CA1078874A - Polyhydroxy phenols and process for their preparation - Google Patents
Polyhydroxy phenols and process for their preparationInfo
- Publication number
- CA1078874A CA1078874A CA263,674A CA263674A CA1078874A CA 1078874 A CA1078874 A CA 1078874A CA 263674 A CA263674 A CA 263674A CA 1078874 A CA1078874 A CA 1078874A
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- CA
- Canada
- Prior art keywords
- phenol
- acid
- para
- reaction
- formaldehyde
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/02—Polycondensates containing more than one epoxy group per molecule
- C08G59/04—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof
- C08G59/06—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof of polyhydric phenols
- C08G59/08—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof of polyhydric phenols from phenol-aldehyde condensates
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C39/00—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring
- C07C39/12—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring polycyclic with no unsaturation outside the aromatic rings
- C07C39/15—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a six-membered aromatic ring polycyclic with no unsaturation outside the aromatic rings with all hydroxy groups on non-condensed rings, e.g. phenylphenol
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
- C08G8/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ
- C08G8/24—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ with mixtures of two or more phenols which are not covered by only one of the groups C08G8/10 - C08G8/20
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Phenolic Resins Or Amino Resins (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Polyhydroxy phenol according to the formula:
where R is an alkyl radical containing from 1 to 10 carbon atoms, the methylene bridges being bonded to the central phenol ring in the ortho- positions in relation to the hydroxyl group and to the other phenol rings in the ortho- or para- positions in relation to the hydroxyl group.
This polyhydroxy phenol can be used as antioxi-dants for plastics materials and stabilizers for unsaturated polyester resins, and for preparing epoxy resins, novolaks and resols.
Polyhydroxy phenol according to the formula:
where R is an alkyl radical containing from 1 to 10 carbon atoms, the methylene bridges being bonded to the central phenol ring in the ortho- positions in relation to the hydroxyl group and to the other phenol rings in the ortho- or para- positions in relation to the hydroxyl group.
This polyhydroxy phenol can be used as antioxi-dants for plastics materials and stabilizers for unsaturated polyester resins, and for preparing epoxy resins, novolaks and resols.
Description
~ 71 : `
This invention relal;es to new polyhydroxy phenols defined by the following formula:
O~ ~ OH
I OH
(I) ~ C~2 - ~ C~I2 R
where R is an alkyl radical contalning from 1 to 10 carbor atoms, the methylene bridge being bonded to the central .
phenol rin~ in the ortho- positions in relati.on to the .: hydroxyl eroup~ and to the other phenol rings in the ortho-~, . .
or para po~ition in relation to the hydro~yl group.
The invention also concerns a method for preparing the said polyhydroxy phenols, by reacting formaldehyde with phenol substituted in the para position with an allcyl group with from 1 to 10 carbon atoms, to give the dimethylol derivative by substitution with two methylol groups in the :
I ortho positlons in relation to the hydroxyl group o~ the said -~ substituted phenol, and the said dimethylol derivative is ' I reacted with phenol to give a polyhydroxy phenol (I).
`I .
-l~ In the followillg de~cription:
~ - by "para-substituted phenol" there is meant phenol sub~
i1 stituted ln the para position in relation to the phenolic ~¦ hydroxy group with an alkyl group having from 1 to 10 carbon ;1 atoms;
.1 .
¦ - by "dimethylol derlvative", or else by "dimethylol inter-mediate" there is meant the para-substituted phenol sub~tituted with two methylol groups in the ortho positions in relation _ _ , ~
1~'78~7~ -~o the hydroxyl ~roup.
- by "polyhydroxy phenol" there is meant a compound according :
to formula (I).
The methodfor preparing the polyhydroxy phenol of this invention comprises the following stages:
(a) reacting formaldehyde and a substituted phenol of the ~.
formula:
HQ ~ R
where R is an alkyl radical containing from 1 to 10 carbon atoms, in a formaldehyde/phenol molar ratio of at least 2:1, in the presence of an inorganic base and at a temperature of at least 40C, thereby to form a dimethylol derivative of said phenol;
~ (b) adding an acid to the reaction products of (a) in an ; amount at least equivalent to that of said inorganic base and . in the presence of water, and separating the aqueous phase and the dimethylol derivative phase thus obtained;
(c) adding to said dimethylol derivative phase an organic :~ solvent capable of dissolving said derivative, normally immiscible or slightly miscible with water and forming with the latter an azeotropic mixture, contacting the resulting solution with phenol in a molar ratio between said phenol and said derivative of at least 2:1, in the presence of an acid catalyst and at a temperature of at least 100C, and maintaining the resulting mixture at boiling point until : substantially complete reaction of said derivative with said ~ phenol, while distilling the iorming wate~ as an a~eotrope ,~
bm:
.
. . ~
~l~7i387~
~ithi ~iaid organic solvc~t; and . (d) recovering the polyhydroxy phenol from tlle reaction . products of ~c).
Stage a . According to the process of this invention forMaldehyde ~ ~ is reacted with a para-substituted phen-ol, the~atter bein~
; preferably chosen from para-tert-butylphenol 9 para-cresol, ; para-octylphenol, para-amylphenol and para~llonylPhenol. The ~: formaldehyde can be fed into the reaction medlum as an aqueous solution, especially in the form of those comme}cial ;; aqueous solutions which have a formaldehyde content of the order of 37-38% by weight. Low polymers of formaldehyde, : such as paraformaldehyde, or anyway, any substance which - frees formaldehyde under the reaction condit:ions can also be used for the purpose.
The reaction is catalyzed by an inorganic base and pre~erably an alkali metal hydroxyde, such as sodium, potassium or lithium hydroxide.
j.~ The molar ratio of the forn~aldehyde to the parasubGitituted.1 .
phenol is generally from 2:1 to 3:1 and that of the inorganic base to the said p~ra-substituted phenol generally from 0.3i1 to 1~
Further~ the reaction is preferably carried out at a ; . .
! .I temperàture of from 40 to 8CiC and for a time such as to :. ensure complete reaction of the para-substituted phenol or . . ~ ~ - .
at least until the concentratlon of the latter is reduced to -~- va~ues below 0.5% by weig~lt in the reaction mediumO The ~ . ' , ~ ' '~ ', ' ' , ,' ,' '' ~ " ' "
~ i ~' ' . ' : ', ' ', ' ' ' ' 887~
reaction time is ~enerally rom 1 to 4 hours, The way of contacting the reagents i~ not critical, but it is preferable to yradually add an aqueous solution of the inorganic base to the reaction medium containing formaldehyde and the para-substituted phenol, and to maintain the reaction mixture at the reaction temperature for a certain length of time at the end of the addition of the inorganic base.
The reaction is generally carried out in the presence of water. Preferably, the reaction mixture should not contain more than 50~ by weight of water.
In the preferred embodiment, the molar ratio of alkali metal hydroxide to para-substituted phenol is maintained at about 0.5:1 and that of formaldehyde to para-substituted phenol at about 2.5:1. Further the reaction : is carried out at a temperature of the order of 60C, aqueous sodium hydroxide being fed gradually into the reaction medium.
Under these conditions, the para-substituted phenol reacts almost completely with the formaldehyde in a period of about
This invention relal;es to new polyhydroxy phenols defined by the following formula:
O~ ~ OH
I OH
(I) ~ C~2 - ~ C~I2 R
where R is an alkyl radical contalning from 1 to 10 carbor atoms, the methylene bridge being bonded to the central .
phenol rin~ in the ortho- positions in relati.on to the .: hydroxyl eroup~ and to the other phenol rings in the ortho-~, . .
or para po~ition in relation to the hydro~yl group.
The invention also concerns a method for preparing the said polyhydroxy phenols, by reacting formaldehyde with phenol substituted in the para position with an allcyl group with from 1 to 10 carbon atoms, to give the dimethylol derivative by substitution with two methylol groups in the :
I ortho positlons in relation to the hydroxyl group o~ the said -~ substituted phenol, and the said dimethylol derivative is ' I reacted with phenol to give a polyhydroxy phenol (I).
`I .
-l~ In the followillg de~cription:
~ - by "para-substituted phenol" there is meant phenol sub~
i1 stituted ln the para position in relation to the phenolic ~¦ hydroxy group with an alkyl group having from 1 to 10 carbon ;1 atoms;
.1 .
¦ - by "dimethylol derlvative", or else by "dimethylol inter-mediate" there is meant the para-substituted phenol sub~tituted with two methylol groups in the ortho positions in relation _ _ , ~
1~'78~7~ -~o the hydroxyl ~roup.
- by "polyhydroxy phenol" there is meant a compound according :
to formula (I).
The methodfor preparing the polyhydroxy phenol of this invention comprises the following stages:
(a) reacting formaldehyde and a substituted phenol of the ~.
formula:
HQ ~ R
where R is an alkyl radical containing from 1 to 10 carbon atoms, in a formaldehyde/phenol molar ratio of at least 2:1, in the presence of an inorganic base and at a temperature of at least 40C, thereby to form a dimethylol derivative of said phenol;
~ (b) adding an acid to the reaction products of (a) in an ; amount at least equivalent to that of said inorganic base and . in the presence of water, and separating the aqueous phase and the dimethylol derivative phase thus obtained;
(c) adding to said dimethylol derivative phase an organic :~ solvent capable of dissolving said derivative, normally immiscible or slightly miscible with water and forming with the latter an azeotropic mixture, contacting the resulting solution with phenol in a molar ratio between said phenol and said derivative of at least 2:1, in the presence of an acid catalyst and at a temperature of at least 100C, and maintaining the resulting mixture at boiling point until : substantially complete reaction of said derivative with said ~ phenol, while distilling the iorming wate~ as an a~eotrope ,~
bm:
.
. . ~
~l~7i387~
~ithi ~iaid organic solvc~t; and . (d) recovering the polyhydroxy phenol from tlle reaction . products of ~c).
Stage a . According to the process of this invention forMaldehyde ~ ~ is reacted with a para-substituted phen-ol, the~atter bein~
; preferably chosen from para-tert-butylphenol 9 para-cresol, ; para-octylphenol, para-amylphenol and para~llonylPhenol. The ~: formaldehyde can be fed into the reaction medlum as an aqueous solution, especially in the form of those comme}cial ;; aqueous solutions which have a formaldehyde content of the order of 37-38% by weight. Low polymers of formaldehyde, : such as paraformaldehyde, or anyway, any substance which - frees formaldehyde under the reaction condit:ions can also be used for the purpose.
The reaction is catalyzed by an inorganic base and pre~erably an alkali metal hydroxyde, such as sodium, potassium or lithium hydroxide.
j.~ The molar ratio of the forn~aldehyde to the parasubGitituted.1 .
phenol is generally from 2:1 to 3:1 and that of the inorganic base to the said p~ra-substituted phenol generally from 0.3i1 to 1~
Further~ the reaction is preferably carried out at a ; . .
! .I temperàture of from 40 to 8CiC and for a time such as to :. ensure complete reaction of the para-substituted phenol or . . ~ ~ - .
at least until the concentratlon of the latter is reduced to -~- va~ues below 0.5% by weig~lt in the reaction mediumO The ~ . ' , ~ ' '~ ', ' ' , ,' ,' '' ~ " ' "
~ i ~' ' . ' : ', ' ', ' ' ' ' 887~
reaction time is ~enerally rom 1 to 4 hours, The way of contacting the reagents i~ not critical, but it is preferable to yradually add an aqueous solution of the inorganic base to the reaction medium containing formaldehyde and the para-substituted phenol, and to maintain the reaction mixture at the reaction temperature for a certain length of time at the end of the addition of the inorganic base.
The reaction is generally carried out in the presence of water. Preferably, the reaction mixture should not contain more than 50~ by weight of water.
In the preferred embodiment, the molar ratio of alkali metal hydroxide to para-substituted phenol is maintained at about 0.5:1 and that of formaldehyde to para-substituted phenol at about 2.5:1. Further the reaction : is carried out at a temperature of the order of 60C, aqueous sodium hydroxide being fed gradually into the reaction medium.
Under these conditions, the para-substituted phenol reacts almost completely with the formaldehyde in a period of about
2.5 hours.
Stage b . .
An acid is added to the reaction products from stage a) in an amount at least equivalent to that of the inorganic base fed in stage a)~
Organic acids may be used for the purpose, but mineral acids, such as, for example, hydrochloric, sulphuric or phosphoric acids are preferable. Among the latter, j phosphoric acid is preferred, for reasons of corrosion.
The amount of acid which is generally added is that required o bring the p~ of the medium to a value of from ~ . .
_5_ bm:
78~
6.5 to 2, Following the treatment with acid, the dimethylol intermediate becomes insoluble in water and it becomes possible to separate it from the aqueous phase containing the unreacted formaldehyde and the neutralization products of the inorganic base. Obviously, if stage (a) is carried out in the absence of added water, water is added in stage (b) of the process.
; In a preferred embodiment the reaction products from the first stage are cooled down to about 50C and phosphoric acid is added gradually up to an equivalent ratio of sodium hydroxide to phosphoric acid of the order of 0.5:1 The mixture is then decanted at 40-50C with separation of the aqueous layer (which is discharged) from the organic layer consisting essentially of the dimethylol intermediateO
Stage c ~
To the dimethylol intermediate recovered in stage b) there is added an organic solvent capable of dissolving the said intermediate, normally immiscible or only slightly miscible with water and forming an azeotropic mixture with the latter.
Particularly useful for this purpose are aromatic hydrocarbons such as toluene, xylene, cumene or other alkyl benzenes, boiling at a temperature not exceeding 160C.
To the solution thus obtained phenol is generally added in such amount as to ensure a molar ratio of the para-substituted phenol (fed in in stage a) to the phenol, of from 1:2 to 1:3.5.
The reaction is carried out at boiling point, generally at a temperature of from 100 to 160C, the water ' ' ; ~m:
.- . .
, '. .
.- . .~ : , . . . ' , : . .
:.~ ... . . . ,: , . :
iL~37~387g~
which forms being dis~illed continuously in the form of an azeotrope with the pr~selected organic solvent, The reaction of the dimethylol intermediate with phenol is carried out in the presence of an acid catalyst, preferably an organic acid The said acid should preferably have an acid dissociation constan~, or else (in the case of a polybasic acid) a first acid dissociation constant which is greater than 1.10 '. Examples of organic acids suitable for the purpose are: oxalic acid, benzoic acid, para-tert-butylbenzoic acid, salicylic acid and isophthalic acid, The amount of acid catalyst is generally from 0.1 to 5 parts by weight for every 100 parts by weight of phenol.
Reaction times are those necessary for practically complete reaction of the dimethylol derivative and are generally from 2 to 4 hours In a preferred embodiment, the solution of the dimethylol intermediate in the preselected solvent is added to the phenol and the catalyst, the reaction mixture being maintained at boiling point. The vapours which are e~olved are condensed, with separation of an aqueous phase which is discharged, and of an organic phase, which is recycled into the reaction medium.
- Stage d The acid catalyst, the organic solvent, and any excess phenol are removed from the reaction products derived from stage (c).
In the case of the use of oxalic acid, the said acid is insoluble in the reaction medium at temperatures of the order of 30-40C. It can therefore be precipitated '~ .
:: ' bm:
,:
:,'' ' ' . ....
7~ 79~
by cooling the xe~c~ion m~ss and can then be filt~red, In other cases it may be necessary to neutralize the acid catalyst and filtex the precipita~ed salt.
The organic solvent and the excess phenol may be removed, the former by means of distillation at atmospheric or near atmospheric pressure, the second at a pressure lower than atmospheric, preferably by means of the thin film method. Obviously the said organic solvent and phenol can be re-used in the process for preparation of the polyhydroxy phenol. This latter remains in every case as a distillation residue~
By the process described the polyhydroxy phenol is obtained in its isomeric forms, which can be used as such for the purposes for which the polyhydroxy phenols are normally employed. Obviously, if wished, the various isomers can be separated by means of the usual methods, such as, for ` example, fractional crystallization.
The polyhydroxy phenols of this invention are especially useful as antioxidants for elastomers and plastics materials, as polymerization inhibitors for unsaturated monomers such as styrene and the alkyl esters of acrylic or methacrylic acid and as stabilizers for unsaturated polyester resins tproducts of the polycondensation of unsaturated polybasic acids and polyhydroxy alcohols, dissolved in styrene or another unsaturated monomer).
The polyhydroxy phenols of the invention are also ~--useful for preparing epoxy resins by reaction with epichloro-hydrin in an alkaline medium and the said epoxy resins are particularly ~uitable for paints with improved thermal and dimensional resistance, and resistance to chemical reagents.
" .
Novolak phenolic resins with higher molecular weight I bm: ~
.: ' ' . ; ..
. , .
~.~7~3~37~ :
than the conventional ones can be prepared by reacting the polyhydroxy phcnols ~I) in an acid mediwn with formaldehyde, possibly in the presence o phenol or phenolic compounds i general.
Resol phenolic resins can also be prepared in basic medium by reacting the same reagents in different ratios.
; The said Novolaks are particularly useful when -employed in combination with hexamine, as binders for mineral charges (for example sand for moulds or abrasives) or vegetable fillings, such as wood flour, or else as reinforcers or adhesives for ruhber.
The said resols are particularly useful for impregnating paper and fabrics, for making laminates, or else, suitably modified with vegetable oils, they can be used for hard and chemically resistant glossy stove enamels.
In the following experimental example the parts and percentages are by weight unless otherwise specified, ~ . ;
Into a reactor furnished with an agitator, a steam heating system, a hypsometer, a reservoir for feeding in the reagents, a condensor, a demixer, a reflux duct for the condensate and collecting chamber for the distillate, there are fed in 426:7 parts of para-tert-butylphenol and 604 parts of a 36% aqueous solution of formaldehyde. The molar ratio of formaldehyde to para-tert-butylphenol is thus equal to 2.5:1.
; The temperature is taken to 60C and 190 parts of a 30~ aqueous solution of sodium hydroxide are added gradually to the agitated mass.
At the end of the addition of the latter the molar ~ .
; :"
_9_ ~m--: , : , ~ - ' .
78l~7~
ratio of para-tert-butylphenol to sodium hydroxide is equal to 2:1. A~ter this acldition the temperature is maintained at 60C until the amount o~ free formaldehyde in the reaction medium is reduced to 4-4.5%.
119 parts of a 75~ aqueous solution of phosphoric acid are then added. Agitation is maintained until neutralization is complete, The agitator is then stopped and an aqueous phase containing unreacted ~ormaldehyde and sodium phosphates, and an organic phase containing the dimethylol derivative of p-tert-butylphenol are separated.
The aqueous phase is discharged, and 360 parts of toluene are added to the organic phase ~720 parts), thus obtaining a toluene solution which has the following characteristics:
dry matter: 52%
viscosity at 25C in cps: 25 free para-tert-butylphenol: absent This last determination was carried out by means of gas-chromatographic analysis.
A mixture of 737 parts of phenol and 32 parts of oxalic acid, is heated to 100C and the toluene solution of the dimethylol intermediate is added gradually to the heated mixture over a period of three hours. During this period of time the mass is kept boiling and the water is azeotropically distilled and is continuously removed through a demixer.
The distilled toluene is recycled into the reaction medium.
The temperature of the mass rises rapidly to 120-125C during the addition of the toluene solution and remains at these values until the end of the said addition, -~' '' .
bm:
. ' . ., .. : , : ~ :
~ ~78~. 7~
~he molar ratio of the phenol to the para-t~l~t~bu~ylphenol ~fad in initially) in the reaction mediwn being then of 2,7:1.
After the addition of the toluene solution the said temperature is maintained for 30 minutes and the mass is then cooled to 30-40Co At this temperature the oxalic acid, dispersed in the solution, is removed by filtering.
- The resulting solution has the following characteristics:
dry matter: 64%
viscosity at 40C in cps: 900 free phenol: 16%
Thls latter determination was carried out by means of gas-chromatography.
The solution is subjected to distillation at atmospheric pressure and 253 parts of toluene containing ' small amounts of phenol are distilled off.
The residue is distilled by the thin film method at a pressure of 3 mm Hg to remove the residual toluene and the unreacted phenol.
At the base of the evaporator about 1000 parts by weight of a polyhydroxy phenol having the following characteristics are recovered:
, - appearance : solid - melting point (in capillary): 74C
~, - viscosity at 25C in 50% ethanol solution: 33 cps , - pEI in 50~ ethanol solution: 4 - Gardner melting colour: 6 ~ 30 - free phenol (gas-chromatography). < 0,5%
i/' - free para-tert-butylphenol (gas-chromatography): absent ;' ;
bm:
.
.
-1~7~387~
The product iS solubl~ in mos~ of the organic solvents.
~ nalysis o~ the NMR spectra gives the following results:
- Mn(OM) = average numerical molecular weight: 364 - n -- average number of hydroxyl groups per molecule: 3,0 - RA = average number of aromatic protons per ring~ 3,0 ~ RM~ = average number of methylene bridges per benzene ring:
0.6 - 10 - isomers : ortho~ortho' ~ 5%
ortho-para : 95%
- para-tert-butylphenol/phenol molar ratio: 1:2 :~
The product is therefore the polyhydroxy phenol of formula (I) in its two isomeric forms.
, ,:
"~ .
'': ' ' bm:
,: ', , - , . , . ' ; , !
~, : , '- :, , , ' ' , , ' :.' ' . '
Stage b . .
An acid is added to the reaction products from stage a) in an amount at least equivalent to that of the inorganic base fed in stage a)~
Organic acids may be used for the purpose, but mineral acids, such as, for example, hydrochloric, sulphuric or phosphoric acids are preferable. Among the latter, j phosphoric acid is preferred, for reasons of corrosion.
The amount of acid which is generally added is that required o bring the p~ of the medium to a value of from ~ . .
_5_ bm:
78~
6.5 to 2, Following the treatment with acid, the dimethylol intermediate becomes insoluble in water and it becomes possible to separate it from the aqueous phase containing the unreacted formaldehyde and the neutralization products of the inorganic base. Obviously, if stage (a) is carried out in the absence of added water, water is added in stage (b) of the process.
; In a preferred embodiment the reaction products from the first stage are cooled down to about 50C and phosphoric acid is added gradually up to an equivalent ratio of sodium hydroxide to phosphoric acid of the order of 0.5:1 The mixture is then decanted at 40-50C with separation of the aqueous layer (which is discharged) from the organic layer consisting essentially of the dimethylol intermediateO
Stage c ~
To the dimethylol intermediate recovered in stage b) there is added an organic solvent capable of dissolving the said intermediate, normally immiscible or only slightly miscible with water and forming an azeotropic mixture with the latter.
Particularly useful for this purpose are aromatic hydrocarbons such as toluene, xylene, cumene or other alkyl benzenes, boiling at a temperature not exceeding 160C.
To the solution thus obtained phenol is generally added in such amount as to ensure a molar ratio of the para-substituted phenol (fed in in stage a) to the phenol, of from 1:2 to 1:3.5.
The reaction is carried out at boiling point, generally at a temperature of from 100 to 160C, the water ' ' ; ~m:
.- . .
, '. .
.- . .~ : , . . . ' , : . .
:.~ ... . . . ,: , . :
iL~37~387g~
which forms being dis~illed continuously in the form of an azeotrope with the pr~selected organic solvent, The reaction of the dimethylol intermediate with phenol is carried out in the presence of an acid catalyst, preferably an organic acid The said acid should preferably have an acid dissociation constan~, or else (in the case of a polybasic acid) a first acid dissociation constant which is greater than 1.10 '. Examples of organic acids suitable for the purpose are: oxalic acid, benzoic acid, para-tert-butylbenzoic acid, salicylic acid and isophthalic acid, The amount of acid catalyst is generally from 0.1 to 5 parts by weight for every 100 parts by weight of phenol.
Reaction times are those necessary for practically complete reaction of the dimethylol derivative and are generally from 2 to 4 hours In a preferred embodiment, the solution of the dimethylol intermediate in the preselected solvent is added to the phenol and the catalyst, the reaction mixture being maintained at boiling point. The vapours which are e~olved are condensed, with separation of an aqueous phase which is discharged, and of an organic phase, which is recycled into the reaction medium.
- Stage d The acid catalyst, the organic solvent, and any excess phenol are removed from the reaction products derived from stage (c).
In the case of the use of oxalic acid, the said acid is insoluble in the reaction medium at temperatures of the order of 30-40C. It can therefore be precipitated '~ .
:: ' bm:
,:
:,'' ' ' . ....
7~ 79~
by cooling the xe~c~ion m~ss and can then be filt~red, In other cases it may be necessary to neutralize the acid catalyst and filtex the precipita~ed salt.
The organic solvent and the excess phenol may be removed, the former by means of distillation at atmospheric or near atmospheric pressure, the second at a pressure lower than atmospheric, preferably by means of the thin film method. Obviously the said organic solvent and phenol can be re-used in the process for preparation of the polyhydroxy phenol. This latter remains in every case as a distillation residue~
By the process described the polyhydroxy phenol is obtained in its isomeric forms, which can be used as such for the purposes for which the polyhydroxy phenols are normally employed. Obviously, if wished, the various isomers can be separated by means of the usual methods, such as, for ` example, fractional crystallization.
The polyhydroxy phenols of this invention are especially useful as antioxidants for elastomers and plastics materials, as polymerization inhibitors for unsaturated monomers such as styrene and the alkyl esters of acrylic or methacrylic acid and as stabilizers for unsaturated polyester resins tproducts of the polycondensation of unsaturated polybasic acids and polyhydroxy alcohols, dissolved in styrene or another unsaturated monomer).
The polyhydroxy phenols of the invention are also ~--useful for preparing epoxy resins by reaction with epichloro-hydrin in an alkaline medium and the said epoxy resins are particularly ~uitable for paints with improved thermal and dimensional resistance, and resistance to chemical reagents.
" .
Novolak phenolic resins with higher molecular weight I bm: ~
.: ' ' . ; ..
. , .
~.~7~3~37~ :
than the conventional ones can be prepared by reacting the polyhydroxy phcnols ~I) in an acid mediwn with formaldehyde, possibly in the presence o phenol or phenolic compounds i general.
Resol phenolic resins can also be prepared in basic medium by reacting the same reagents in different ratios.
; The said Novolaks are particularly useful when -employed in combination with hexamine, as binders for mineral charges (for example sand for moulds or abrasives) or vegetable fillings, such as wood flour, or else as reinforcers or adhesives for ruhber.
The said resols are particularly useful for impregnating paper and fabrics, for making laminates, or else, suitably modified with vegetable oils, they can be used for hard and chemically resistant glossy stove enamels.
In the following experimental example the parts and percentages are by weight unless otherwise specified, ~ . ;
Into a reactor furnished with an agitator, a steam heating system, a hypsometer, a reservoir for feeding in the reagents, a condensor, a demixer, a reflux duct for the condensate and collecting chamber for the distillate, there are fed in 426:7 parts of para-tert-butylphenol and 604 parts of a 36% aqueous solution of formaldehyde. The molar ratio of formaldehyde to para-tert-butylphenol is thus equal to 2.5:1.
; The temperature is taken to 60C and 190 parts of a 30~ aqueous solution of sodium hydroxide are added gradually to the agitated mass.
At the end of the addition of the latter the molar ~ .
; :"
_9_ ~m--: , : , ~ - ' .
78l~7~
ratio of para-tert-butylphenol to sodium hydroxide is equal to 2:1. A~ter this acldition the temperature is maintained at 60C until the amount o~ free formaldehyde in the reaction medium is reduced to 4-4.5%.
119 parts of a 75~ aqueous solution of phosphoric acid are then added. Agitation is maintained until neutralization is complete, The agitator is then stopped and an aqueous phase containing unreacted ~ormaldehyde and sodium phosphates, and an organic phase containing the dimethylol derivative of p-tert-butylphenol are separated.
The aqueous phase is discharged, and 360 parts of toluene are added to the organic phase ~720 parts), thus obtaining a toluene solution which has the following characteristics:
dry matter: 52%
viscosity at 25C in cps: 25 free para-tert-butylphenol: absent This last determination was carried out by means of gas-chromatographic analysis.
A mixture of 737 parts of phenol and 32 parts of oxalic acid, is heated to 100C and the toluene solution of the dimethylol intermediate is added gradually to the heated mixture over a period of three hours. During this period of time the mass is kept boiling and the water is azeotropically distilled and is continuously removed through a demixer.
The distilled toluene is recycled into the reaction medium.
The temperature of the mass rises rapidly to 120-125C during the addition of the toluene solution and remains at these values until the end of the said addition, -~' '' .
bm:
. ' . ., .. : , : ~ :
~ ~78~. 7~
~he molar ratio of the phenol to the para-t~l~t~bu~ylphenol ~fad in initially) in the reaction mediwn being then of 2,7:1.
After the addition of the toluene solution the said temperature is maintained for 30 minutes and the mass is then cooled to 30-40Co At this temperature the oxalic acid, dispersed in the solution, is removed by filtering.
- The resulting solution has the following characteristics:
dry matter: 64%
viscosity at 40C in cps: 900 free phenol: 16%
Thls latter determination was carried out by means of gas-chromatography.
The solution is subjected to distillation at atmospheric pressure and 253 parts of toluene containing ' small amounts of phenol are distilled off.
The residue is distilled by the thin film method at a pressure of 3 mm Hg to remove the residual toluene and the unreacted phenol.
At the base of the evaporator about 1000 parts by weight of a polyhydroxy phenol having the following characteristics are recovered:
, - appearance : solid - melting point (in capillary): 74C
~, - viscosity at 25C in 50% ethanol solution: 33 cps , - pEI in 50~ ethanol solution: 4 - Gardner melting colour: 6 ~ 30 - free phenol (gas-chromatography). < 0,5%
i/' - free para-tert-butylphenol (gas-chromatography): absent ;' ;
bm:
.
.
-1~7~387~
The product iS solubl~ in mos~ of the organic solvents.
~ nalysis o~ the NMR spectra gives the following results:
- Mn(OM) = average numerical molecular weight: 364 - n -- average number of hydroxyl groups per molecule: 3,0 - RA = average number of aromatic protons per ring~ 3,0 ~ RM~ = average number of methylene bridges per benzene ring:
0.6 - 10 - isomers : ortho~ortho' ~ 5%
ortho-para : 95%
- para-tert-butylphenol/phenol molar ratio: 1:2 :~
The product is therefore the polyhydroxy phenol of formula (I) in its two isomeric forms.
, ,:
"~ .
'': ' ' bm:
,: ', , - , . , . ' ; , !
~, : , '- :, , , ' ' , , ' :.' ' . '
Claims (21)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polyhydroxy phenol defined by the formula;
where R is an alkyl radical containing from 1 to 10 carbon atoms, the methylene bridges being bonded to the central phenol ring in the ortho- positions in relation to the hydroxyl group, and to the other phenol rings in the ortho-or para- position in relation to the hydroxyl group.
where R is an alkyl radical containing from 1 to 10 carbon atoms, the methylene bridges being bonded to the central phenol ring in the ortho- positions in relation to the hydroxyl group, and to the other phenol rings in the ortho-or para- position in relation to the hydroxyl group.
2. A process for preparing the polyhydroxy phenol of claim 1, which comprises:
(a) reacting formaldehyde and a substituted phenol of the formula:
where R is an alkyl radical containing from 1 to 10 carbon atoms, in a formaldehyde/phenol molar ratio of at least 2:1 in the presence of an inorganic base and at a temperature of at least 40°C, thereby to form a dimethylol derivative of said phenol;
(b) adding an acid to the reaction products of (a) in an amount at least equivalent to that of said inorganic base and in the presence of water, and separating the aqueous phase and the dimethylol derivative phase thus obtained;
(c) adding to said dimethylol derivative phase an organic solvent capable of dissolving said derivative, normally immiscible or slightly miscible with water and forming with the latter an azeotropic mixture, contacting the resulting solution with phenol in a molar ratio between said phenol and said derivative of at least 2:1, in the presence of an acid catalyst and at a temperature of at least 100°C, and maintaining the resulting mixture at boiling point until substantially complete reaction of said derivative with said phenol, while distilling the forming water as an azeotrope with said organic solvent; and (d) recovering the polyhydroxy phenol from the reaction products of (c).
(a) reacting formaldehyde and a substituted phenol of the formula:
where R is an alkyl radical containing from 1 to 10 carbon atoms, in a formaldehyde/phenol molar ratio of at least 2:1 in the presence of an inorganic base and at a temperature of at least 40°C, thereby to form a dimethylol derivative of said phenol;
(b) adding an acid to the reaction products of (a) in an amount at least equivalent to that of said inorganic base and in the presence of water, and separating the aqueous phase and the dimethylol derivative phase thus obtained;
(c) adding to said dimethylol derivative phase an organic solvent capable of dissolving said derivative, normally immiscible or slightly miscible with water and forming with the latter an azeotropic mixture, contacting the resulting solution with phenol in a molar ratio between said phenol and said derivative of at least 2:1, in the presence of an acid catalyst and at a temperature of at least 100°C, and maintaining the resulting mixture at boiling point until substantially complete reaction of said derivative with said phenol, while distilling the forming water as an azeotrope with said organic solvent; and (d) recovering the polyhydroxy phenol from the reaction products of (c).
3. The process of claim 2, wherein said substituted phenol is selected from the group consisting of para-tert-butylphenol, para-cresol, para-octylphenol, para-amylphenol and para-nonylphenol.
4. The process of claim 2, wherein said formaldehyde is fed into the reaction medium of (a) in the form of an aqueous solution or a substance which frees formaldehyde under the reaction conditions.
5. The process of claim 2, wherein said formaldehyde/
phenol molar ratio is from 2:1 to 3:1.
phenol molar ratio is from 2:1 to 3:1.
6. The process of claim 2, wherein said inorganic base is an alkali metal hydroxide, the molar ratio between said inorganic base and said substituted phenol being from 0.3:1 to 1:1.
7. The process of claim 2, wherein stage (a) is carried out at a temperature of from 40 to 80°C.
8. The process of claim 2, wherein stage (a) is carried out for a period of from 1 to 4 hours.
9. The process of claim 2, wherein the reaction mixture of (a) does not contain more than 50% by weight of water.
10. The process of claim 2, wherein said acid of (b) is an inorganic acid.
11. The process of claim 29 wherein said acid of (b) is selected from the group consisting of hydrochloric, sulphuric and phosphoric acids.
12. The process of claim 2, wherein said acid of (b) is added in an amount such as to bring the pH to a value of from 2 to 6.5.
13. The process of claim 2, wherein said organic solvent is an aromatic hydrocarbon having a boiling point not exceeding 160°C.
14. The process of claim 2, wherein said phenol of (c) is used in an amount of from 2 to 3.5 moles for each mole of substituted phenol used in (a).
15. The process of claim 2, wherein said mixture of (c) is boiled a t a temperature of from 100 to 160°C.
16. The process of claim 2, wherein said acid catalyst is an organic acid.
17. The process of claim 2, wherein said acid catalyst is an acid having an acid dissociation constant, or else (in the case of a polybasic acid) a first acid dissociation constant above 1.10-5.
18. The process of claim 2, wherein said acid catalyst is selected from the group consisting of oxalic, benzoic, para-tert-butylbenzoic, salicylic and isophthalic acids.
19. The process of claim 2, wherein said acid catalyst is used in an amount of from 0.1 to 5 parts by weight for each 100 parts of phenol.
20. The process of claim 2, wherein state (c) is carried out for a period of from 2 to 4 hours.
' ' I
' ' I
21. The process of claim 2, wherein said polyhydroxy phenol is recovered by precipitating the acid catalyst and removing the resulting precipitate, and distilling off the organic solvent and the unreacted phenol present in said reaction products of (c).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT2880975A IT1043743B (en) | 1975-10-30 | 1975-10-30 | POLYUSSIORILIC PHENOLS AND PROCEDURE FOR THEIR PREPARATION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078874A true CA1078874A (en) | 1980-06-03 |
Family
ID=11224223
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA263,674A Expired CA1078874A (en) | 1975-10-30 | 1976-10-19 | Polyhydroxy phenols and process for their preparation |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5257153A (en) |
| CA (1) | CA1078874A (en) |
| DE (1) | DE2648051A1 (en) |
| FR (1) | FR2329631A1 (en) |
| GB (1) | GB1493760A (en) |
| IT (1) | IT1043743B (en) |
| NL (1) | NL7612021A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4173541A (en) | 1978-06-05 | 1979-11-06 | Cincinnati Milacron Chemicals Inc. | Polynuclear hindered phenols and stabilized organic materials containing the phenols |
| JPS62119220A (en) * | 1985-11-18 | 1987-05-30 | Arakawa Chem Ind Co Ltd | Production of polyhydroxyl compound |
| US20070099130A1 (en) * | 2003-06-25 | 2007-05-03 | Hideaki Takahashi | Developer for recording materials |
| JP2005232038A (en) * | 2004-02-17 | 2005-09-02 | Sumitomo Bakelite Co Ltd | Phenol compound and method for producing the same |
| WO2006075604A1 (en) * | 2005-01-11 | 2006-07-20 | Oji Paper Co., Ltd. | Thermosensitive recording material |
| MX2016014349A (en) * | 2014-05-12 | 2017-04-10 | Si Group Inc | Modified phenolic resins and methods of making and using the same as reinforcing resins. |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2744882A (en) * | 1949-01-26 | 1956-05-08 | Union Carbide & Carbon Corp | Unsymmetrical diphenylol methanes |
| DE915341C (en) * | 1950-09-06 | 1954-07-19 | Union Carbide & Carbon Corp | Process for the preparation of triphenylene compounds |
| US2841627A (en) * | 1952-10-10 | 1958-07-01 | Monsanto Chemicals | Method of preserving a rubber with an alpha, alpha'-bis(hydroxyphenyl)-2, 6-xylenol ad resulting compositions |
| US2773907A (en) * | 1954-02-05 | 1956-12-11 | American Cyanamid Co | Tris-phenols |
| GB928169A (en) * | 1960-12-02 | 1963-06-06 | Distillers Co Yeast Ltd | Trinuclear phenol antioxidants |
-
1975
- 1975-10-30 IT IT2880975A patent/IT1043743B/en active
-
1976
- 1976-10-12 GB GB4239176A patent/GB1493760A/en not_active Expired
- 1976-10-19 CA CA263,674A patent/CA1078874A/en not_active Expired
- 1976-10-23 DE DE19762648051 patent/DE2648051A1/en not_active Ceased
- 1976-10-29 NL NL7612021A patent/NL7612021A/en not_active Application Discontinuation
- 1976-10-29 JP JP13040876A patent/JPS5257153A/en active Pending
- 1976-10-29 FR FR7632819A patent/FR2329631A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| NL7612021A (en) | 1977-05-03 |
| GB1493760A (en) | 1977-11-30 |
| IT1043743B (en) | 1980-02-29 |
| FR2329631A1 (en) | 1977-05-27 |
| JPS5257153A (en) | 1977-05-11 |
| FR2329631B1 (en) | 1981-12-04 |
| DE2648051A1 (en) | 1977-05-18 |
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