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Патент USA US2135460

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Patented Nov. 1, 1938
i 2,135,460
0
UNITED STATES PATENT
OFFICE '
2,135,460v
PREPARATION OF BORON FLUORIDE
Donald J. Loder,‘ Wilmington, Del., assignor to
E. I. du Pont de Nemours & Company, Wil
mington, Del., a corporation of Delaware
No Drawing. Application August 5, 1936,
Serial No. 94,337
8 Claims. (01. 23-88)
This invention relates to- a process for the After the removal of the water by distillation or
' preparation of boron-halogen compounds and
other means there remains the metal halide
_more particularly to the preparation of boron boron-halogen complex. If the metal halide em
?uoride.
5
_
‘
ployed is an alkaline earth halide or an alkaline
-
An object of thepresent invention is to provide ,earth salt or oxide, such, for example, as calcium 5
a process for the separation of constituents from
complexes containing the same and more partic
ularly to the separation of boron ?uoride from
its complex. Another object of the invention is
10 to provide a process wherein a boron-halogen
- containing compound is separated from its com
plex with water.
A further object of the inven
tion is to provide a process wherein an alkaline
earth metal halide is added to a complex, com
- 15 pound, mixture, or solution of water and- boron
I
carbonate, calcium oxide and the like which re
act with a boron halide to form an alkaline earth
halide, the boron-halogen constituent can be ob
tained in a substantially anhydrous ~form by
simply heating the complex to a temperature of 10
from 150 to 300° C.
,
The metal halides ‘which have been found par- ,
ticularly well adapted for replacing water from
complexes containing them and a boron-‘halogen
containing compound include, for example, cal- 15
?uoride; the water is removed and the boron lcium'?uoride, zinc ?uoride, aluminum ?uoride,
?uoride recovered in the anhydrous form. A aluminum chloride, cuprous chloride, lead chlo
more speci?c object of the invention is to provide rlde, iron chloride, tin chloride, calcium chloride,
a process wherein complexes containing boron ‘barium chloride, and analogous metal ?uorides,
20~ ?uoride, and water may be so treated that the chlorides, bromides, and iodides. While metal 20
anhydrous boron ?uoride is freed from the water. halides will replace the water in a complex con
Other objects and advantages of the invention taining it and a boron-halogen constituent, such
will hereinafter appear.
_
I have found that if a boron-halogen-water
as boron tri?uoride', I have found in addition that
the alkaline earth halides and more especially
the alkaline earth ?uorides form a complex or 25
25 complex, compound, mixture, or solution is
treated with a metal halide the water will be set - compound with boron ?uoride from which the
free, leaving a compound formed between the boron ?uoride or other analogous, easily volatil
metal halide and the boron-halogen constituent. ized, halogen-containing compound may be re
Moreover, if alkaline earth metal halides are covered by heating. The alkaline earth halides,
80 employed, the alkaline earth metal halide-boron such, for example, as the ?uorides, chlorides, and 30
halide reaction product will, upon heating, give bromides of calcium, barium or strontium, and
up the boron halide it contains leaving the alka
salts thereof which react with boron halides to
line earth halide as a residue. Accordingly when
form alkaline earth halides likewise have the
employing alkaline earth ~metal halides it is ability to not only displace the water from its
36 possible to recover the boron-halogen-contain
complex with a. boron halide, but also to permit 35
ing constituent from water.
>
the recovery of the boron halide from the alka
Boron ?uoride, and analogous boron-halogen line earth halide.
‘The advantages of my process for the prepara
compounds, form with water and other com
pounds an association that has been generally tion of anhydrous volatile halides from complexes
40 called in the literature a “complex.” In this containing them' can I be readily appreciated. 40
" speci?cation and the claims appended thereto. For example, hydrated boron ?uoride can be
this association will be referred to as a “complex” prepared by interacting anhydrous hydro?uoric
altho this term will be understood to‘ include acid with solid orthoboric. acid, boric anhydrides
‘ water and a boron halogen compound whether
45 they‘rare present as a solution, mixture, com
pound, or complex, or whatever maybe the man
ner of their association.
'
Generally, my‘ process is effected in the follow
ing manner; a metal halide is added to the com
50 plex containing water and a boron-halogen con
stituent and apparently due to the fact that
the boron-halogen constituent reacts more readily
with the metal halide, a complex is preferentially
formed between the metal halide and the boron
55 halogen constituent, thereby freeing the water.
or borates.
The reaction may be effected by the
addition of the anhydrous hydrogen ?uoride to 45
' the solid orthoboric acid, boric anhydride or
borate which comprises essentially a vhydrated
boron tri?uoride. To this product calcium ?u
oride is added, water is liberated and can be re
moved by a simple heating operation to a tem- 50
perature of about 110° C. thereby leaving as a
residue a'compound. containing calcium ?uoride
and boron ?uoride. By heating this substan
tially anhydrous material to a higher tempera- .
ture, say form 170 to 500° 0., usually a tempera- 55
. ture of 250° C. is sumcient for satisfactory‘ recov
-.ery, the boron ?uoride can be driven off in a sub
stantially anhydrous form leaving calcium ?uo
ride as the residue.
I shall now illustrate by way of examples meth
ods of preparing boron ?uoride from various com
plexes containing it but it will be distinctly under
stood that the invention will not be limited spe
10
ci?cally to the details of the examples.
Example 1.—-121.8 grams of (HzO)a.BF: (1
mol) is treated with 45 grams CaF: (.58 mol) in
a ?ask‘ attached to a short fractionation column.
The mixture is heated in an oil bath to not more
than 150° C. at one atmosphere pressure, during
15 which the water and a small amount of boron
?uoride is distilled out. The distillation can be
effected at atmospheric or reduced pressures.
densing agent can be recovered and used over
and over again the sole loss in catalyst occurring
from usual physical operating causes rather than
from loss due to by-.product formation.
From a consideration of the above speci?cation
it will be appreciated that many changes may be
made in the process herein described without
departing from the scope of the invention or sac
ri?cing any of the advantages that may be de
rived therefrom.
.
I claim:
_
1. In a process for the preparation of boron
?uoride and steps which comprise reacting a
metal halide with a water-boron ?uoride complex
and subsequently separating from the resulting 15
metal halide-boron ?uoride complex the boron
?uoride..
.
.
-
2. A process for the preparation of boron ?uo
consists mainly of Ca(BF4) 2, totemperatulres be- I ride which comprises reacting a compound se
lected from the group consisting of an alkaline
tween 300° C., and 500° 0., resulted in the evo
lution of boron ?uoride according to the equa
earth halide and an alkaline earth salt that will
Subsequent heating of the solid residue, which
25
tion: Ca(BF4)z—>CaFz+2BF3. Temperatures be
form a halide when reacted with a boron halogen
low and above those given may be used but the
compound with a water-boron ?uoride complex
range given is preferred.
and subsequently removing from the resulting
Example 2.—-51.9 grams of (H20) z.BF':'(.5 mol)
is treated with 25 grams NaF (.6 mol) in a. ?ask
complex the boron ?uoride in a substantially 25
attached to a short fractionation column. The
. mixture is heated in an oil bath to approxi
mately 150° 0., during which time water is
The distillation can'be conducted at
30 evolved.
atmospheric or reduced pressures. The BF:
can be recovered by heating the solid, which con
sists mainly of NaBFi, to higher temperatures. 7
anhydrous form.
'
3. A process for the preparation of a boron
?uoride which comprises reacting a boron ?uoride
associated with water with calcium ?uoride, heat
ing and evaporating the water from the result
ing mixture, and subsequently, at a higher tem
perature driving off the boron ?uoride.
4. A process for the preparation of boron ?uo- '
. Example 3.—About 60.9 grams (H2O) 3.]3Fa (.5
mol) was treated with 60 grams NaCl (1 mol) in
a ?ask attached to a short fractionating column.
The mixture was heated in an oil bath to not
ride which comprises reacting a complex of water
and boron ?uoride with calcium ?uoride, heating 35
and evaporating the water from the resulting
solid residue (NaCLBFa) by further heating to
ing and removing all the water, and subsequently,
mixture, and subsequently, at' a higher tempera- ‘
more than 150° C., to drive off the water. The‘ ture driving off the boron ?uoride.
distillation can be carried out at atmospheric or
5. A process for the’ preparation of boron tri-.
40 reduced pressures.
.
?uoride which comprises reacting a water-boron
The boron ?uoride can be separated from the tri?uoride complex with calcium ?uoride, heat
from 300-500" C.
-
If desired the condensate obtained by heating
45 the mixture containing the water, boron ?uoride,
and a metal halide can be distilled to give a resi
at a higher temperature, driving oil the boron
tri?uoride.
.
6. A process for the preparation of boron tri
?uoride which comprises reacting a mixture con
due containing substantially all of the boron' taining one'mol of a boron tri?uoride water com
?uoride originally present in the condensate.
This residue may be combined with the next
50 batch of water-boron ?uoride to be treated there
plex with approximately one-half mol of calcium
?uoride, heating and removing the water and
subsequently, at a higher temperature, driving
by providing a method of substantially complete '
01! the boron tri?uoride.
recovery of the‘boron ?uoride..
7. In a process for the preparationvoi' a boron
?uoride the steps which comprise reacting a com
My' process is particularly vwell adapted for
use in separation of a boron-halogen constituent
55 from addition compounds containing it and water
and more particularly such addition compounds
in which the halogen constituent is a highly vola
tile halide, such, for example, as‘ the ?uorides,
chlorides,-bromides, and iodides of boron. Cal
60 cium ?uoride is particulary well adapted for use
in a process for separating not only- the water
from a water-boron ?uoride complex, but to
separate the calcium ?uoride-boron ?uoride
complex-formed into boron ?uoride and calcium
65 ?uoride. It will be appreciated that when em
ploying boron ?uoride as a condensing agent in
organic acid reactions the use of calcium ?uoride
is particularly useful for the reason that the con
'
'
pound selected from the group consisting of anv
alkaline earth metal ?uoride and an alkaline 55
compound that will form a ?uoride when reacted
with a boron ?uoride, with a water-boron ?uoride
complex andsubsequently separating from the
resulting metal halide-boron ?uoride complex the
60
boron ?uoride.
8. In a process for. the preparation of a boron
?uoride compound the steps which comprise add- ‘
ing an alkaline earth metal halide to a. water-'
boron ?uoride complex and subsequently sepa
rating from the resulting alkaline earth metal
halide-boron ?uoride complex the boron ?uoride
by heat.
DONALD J. LODER.
‘CERTIFICATE OF dbRREcTIoN.
Patent No° 2,l55,h60, '
'
"
November- 1, 1958.,
DONALD J. LODER.
'Itis hereby certified that error appears in the printed specification
of the above numbered patent requiring’ correction he follows: Page 2,7 second
‘ column, line '15, claim 1, for the word "and" read the; and that the said
Lettere Patent shouldbe read-with this correction therein that the same
may conform to the record of the case in the Patent Office“
‘Signed and sealed this 20th day of December,7 A. D. 19580
‘Henry Van Aredal‘e
(Seal)
Acting Commissioner of Patents.
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