Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
A ~ ~ ~ ~ Express Mail Certificate No.:
U ~ B10080433
DOC~ET NO.: P~523
Process for Preparing Hydrophobically
Modified Guar Ethers
Cross Reference
This application is related to U.S. Patent No. 4,870,167,
which issued September 26, 1989.
Back~round of Invention
The field of art to which this invention is directed is
polysaccharide derivatives.
Polygalactomannans and the~r derivatives are well known
compositions which have many uses as thickening agents in aqueous
systems.
Guar gum is a polygalactomannan which essentially is a
straight chain mannose with single membered galactose branches.
The rat o of galactose to mannose in the guar polymer is 1:2.
A~kyl ethers of guar gum have been made by reacting guar
spl-;s with an alk ha ide or an aik~ylene oxide. Guar gu~
~apl-ts a~Q obta ned af~er the removai of the hulk and t;e gums
from guar seeds. Generally, the guar gum splits are mixed with
suf'icient water and aiXal to swel' the splits but insuf_:ic:ent
to form a gel. The alkyl haiide or the alkylene oxide is then
added and the reaction is conducted under agitation, usua;l~ in
an apparatus, sucn as a ribbon blende_. When the reaction `~
complete, the guar reaction product, still in particulate for~ is
washed to remove excess alkal-, salt or other by-products. The
guar gum derivative i3 then dried and flaked or powdered.
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aydrophobically modified non-ionic guar gum is disclosed in
our patent, U.S. 4,870,167. The process as described in the
patent involves reacting a hydrophilic guar derivat ve, e.g.,
hydroxypropyl guar, with a long chain hydrocarbon epoxide or
halide using an organic l-quid in the process.
Hydrophobically modified guar gum is disclosed in European
Patent Application No. 323,627.
Hydrophobically modified non-ionic cellulose ethers are
described in U.S. Patent No. 4,228,277.
Summarv of Invention
This invention is directed to a process for preparing guar
gum hav ng both h~drophilic and hydrophobic substituents. In
particular, this invention pertains to a process for
manufactur-ng hy~rophilica'ly-hydrophobically modified gua- gu~
directly from guar bean splits.
By the process of this invention, guar gum derivatives a-e
made hav~ng both hydrophilic ether substituents and hydrophobi-
ether subst tuents wherein the hydrophilic ether substituent ;s
selecteZ from the group consisting of RC ~nd HOR10, wherein ~ s
an alkyl groLp containing one to four car~on atoms, wAerein R ~s
an alkylene group containin~ two to four carbon atoms and wherein
the OH grou~ ~s on the carbon atom beta to the et~er group,
wherein the hydrophobic ether substituent is selected from the
group consisting or R20, HoR30, and
R OCH2CHCH20
OH
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wherein R2 is an alkyl group containing about 8 to about 28
carbon atoms, wherein R3 is an alkylene group containing about 8
to about 28 carbon atoms having the OH group on the carbon atom
beta to the ether group, and wherein R is an alkyl group
conta~ning about 5 to about 25 carbon atoms.
By process of this invention, guar bean splits are reacted
first with an alkyl halide, RX, or a 1,2-alkylene oxide,
represented herein as Rl=O, wherein R and R1 are the same as
described hereinabove, to form the hydrophilic substituents under
aqueous alkaline conditions us ng sufficient water to swell the
guar bean splits but not to dissolve them. Without removing water
or by-products, the hydrophically substituted guar splits are
then reactec. with a long chain alkyl halide, R2X, a long chain,
1,2-epox_de, R3=C, or a long cha-,n glycidyl ether, R OC~2 CH-CH2,
wherein R , R and C
R4 are the sa~e as described hereinbefore to form the hydrophob__
substituent, wherein the long chain ha' de, epoxide or gl~c d~l
e'ner ls addea as a solution in an organic solvent whic~ s
cayabie of swe'lina .he hydroohica'l~ subst tuted guar but nct
dissoiving it. Suff;cient hydrophilic derivatizing agent is used
to ob~a n a M.S. of abollt 0.2 to about 2. Sufficient hydrophob~c
derivatizing agent is present to obtain a M.S. of about 0.001 to
about 0.2. When the derivatiz ng reaction is complete, the guar
product is washed with water to remove by-products and unreacted
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reagents and is dried to a moisture content below about 10
percent by weight.
Description of Invention
The guar used in the process of this invention is in the
form of "splits. n Since the guar bean or seed is dicotyledenous,
two endosperm halves are obtained from each seed. These
endosperm ha'ves surround the embryo, and they in turn are
surrounded by a hull. The endosperm halves are separated from
the hull and embryo by taking advantagè of the difference in
hardness of the various seed components. Multistage grinding and
sifting operations are combined with other physical treatments to
crack the seeds and separate the parts. The separated endosperm
halves are referred to in the trade as "spllts~.
~ he hydrophil1c de~ivatizing agent used in this invention ls
an alkyl halide or alkylene oxide wherein the alkyl grous
contalns 1 lo 4 carbon atoms and the alkylene group contains 2 tc
4 ca-bon atoma. Examples of such der vatizing agent~ are methyl
ch!or'de, ethyl bromide, methyl iodide, ethylene ox_de,
1,2-?ropy'ene oxide, ;,2-butylene oxide, and 2,3-butvlene cx-'de,
or mix~ures ~hereof,
The hydrophobic derivatizing aqent used in this invention ~s
a long aliphatic cha'n epoxy compound which contains from abcut c
to about 2~ carbon atoms or an alkyl halide havin~ about 8 to
about 28 carbon atoms in the alkyl group. Examples of such epox~
compounds are 1,2-epoxyoctane, 1,2-epoxydodecane;
1,2-epoxyhexadecane, l, -epoxytetracosane and the like. Other
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long chain epoxy compounds are glycidyl ethers of aliphatic
alcohols wherein the aliphatic alcohols contain about 5 to about
25 carbon a~oms. Examples of such glycidyl ethers are the
glycidyl ethers of amyl alcohol, hexanol, octanol, lauryl
alcohol, stearyl alcohol, lignoceryl alcohol and the like.
Examples of useful alkyl hal~des are octyl chloride, decyl
bromide, dodecyl iodine, hexadecyl bromide and the like.
The alkaline catalysts used in this invention are alkali
metal hydroxides, e.g., sodium or potassium hydroxide.
In carrying out the process of this invention, the guar
splits are added to a reactor along with water and the alkaline
catalysts. Suffic7ent water is added to be imbibed by the splits
and to swell them, but insufficient to dissol~e the splits. It
is impor~ant that the guar splits retain their particulate form
and to not merge together to form a gelatinous mass. The amount
of wa.e~ added to the reactor will vary from about 30 to about
~50 par_s b~ welght of water to 100 parts by weiaht of guar.
Preferably, this amount of water will be about 75 to about 1
parts of ~-ater to 100 parta of guar.
The alka i metal hydrox~de is used in catalytic amounts, or
if an aikyl halide is used, in amounts equivalent to the halide
plus a catal"tic amount. The catalytis amount of alkali meta'
hydroxide used is about 1 part up to about 50 parts by weight pe~
100 parts by weight of guar splits, and preferably about 3 to
about 10 parts per 100 parts of guar.
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The alkaline catalyst is used in the process of this
invention as an aqueous solution. It can be added as a solid to
the reactor and dissolved in the water used in the process prior
to the add~tion of the guar splits. Preferably, it is added to
the reactor as an aqueous solution.
Air is then evacuated from the reactor and is replaced with
an inert gas, e.g., nitrogen. A low shear mixing or tumbling
type of agitation is used throughout the derivatizing reactions
so as to contlnually expose the surfaces of the guar particles to
the derivatizing agent and to keep a uniform temperature
throughout the reactor without exerting shearing forces on the
particles so as to grind or smear them.
The hydrophilic derivatizing agent is then introduced into
the reactor and the temperature is controlled between about 100F
to about 250F, preferably about 160 to abut 200F.
The hydroph~lic derivatiz ng agent is used in an amount
sufficien~ to obtain the M.S. speci'ied hereinbefore, i.e., about
0.2 to about 2 and preferably, about 0.3 to about 1.2. The
amount of de_ivatlzing agent to be used c~n readily be deter~ined
by those skilled in the art by running controlled experiments and
analyzing the product. Generally the amount of de_ivatiz~ng
agent w ll var~ from about 20 to about 350 parts of hydrophllic
derivatizing agent to 100 parts by weight of guar and preferably
about 25 to about 100 parts by weight.
The reaction with the hydrophilic derivatizing agent is
conducted for a time sufficient to obtain the desired M.S.,
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generally about 30 minutes to about 3 hours.
When the hydrophilic derivatizing reaction is completed, the
reaction with the hydrophcbic derivatizing agent is then
conducted without isolating the product of the first reaction.
The hydrophobic derivatizing agent is added to the reactor
as a solution in an organic solvent, wherein the solvent is or.e
which can swell but not dissolve the guar derivative. The
solvent is one which is miscible with the hydrophob_c
derivatizing agent, wh,ch is miscible with water in the amount of
at least 10 weight percent water-in-solvent or solvent-in-~-ater,
and which has a solubility parameter greater than 4.5 (J~m3)1'2 x
-3
. Solubility parameter is described in detall in
Kirk-Othmer, "Encyclopedia of Chemical Technology," 3rd Editicn,
Volume 21 (1983~ beginn'ng at page 377, wh_ch is here_y
incorporated by reference. Examples of suitable solvents a_-,
l-propanol, 2-propancl, t-butanol, propvlene ox-de,
tetrahydrofuran, dimethyl sulfoxlde, N,N-d~met~yl formam_~e.
methanoi, ethanol, ethylene glycol, ethylene glvcol monome~
ethe~, ethylene glycol mcnobutyl ether, propylene g'-yco:,
propylene g'ycol monomethyl ether, propylene gl co mcnceth;l
ether, diethylene glycol monoethyl ether, methyl ethyl ke~one,
and acetone. Preferred solvents are the solvents which conta~n
an aliphatic hydroxyl group, with the more preferred be~`ng
secondary or tertia_y hydroxyl groups. The most prefer~e~
solvent is 2-propa~ol~ The amount of solvent used is at leas~
equal to the weight of the hydrophobic derivatizing agent, up to
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about 10 times its weight, preferably about 2 to about 5 times
its weight.
The amount of hydrophobic derivatizins agent used is that
amount which produces a M.S. as referred to hereinbefore, i.e.,
about 0.001 to about 0.2. The amount of hydrophobic derivatiz ng
agent to be used can be determined readlly by those skilled in
the art by running controlled experiments and analyzing the
product. Generally, the amount of derivatizing agent will vary
from about 1 to about 50 parts by weight based on 100 parts by
weight of guar splits originally reacted, and, preferably about 5
to about 20 parts by weiqht.
The reaction w-th the hydrophobic derivatizing agent is
conducted at a temperature of about 100F to about 250F,
preferably, about 160F to about 200F for a sufficient time to
complete the reaction, generally about 1 to about 4 hours~
The hydrophilic, hydrophobic guar derivative still in
par~icu'a e ~crm is washed wl_h water, to remove q'ycol
by-producls, alkali metal hydrox des, organ c solvents and salts
wn le remc~_ng a minimum of the derivatized guar. The wash ns
c~n be conducted by siurrylng and decant ng, or bv
counter-current extraction, processes well known to those sk lled
in the art. The excess water s removed, e.g., by
centrifugation, and the product is then dried to a moisture
content below 15 weight percent, preferably below 10 weight
percent. ~he drying processes can be conducted with a drum
dryer, a hammer mill using heated alr, or n an oven followed 'ay
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grinding. A preferred method is "flash grinding~ whereby as the
product is ground, the moisture is evaporated. The water can
also be removed using organic solvents, such as those described
hereinabove for use in the hydrophobic derivatization. The
derivatized guar product is ground to a particle size of less
than about 20 mesh (U.S. Standard Seive~ and, preferably less
than about 80 mesh.
In carrying out the process, small amounts of borax or
aluminum salts can be used to complex the surface of the guar
particles, thereby facilitating the washing and drying processes
which are well known to those skilled in the art.
The follow_ng examples describe the invention in detail.
Parts and percentages are by weight unless otherwise designated.
Example 1
To a suitable reactor were added 1800 parts of deionized
water, 200 parts of a 50 percent aqueous solution of sod-um
hydrox de an~ 5 par~s of borax. Agitation was begun and the
temperat:lre ~as raised to 180F. Doubie pur'ried guar spl._s,
2000 parts, were then added and the reactor was evacuated and
purged three times w~th nitrogen. A vacuum of -10 inches of Hg
was applied, and introduction of 1500 parts of propylene oxide
was begun and continue~ over a period of 1 hour and 30 mlnu~es
while keeping the temperature at 170-176C. The temperature W39
then lowered to 85~F and a vacuum of -5 inches of Hg was applied.
A solution of ,00 parts of 1,2-epoxyhexadecane in 500 par_s or
propylene oxide was added and held at 85F for 1 hour. Heat was
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then applied raising the temperature to 170 F. This temperature
was held for 2 hours. Borax, 10 parts, in water, 250 parts, was
added and the temperature was lowered to 110F. The reaction
mass was discharged from the reactor.
The discharged product was washed twice with water (10 parts
to 1 part of guar originally added to the reactor) and was
centrifuged to a ~oisture content of 66.9 percent. The product
was then dried and processed through a hammer mill at an air
inlet temperature of 550F, outlet air of 275 F. The resulting
product had a moisture content of 7.8 percent and an average
particie s ze of less than 150 (U.S. Standard Sieve).
To a suitable reactor were added 1800 parts of deionized
water, 300 parts of 50 percent aqueous sodium hydroxide, and 7
parts of borax. Heat was applied rais~ng the temperature to
180F. DOUD'e purified guar splits, 2000 parts, were then added.
The reactor was e~acuated and purged three times with nitrogen,
the temperature was adjusted to 140F, and a vacuum of -10 nches
of Hg was appl_ed. The addition of 1500 parts of propy'ene ox-de
was begun and tne temperature wa3 raised to 180F. The add_tion
of propylene ox_de was completed in 1 hour and 52 minutes. The
tempera~ure was then lowered to 140F and a solution of 150 parts
of l,.-epoY~yhexadecane in 500 parts of lsopropanol was added.
~fter 30 mlnutes at 140F, the temperature was raised to l~OaF
and was held at this temperature for 2 hours. The temperature
was lowered to 110F and the reaction mass was discharged from
the reactor.
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The reaction mass was washed twice with water (10:1 by
weight) and was centrifuged to a moisture content of 66.8
percent. The product was then milled and dried in a hammer mill
with an ai~ inlet temperature of 480F and an outlet temperature
of 240F. The product had a moisture content of 6.7 percent and
an average particle size of less than 150 mesh (U.S. Standar~
Sieve).
Example 3
Using the same procedure described in Example 2, a reaction
was conducted with 2000 parts of double pur fied guar splits,
1800 parts of deionized water, 300 parts of 50 percent aqueous
sod~um hydrox de, 7 parts of borax and 1500 parts of propylene
oxide, foilowed by reaction with 150 parts of i,2-epoxydecane in
500 par's of _sopropanol. The resulting product had a moisture
content of 5.6 percent and an average particle si2e of less than
150 mesh.
Exampie 4
To a su table reactor were added 1760 parts of deionized
water, 168 parts of a 50 percent aqueous sodium h~drox_de
solution and ~ parts of borax. The temperature was ra.sed '~
180F and 2000 parts of double purified splits were added. The
reactor was evacuated and purged 3 times with nitrogen ar.d
nitrogen was added to a pressure of 10 psig. A~ter holding the
pressure for 10 minutes, the temperature was adjusted to lfiO~
and the reactor was evacuated to -10 in hg. The addition o~ i60
parts of butylene oxide was begun and continuing over 1 hour and
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30 minutes with the temperature rising from 161 F to 178F. The
temperature was lowered to 140F, at which point a solution of
150 parts of l-epoxyhexadecane in 500 parts of isopropanol was
added. After holding at 140 F for 30 minutes, the temperature
was raised to 170F and was held for 2 hours. The temperature
was then lowered to 78 F. The product was discharged from the
reactor and was washed twice with water at 10 to 1 water to
initial guar ratio. The washed product was centrifuged to a
moisture content of 68.4 percent and was then milled using inlet
air of 550F. The resultlng product had a moisture content of
8.9 percent and an average mesh size of less than 150 (U.S.
Standard Sieve~.
Example 5
Half percent so'utions of the derivatized guar from rxamples
1 to 4 were made in deicn zed water. The p~ of the solutions was
adjus,ed to 6.~ w~th hydrochloric acid. The solutions were
stirr2d for one hour. To 400 parts cf each solution were added a
28 percent solution of ammonium lauryl sulfate (AL~ in wa'er.
The viscosity was then determined uslng a Brockfield viscometer
at 20 RPM. After each viscosity determination, addi~ona'
ammonium lauryl sulfate was added and the viscosity was
determlned after each addition~ The viscosity determination and
the amount of ammonium lauryl sulfate are shown in the ~able.
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Table
Example 1 2 3 4
ALS - partVISC V_Sf VISC V SC
cps cps cps cps
0 155 720 520 394
0.2 1400
0.4 300 2300 1032
O.S 300
0.8 1250 4300 4 05
1.0 960 5700 700 6210
1.2 720
1.25 6600
1.4 8320
1,5 10,0007920
l.fi
1.75 ~10,~00
2.. 1>10,000 491
2.~5 >10,000
2.5 >10,0~0
2.75 28~0
3.0 lcOO 5000
3.5 700
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The principles, preferred embodiments and modes of operation
of the present invention have been described in the foregoing
specification. The invention which is intended to be protected
herein, however, is not to be construed as limited to the
particular forms disclosed, since these are to be regarded as
illustrative rather than restrictive. Var ations and changes may
be made by those skilled in the art without departing from the
spirit of the invention.
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