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Патент USA US2131925

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ammo... 4, 193a
_ 2,131,925
I ‘ I
j; a‘ssignor.‘ tolrE.“ J m
‘ I. du PontdeNemours & Company, Wilming-l
I , ‘ton, Del.,“a_ cor-notational‘ Dchwvarev
‘ ‘a
w No
Application‘Fcbruary 6, 1937;,1
‘ ~Serial No. 124,524'
‘_ aoiaim.‘ (cute-70a)
3‘ a v ‘ This‘invention relates ‘to aiprocess for ‘purifying
, ,
,‘ 9
methyl phthalate, diethyl phthalate, dimethyl cel
organic “compounds and more" particularly ‘to-the ‘losolve phthalate. and dibutylphthalate which are
‘removal; off‘cont‘a‘n'iinants‘ from‘ organic‘ liquids? ‘ fv {commonly . used . in ‘ a‘ the I manufacture of. trans
parent cellulose. derivative sheeting that ‘forms
‘ ‘commonl‘y'us‘ed
In the preparation‘oi‘
in?‘ the preparation
oi’ lacquers.
for certain y one‘ or the laminations‘ inqsaiety» glass“ must“ ‘be ‘
‘ purposes,particularlyinthe ‘safety glass industry, ‘f‘water-white” ‘and ‘must remain in thiscondition ‘
‘it is essential that “ the lacquers remain clear for‘ ‘ for extended ‘periods ‘of time. Ordinarily, this is
‘prolonged periods of time.‘ It has been IOlll'idr accomplished bypassing the ester‘through acti;
that this can be accomplished to some extentpby _' vated carbon. After the liquid‘isv passed through, i
‘ .
‘i 1‘ I bringing the‘ liquid ingredients in contact with
activated‘carbon. ,When' this is done, however,
certain contaminants ‘are imparted to the liquid
‘ ‘
‘ ;
presumably from the carbon. Cellulose derivative
‘adhesive or lacqueri?lms produced from composi
‘18 tions in which such liquids have been used as sol
vents or‘ diluents are very“ apt to develop dark
blemishes or stains in‘time. Such stains are not
‘ particularly objectionable in colored lacquers or
i ‘
‘ in adhesive ?lms which arenot seen; but, where
it is usually "water-white” but it has been found 10
that for some reason this treatment aggravates
the‘ tendencies toward discoloration with the pas
sage of time. ‘ The foreign material present in the
ester whether absorbed or whether present ini-'- -‘
‘tially usually amounts to less than 0.1% of the
weight of; the ester. A complete analysis or the
foreign‘ matter is relatively di?icult ‘due to the
amounts in which it is present. It has been found
that at least part of this material contains sul- ’
‘ ~‘ 20 they ‘are used to join the laminations of safety . phuneither in=the elemental form or combined
as mercaptans. However, the material which is
‘ ’ glass, adhesives or‘ lacquers so produced are un
‘ satisfactory.’ jMany chemical ‘methods have been
responsible for the ‘subsequent discoloration oi
i , proposed‘for the removal‘ of such contaminants the cellulose derivative ?lm may be removed by
“ ‘ ‘ whétherthey‘were imparted ‘tothe liquid through, , shaking the liquid with about 5% of its weight of‘
“ 25 the ‘activated. carbon or in their ‘initial ‘prepara-; powdered lime. This treatment is usually carried
out at a‘temperature of about 80° C. to 90° C., for
,tion.‘ Among the proposed methods are the treat
' ment of such liquids with copper, mercury,‘ or" ' about two hours. Insome cases, less time is re
‘zinc in the powdered form‘; These are not satis- _ quiredand in others more time is necessary. ‘ An
‘factory for the reason that a very‘long time is, _ approximate indication of a satisiactorylength‘ of
required for thetreatment oi the liquids.
I ‘ Another methodfwhich has been proposed in
time for treatment may be obtained by adding
a drop of mercury to the‘ treated ester; If the
volves blowing the organic liquids with a current ‘mercury remains bright, the treatment‘ has been‘ ,
of air.; ,This‘ method is not practical for the rea-‘ suf?cient. If it tarnishes or is otherwise discol-“
son thatla'larg'e amount of .vapor‘ is carried away ' ‘ored, the treatment should :be prolonged.
35 ‘and ‘its recovery is thereby necessitated. If. the
temperature‘is increased to shorten the time of
_ blowing, an‘increase ‘in color‘and acidity is in
“ variably produced; .Thepresent invention'has as
“*3 ‘ an object the provision of a. method of removing
‘4° contaminants ,irom lacquer ingredients which is
cheapand e?lcient. ‘A further object is a process
lime is usually in the form’ of ‘CaO‘; that is, quick 35
When used in this form, any traces of
water will be removed aswell as any‘ free acid.
The lime may then be removed by ordinary ?ltra
V lime.
tion and the liquid is ready for use.
The invention is not restricted to the puri?ca- 1
tion of the esters mentioned above, but is adapted
.for removing contaminants from‘ organic, liquid‘ to the treatment of other such esterswhich are
‘ “solvents,ldiluents,f and plasticizers for cellulose ‘solvent plasticizers for cellulose derivative ?lms.
“ ‘
‘ derivative lacquers'which have been treated with ‘ In addition to liquids of this class, other com— ‘
‘r 45 activated‘charcoal. “A still further object of this ‘ pounds such as diluents; for example,inaphtha, 45
‘ “
invention isthe provision of a method which not xylene, kerosene, gasolines, and other aliphatic
only removes contaminants, but neutralizes and and aromatic hydrocarbons may be treated‘with
dries organic‘ liquids in a ‘simple and‘expeditious ‘ success. It has also been .found‘ that solvents
such as the lower alkyl acetates, alcohols, eta,
Otherbbjects will be apparent as the
“ a manner.
may be, purifiedas indicated above. ‘When low '
‘ 50‘ description of“ the invention proceeds.
‘ ‘
These objects‘ are obtained according to the
boiling liquids of this class are treated, the tem
present invention by treating the organic liquids
perature'is not raised to 80° C. or 90° C., but is
under certain conditions.
When the‘ process is applied to hydrocarbons, ‘
it may be necesary‘to raise the temperature above 65
‘ of the class mentioned above with powdered lime 1 carried out at about room temperature.
“ 65"" As suggested above, plasticizers suchcas di
the range indicated above. For example, in the
purification oi kerosene, it has been found that
it is necessary to heat the mixture to about 125°
C., to obtain the desired results within a reason
able time. In the treatment oi‘ most hydrocar~
bons, however, lower temperatures were satis
While it has been indicated that 5% of lime
based on the weight oi’ the liquid treated is usu
10 ally suiiicient, it will be obvious that where the
percentage of contaminants is unusually high or
there is considerable acid or, moisture present in
the liquid it is necessary to increase the percent
age of lime. In any event, whether the lime is
increased or whether the liquid is subjected to
repeated treatments, the test with mercury will
indicate when the liquid is free from contami
nants. This test is extremely sensitive.
While it has been indicated that quick lime is
preferred, the process may also be carried out with
slaked lime.
It will also be. apparent that other oxides or
‘hydroxides having the same action may be used.
The process herein describedis very simple and
inexpensive and results in the preparation 01' cel
lulose derivative ?lms-which retain their trans
parency and clearness for inde?nitely long pe
riods of time. Such, cellulose derivative films are
particularly adapted for use in the production of
safety glass. The liquids so treated are also
adapted for use in other clear cellulose derivative
compositions such as adhesive lacquers and the
like whether colorless or colored. Colored lac
quers prepared from treated liquids retain their
brilliancy and pure color.
It is apparent that many widely different em
bodiments oi’ this invention may be made without
departing from the spirit and scope thereof; and,
therefore, it is not intended to be limited except
as indicated in the appended claims.
I claim:
1. In the process for purifying colorless organic
liquid solvents, plasticizers, and diluents for lac
quers wherein the’ liquid is decolorized with acti
vated carbon the improvement which comprises
agitating the liquid with about 5% of its weight
of powdered quick lime at a temperature of 80° C.
_to 90° C. for about two hours.
2.1?rocess for purifying liquid phthalic acid
esters, whereinthe ester is decolorized with acti
vated carbon, the step which comprises agitating
the ester with about 5%‘ of its weight oi.’ powdered
lime, at a temperature of about 90° C., for about
two hours.
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