to boron
lows:
?uoride and metal ?uoride. Attempts have also been
made to remove the water of hydration by an azeotropic
where M is a metal selected from the group consisting of
distillation process. The azeotropic distillation process
employed benzene as the immiscible liquid. The proce 45 lithium, li-B, 11-13, Ill, IV-B, alkaline earth metals and
transition metals, R is an oxygen containing polar sol
dure did remove the bulk of water, but complete dehy
vent preferably selected from the group consisting of
dration could not be effected. Continued distillation
methanol and ethanol, and n is an integer equal to the
merely resulted in decomposition of the meal ?uoborate.
valence of the metal M.
Metal ?uoborates which contain the ET, radical and
The method of preparation of this invention is depend
liberate the BF; ion in solution should not be confused 50
out
upon the discovery that ?uobcrates result from the
with metal ?uoride-B193 complexes. Anhydrous metal
dissolution of metallic ?uorides in coordination complexes
?uoride-BT43 complexes may be formed by the addition of
of BF3, provided the bond strength of the solvent BF3
a metal ?uoride to an ether-boron tri?uoride complex, fol
complex is less than the bond strength of the desired ?uo
lowed by liberation of ether. Fluoborates in comparison
with corresponding anhydrous metal ?uoride-B113 com 55 borate. To a degree this principle was recognized by the
teachings of the prior art. However, the only apparent
plexes are generally superior for use as curing catalysts or
as salts in plating baths. The metal ?uoride-BB com
plexes are unsuitable in that many of them break down
at room temperature, liberating BF3 and also in that metal
use which was made of this principle was to separate water
or others from their respective complexes with B133 in or
der to form metal ?uoride-B133 complexes. In contradis
tinction to this procedure, applicants’ invention is carried
out by employing an organic complexing medium which is
in water, the metal ?uorides being of no use in plating.
also a solvent for the desired ?uoborate. Applicants are
it is, therefore, an object of this invention to produce
therefore able to form, by means of the controlled addi~
a method for the preparation of anhydrous metal ?uo
tion of BF3, a crystallized meallic compound containing
borates.
it is a ?urther object of this invention to produce non 65 BF, radical.
The procedure of this invention necessitates a polar sol
aqueous solvated metal ?uoborates.
vent which will not break down to form dehydration prod
it is another object of this invention to produce a solu
ucts and which has some degree of solubility for the metal
tion of anhydrous metal fluoborate in an organic solvent.
We have now discovered that it is possible to produce
fluoborate formed. The term solvent as used herein is
anhydrous metal ?uoborates by the ‘addition of a metal 70 synonymous with the term coordinating agent, that is, the
fluoride to a solution of boron tri?uoride in an oxygen
solvent for the metal ?uoborate is also that compound
containing polar solvent which is not subject to a break
which forms a coordination compound with BF3. Some
?uoride-BPS complexes form metal ?uorides when placed
4
3’:
solvents which are suitable for the purposes of this in
vention are methanol and ethanol, methanol being pre~
ferred because it is a better solvent for metal fluoborates.
Speci?c examples of the preparation of anhydrous metal
amount of nitrogen was slowly added to 390 grams and
324 grams of crystals were ?ltered o?. B133 addition was
continued to 540 grams (total BR) and 611 grams of
crystals separated. The total yield ‘from above being 1001
grams of zinc ?uoborate crystals.
?uoborates according to this invention are as follows:
The crystals were
washed well with ether on a Bli‘chner funnel and dried
rapidly in a vacuum oven at 40° C. The crystals were
Example I
removed and packaged rapidly in glass jars with poly
393 grams of BF3 were added to 690 grams of methanol
ethylene liners. Total Zn analysis 14.9% ?gured to
in a 2-liter three-neck ?ask over a 11/2 hour period. An
Zn(BF4)2 is 54.4% by weight of product. This agrees
10
ice water bath was used to take ‘off the heat of reaction.
well with Zn(BF4)2.6CH3OH, theoretical Zn(BE4)2
‘One-half of the resulting solution was placed in each of
55.4%.
two l-liter Erlenmeyer ?asks containing 15 0 grams of
What we claim is:
Z11F2- The ?asks were stoppered and placed on an Eber
1. A process for the preparation of anhydrous zinc
bach shaker. Alcohol was added after shaking one day
?uoborate comprising mixing Zinc ?uoride with an anhy
15
to a total of 1090 grams of alcohol (including original
alcohol) ‘for dissolution of zinc ?uoborate crystals and to
enable good mixing. This was equivalent to a 36% solu
tion of BFa (plus Ell-7.; as SP3) in alcohol. The solutions
were allowed to settle 3 hours and the milky liquors
decanted into a dry 2-liter three~neck ?ask in an ice water
bath. 60 grams of alcohol insoluble Znliz were recovered
from the ?asks. A small ?ow of nitrogen was fed into the
?ask and BF3 impinged slowly on the surface of the liquor
while stirring slowly. _ 150 grams of BB, were added over
11/2 hours. This produced an equivalent of 17% BE, in
the BF3-alcohol (alcohol tied up in the solvated crystals
included).
The crystals were ?ltered on a Biichner fun
nel, washed with two 100 ml. portions of ether and pump
dried 4 hours to very slight loss in weight. 57.3 grams of 30
very hygroscopic solvated zinc ?uoborate crystals were
obtained. A higher yield could have been obtained upon
further addition of BF3 to about 25% BF3 in BF3-alocohl.
A large excess of BF3, however, was added to the liquor,
thus dissolving the crystals.
35
Example II
100 grams of BaF2 and 232 grams of CH3OH-BF3 solu
tion (33.3% BF3) were placed in a one-liter Erlenmeyer
drous 25% solution of ER in methanol, agitating the
mixture, removing unreacted metal ?uoride, adding addi
tional BFQ diluted by a small ?ow of nitrogen and ?lter~
ing off crystals of anhydrous Zinc ?uoborate.
'
2. A process for the preparation of an organic solution
of anhydrous zine ?uoborate comprising mixing zinc ?uo
ride with an anhydrous 25% solution or’ 13133 and methanol,
agitating the mixture and removing unreacted metal ?uo
ride.v
3. A process for the preparation of anhydrous barium
?uoborate comprising mixing barium ?uoride with an an
hydrous 33.3 % solution of BB, in methanol, agitating with
additional methanol, removing unreacted metal ?uoride,
adding additional B133, and ?ltering oil crystals of anhy
drous barium ?uoborate.
4. A process for the preparation of a solution of an
hydrous barium ?uoborate in an anhydrous organic solvent
comprising mixing barium ?uoride with a 33.3% solu
tion of BFB in methanol, agitating with additional meth
anol, and removing unreacted metal ?uoride.
5. A process for the preparation of an anhydrous metal
?uoborate comprising mixing a metal ?uoride selected
from the group consisting of Zinc ?uoride and barium ?uo
ride with a 5% to 50% solution of BF3 in an anhydrous
?ask. 249 grams of CH3O were added. The flask as stop 40 oxygen containing polar solvent, agitating the mixture,
pered and shaken for 3 days. The flask was allowed to
stand, the solution decanted into a one-liter three-neck
?ask in a cold water bath. BaF2 in the residue was 8.0
grams. 215 grams of B133 diluted by a small ?ow of nitro—
gen were run in with mild agitation. A large crystalline 45
precipitate was then ?ltered on a Biichner funnel.
The
BF3 addition was equivalent to 36% BF3 in BFg-alcoho-l
(alcohol tied up in solvated crystals included). 8P3 addi
removing unreacted meal ?uoride, adding additional BF3
and filtering o? crystals of anhydrous metal ?uoborate.
6. A process for the preparation of a solution of anhy
drous metal ?uoborate comprising mixing a metal ?uoride
selected from the group of zinc ?uoride and barium ?uo
ride with a 5% to 50% solution of BFs in an anhydrous
oxygen containing polar solvent, agitating the mixture
and removing unreacted metal ?uoride.
tion was continued to a total of 310 grams (44% BE solu~
‘tion in alcohol on original basis) for maximum precipita
tion. The salt was washed twice with 100 ml. portion of
anhydrous ether and pump-dried.
Example III
300 grams of zinc ?uoride were reacted for two days 55
with a solution of 393 grams of BF3 in 1179 grams of
methanol (25% EEK-methanol solution) in two one-liter
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,465,989
2,796,323
Sowa _______________ __ Apr. 5, 1949
Eberle _______________ __ June 18, 1957
814,638
Great Britain __________ _._ June 10, 1959
FOREIGN PATENTS
OTHER REFERENCES
Erlenmeyer ?asks. Constant agitation was maintained on
I. W. Mellor’s “A Comprehensive Treatise on Inorg.
‘an Eberbach shaker. The liquor Was decanted into a
two-liter three-neck ?ask in an ice water bath. 23 grams 60 and Theoretical Chemistry,” vol. 5, 1924 Ed., page 123,
pf zinc fluoride residue remained. 3P3 diluted by a small
Longmans, Green and Co., NY.
s.
UNITED STATES PATENT OFFICE
CERTIFICATE OF CORRECTION ‘
Patent No‘, 3,018,,162
January 23‘, 1962“
Harold S, Halbedel et al.,
It is" nerebyoer’oifmd that error appears in ,the above numbered pat
entrequiring correction and‘bhat the, said Lettersv Patent should read as
"corrected below.
Column 2, line 63a for "meallic‘" read -- metallic: "—¥~';'
column 3‘I line 32", "-alocohl" read -—— —alcohol “a; line 40‘z
for "CH3O" read --.CH3OH -=-—; column 40 line ill‘z for "meal"
read
——
metal
—-—.
'
Signed and Sealed this 8th day of May 1962;.
(SEAL)
Attest:
ERNEST W. SWIDEE
Attesting Officer
DAVID L. LADD
Commissioner of Patents