CA2022214A1 - Preparation of cyanate esters - Google Patents
Preparation of cyanate estersInfo
- Publication number
- CA2022214A1 CA2022214A1 CA002022214A CA2022214A CA2022214A1 CA 2022214 A1 CA2022214 A1 CA 2022214A1 CA 002022214 A CA002022214 A CA 002022214A CA 2022214 A CA2022214 A CA 2022214A CA 2022214 A1 CA2022214 A1 CA 2022214A1
- Authority
- CA
- Canada
- Prior art keywords
- amine
- phenolic compound
- bis
- base
- hydroxy
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C261/00—Derivatives of cyanic acid
- C07C261/02—Cyanates
Abstract
A B S T R A C T
PREPARATION OF CYANATE ESTERS
A process for preparing a cyanate ester comprising the steps of:
(a) reacting a phenolic compound with a base to produce a salt of said phenolic compound and said base; and (b) reacting said salt with a cyanogen halide, and recovering a cyanate ester from the reaction mixture.
PREPARATION OF CYANATE ESTERS
A process for preparing a cyanate ester comprising the steps of:
(a) reacting a phenolic compound with a base to produce a salt of said phenolic compound and said base; and (b) reacting said salt with a cyanogen halide, and recovering a cyanate ester from the reaction mixture.
Description
2~222 ~
PREPARATION OF CYANATE ESTERS
This invention relates to the preparation of cyanate esters.
In one aspect, the invention relates to a high-~emperature method for preparation of cyanate esters.
Cyanate esters are thermosettable materials of interest in electronics applicstions because of their ease of processabillty, low dielectric constants and high glass transition temperatures.
One drawback of cyanate esters, however, is that their preparation, which involves the base-catalyzed reaction of a cyanogen halide and a phenolic resin, requires such low temperatures, ~enerally in the ran~e of about -10 to 10C, as to re~uire refrigeration of the reaction mixture. At higher reaction temperatures, the ryanogen halide appears to react with the basic catalyst, competing with the desired reaction of cyano~en halide with the phenolate salt and lowering the yield of cyanate ester product. It would be desirable, for practical as well as economic reasons, to prepare cyanate esters in good yields at a higher temperature.
It is therefore an object of the invention to provide a relatively high-temperature process for the preparation of cyanate esters.
According to the invention, cyanate esters are prepared in a process comprising the steps of:
~a) reactlng a phenolic compound with a base to produre a salt of said phenolic compound and sald base; and (b) reacting said salt with a cyanogen halide, and recovering a cyanate ester from the reaction mixture.
The phenolic react~nt can be any aromatic compound containing one or more reactive hydroxyl groups. The phenolic reactant is preferably a di- or polyhydroxy compound of the formula (OH)a - (OH)a ~OH)a - A ~ - A
n 2~222~4 in which each a and b is independently 0, 1, 2 or 3 and at least one a is not 0, the sum of a + b equallin~ at ~ost 5 in each of the terminal phenyl groups and equalling at mos~ 4 in each of the internal phenylene groups; n is from 0 to 8, preferably 0 to 3;
each R is independently selected from hydro~en, Cl 6 alkyl, Cl 6 allyl, halogen, Cl 6 alkoxy, msleimide, propargyl ether, glycidyl ether or phenyl; and A is a polyvalen~ linking moiety which is preferably selected from aromatic, nliphatic, cycloaliphatic, polycyclic, and heteroatomic groups. Most preferred examples of linking moiety A include -0-, -S02-, -C0-, -OCO0-, -S-, -Cl 12-' dicyclopentadienyl, aralkyl, aryl, cycloallphatic and a direct bond.
Such phenolic reactants include, for example, phenol, m-, p-dihydroxy benzene, 2-tert-butyl hydroquinone, 2,4-dimethyl resorcinol, 2,5-di-tert-butyl hydroquinone, tetramethyl hydro-quinone, 2,4,6-trimethyl resorcinol, 2,6-di-tert-butyl hydro-quinone, 4-chlororesorcinol; dihydroxy naphthPlenes such as, for example, 2,4-, 1,5-, 1,6-, 1,7-, 2,6- and 2,7-dihydroxy naphthalene; dihydroxy diphenyls such as for example 4,4'-dihydroxy diphenyl, 2,2'-dihydroxy dlphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxy diphenyl, 3,3',5,5'-tetrachloro-4,4'-dihydroxy diphenyl, 3,3', 5,5'-tetrachloro-2,2'-dihydroxy diphenyl, 2,2',6,6'-tetra-chloro-4,4'-dihydroxy diphenyl, 4,4'-bis-[(3-hydroxy)-phenoxy]-diphenyl, 4,4'-bis-[(4-hydroxy)-phenoxy]-diphenyl; 2,2'-dihydroxy-1,1'-binaphthyl; dihydroxy diphenyl ethers such as, for example, 4,4'-dihydroxy diphenyl ether, 3,3', 5,5'-tetramethyl-4,4'-dihydoxy diphenyl ethPr, 3,3',5,5' tetrachloro-4,4'-dihydroxy diphenyl ether, 4,4'-bis-[4-hydroxy phenoxy]-diphenyl ether, 4,4'-bis-[4-hydroxyphenyl isopropyl]-diphenyl ether, 4,4'-bis-[4-hydroxyphenoxy]-benzene, 4,4'-bis-[3-hydroxy phenoxy]-diphenyl ether, 4,4'-bis-[4-(4-hydroxy phenoxy)-phenylsulphone]-diphenyl ether; diphenyl sulphones such as, ~or exa~ple, 4,4'-dihydroxy diphenyl ~ulphone 3,3',5,5' tetra-methyl-4,4'-dihydroxy diphenyl sulphone, 3,3',5,5'-tetrachloro-4,4'-dihydroxy diphenyl sulphone, 4,4'-bis-[4-hydroxy phenyl isopropyl]-diphenyl sulphone, 4,4'-bis-[(4-hydroxy)-phenoxy]-diphenyl sulphone, 4,4'-bis-[(3-hydroxy)-phenoxy]-diphenyl sulphone, 4,4'-bis-[4(4-hydroxy phenyl isopropyl)-phenoxy]-diphenyl sulphone, 4,4'-bis-[4-(4-hydroxy phenyl sulphone)-phenoxy]-diphenyl sulphone, 4,4'-bis-[4-(4-hydroxy)-diphenoxy]-diphenyl sulphone;
dihydroxy diphenyl alkanes such as, for example, 4,4'-dihydroxy diphenyl methane, 4,4'-bis-[4-hydroxy phenyl]-diphenyl methane, 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as BPA), 2,2-bis-(3,5-dimethyl-4-hydroxy phenyl)-propane, 2,2-bis-(3,5-dichloro-4-hydroxy phenyl)-propane, 1,1-bis-l4-hydroxy phenyl]-10cyclohexane, bis-[2-hydroxy-1-naphthyl]-methane, 1,2-bis-[4-hydroxy phenyl]-1,1,2,2-tetramethyl ethane, 4,4'-dihydroxy benzophenone, 4,4'-bis-(4-hydroxy)-phenoxy ben~ophenone, 1,4-bis-[4-hydroxy phenyl isopropyl]-benzene, phloroglucinol and 2,2', 5,5'-tetra-hydroxy diphenyl sulphone.
15Other preferred phenolic reactants are phenolic novolacs, such as BPA novolac and o-cresol novolac. The phenolic novolac may contain substituents as described above, including glycidyl ether, propargyl ether and Cl 6 alkyl groups.
The base employed in the first reaction step can be, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide; an alkali metal alkylate such as sodium methylate or potassium methylate; and various amines.
The preferred base is selected from tertiary amines. Tertiary amines can be represented by the formula R"
I
R' -N -Rn' in which R', R" and R"' represent Cl 36~ preferably Cl 10 alkyl;
aryl such as phenyl; and C4 7 cycloalkyl. ~xamples of cuch tertiary amines include trimethyl amine, triethyl amine, methyl diethyl amine, tripropyl amine, ~ributyl amine, methyl dibutyl amine, dinonyl methyl amine, dimethyl stearyl amine, dimethyl cyclohexyl amine and diethyl aniline. The most preferred tertiary amine is triethylamine.
20222~
In general, although the quantity can vary widely depending on reaction conditions, the base is employed in a quantity of at least 0.7 equivalent, preferably from 0.9 to l.5 equivalents, per hydroxyl ~,roups in the phenolic compound.
The first reaction step will generally be carried out in an organic solvent, including ketones such ~s methyl ethyl ketone, acetone and methyl isobutyl ketone; aliphatic alcohols such as methanol, ethanol, propanol and butanol; amides such as dimethyl formamide and dimethyl acetamide; cyclic ethers such as dLoxane and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene or xylene and mixtures of such or~anic solvents. Water may also be used as a medium for the pre-reaction.
The reaction temperature in the first step can vary depending upon the other reaction conditions, but will generally be carried out at a temperature greater than 30C, preferably within the range of 40 to 80C. Pressure will most conveniently be atmospheric.
The time for completion of the reaction will vary depending upon the other reaction conditions, but will generally be within the range of l to 3 hours.
The second reaction step will be carried out by reacting the salt formed in the first step with a cyanogen halide. The pre-ferred cyanogen halides, because of their a~ailability, are cyanogen chloride and cyanogen bromide. The reaction is preferably carried out in a solvent, such as those described above for the pre-reaction, under an inert atmosphere such as nitrogen gas. The reaction temperature can vary within the range of -20C to the boiling temperature of the reactants, but wlll most conveniently be carried out at a temperature above 20C, preferably within the range of 20 to 60C, most preferably 20 to 45C.
The product cyanate ester is recovered from the reaction mixeure by conventional methods such as filtration, centrifugation, distillation, precipitation or solvent extraction, followed by washing.
In a specific embodiment of the invention process, mixed-functionality aromatic compounds having at least one cyanate ester 20222~ '~
PREPARATION OF CYANATE ESTERS
This invention relates to the preparation of cyanate esters.
In one aspect, the invention relates to a high-~emperature method for preparation of cyanate esters.
Cyanate esters are thermosettable materials of interest in electronics applicstions because of their ease of processabillty, low dielectric constants and high glass transition temperatures.
One drawback of cyanate esters, however, is that their preparation, which involves the base-catalyzed reaction of a cyanogen halide and a phenolic resin, requires such low temperatures, ~enerally in the ran~e of about -10 to 10C, as to re~uire refrigeration of the reaction mixture. At higher reaction temperatures, the ryanogen halide appears to react with the basic catalyst, competing with the desired reaction of cyano~en halide with the phenolate salt and lowering the yield of cyanate ester product. It would be desirable, for practical as well as economic reasons, to prepare cyanate esters in good yields at a higher temperature.
It is therefore an object of the invention to provide a relatively high-temperature process for the preparation of cyanate esters.
According to the invention, cyanate esters are prepared in a process comprising the steps of:
~a) reactlng a phenolic compound with a base to produre a salt of said phenolic compound and sald base; and (b) reacting said salt with a cyanogen halide, and recovering a cyanate ester from the reaction mixture.
The phenolic react~nt can be any aromatic compound containing one or more reactive hydroxyl groups. The phenolic reactant is preferably a di- or polyhydroxy compound of the formula (OH)a - (OH)a ~OH)a - A ~ - A
n 2~222~4 in which each a and b is independently 0, 1, 2 or 3 and at least one a is not 0, the sum of a + b equallin~ at ~ost 5 in each of the terminal phenyl groups and equalling at mos~ 4 in each of the internal phenylene groups; n is from 0 to 8, preferably 0 to 3;
each R is independently selected from hydro~en, Cl 6 alkyl, Cl 6 allyl, halogen, Cl 6 alkoxy, msleimide, propargyl ether, glycidyl ether or phenyl; and A is a polyvalen~ linking moiety which is preferably selected from aromatic, nliphatic, cycloaliphatic, polycyclic, and heteroatomic groups. Most preferred examples of linking moiety A include -0-, -S02-, -C0-, -OCO0-, -S-, -Cl 12-' dicyclopentadienyl, aralkyl, aryl, cycloallphatic and a direct bond.
Such phenolic reactants include, for example, phenol, m-, p-dihydroxy benzene, 2-tert-butyl hydroquinone, 2,4-dimethyl resorcinol, 2,5-di-tert-butyl hydroquinone, tetramethyl hydro-quinone, 2,4,6-trimethyl resorcinol, 2,6-di-tert-butyl hydro-quinone, 4-chlororesorcinol; dihydroxy naphthPlenes such as, for example, 2,4-, 1,5-, 1,6-, 1,7-, 2,6- and 2,7-dihydroxy naphthalene; dihydroxy diphenyls such as for example 4,4'-dihydroxy diphenyl, 2,2'-dihydroxy dlphenyl, 3,3',5,5'-tetramethyl-4,4'-dihydroxy diphenyl, 3,3',5,5'-tetrachloro-4,4'-dihydroxy diphenyl, 3,3', 5,5'-tetrachloro-2,2'-dihydroxy diphenyl, 2,2',6,6'-tetra-chloro-4,4'-dihydroxy diphenyl, 4,4'-bis-[(3-hydroxy)-phenoxy]-diphenyl, 4,4'-bis-[(4-hydroxy)-phenoxy]-diphenyl; 2,2'-dihydroxy-1,1'-binaphthyl; dihydroxy diphenyl ethers such as, for example, 4,4'-dihydroxy diphenyl ether, 3,3', 5,5'-tetramethyl-4,4'-dihydoxy diphenyl ethPr, 3,3',5,5' tetrachloro-4,4'-dihydroxy diphenyl ether, 4,4'-bis-[4-hydroxy phenoxy]-diphenyl ether, 4,4'-bis-[4-hydroxyphenyl isopropyl]-diphenyl ether, 4,4'-bis-[4-hydroxyphenoxy]-benzene, 4,4'-bis-[3-hydroxy phenoxy]-diphenyl ether, 4,4'-bis-[4-(4-hydroxy phenoxy)-phenylsulphone]-diphenyl ether; diphenyl sulphones such as, ~or exa~ple, 4,4'-dihydroxy diphenyl ~ulphone 3,3',5,5' tetra-methyl-4,4'-dihydroxy diphenyl sulphone, 3,3',5,5'-tetrachloro-4,4'-dihydroxy diphenyl sulphone, 4,4'-bis-[4-hydroxy phenyl isopropyl]-diphenyl sulphone, 4,4'-bis-[(4-hydroxy)-phenoxy]-diphenyl sulphone, 4,4'-bis-[(3-hydroxy)-phenoxy]-diphenyl sulphone, 4,4'-bis-[4(4-hydroxy phenyl isopropyl)-phenoxy]-diphenyl sulphone, 4,4'-bis-[4-(4-hydroxy phenyl sulphone)-phenoxy]-diphenyl sulphone, 4,4'-bis-[4-(4-hydroxy)-diphenoxy]-diphenyl sulphone;
dihydroxy diphenyl alkanes such as, for example, 4,4'-dihydroxy diphenyl methane, 4,4'-bis-[4-hydroxy phenyl]-diphenyl methane, 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as BPA), 2,2-bis-(3,5-dimethyl-4-hydroxy phenyl)-propane, 2,2-bis-(3,5-dichloro-4-hydroxy phenyl)-propane, 1,1-bis-l4-hydroxy phenyl]-10cyclohexane, bis-[2-hydroxy-1-naphthyl]-methane, 1,2-bis-[4-hydroxy phenyl]-1,1,2,2-tetramethyl ethane, 4,4'-dihydroxy benzophenone, 4,4'-bis-(4-hydroxy)-phenoxy ben~ophenone, 1,4-bis-[4-hydroxy phenyl isopropyl]-benzene, phloroglucinol and 2,2', 5,5'-tetra-hydroxy diphenyl sulphone.
15Other preferred phenolic reactants are phenolic novolacs, such as BPA novolac and o-cresol novolac. The phenolic novolac may contain substituents as described above, including glycidyl ether, propargyl ether and Cl 6 alkyl groups.
The base employed in the first reaction step can be, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide; an alkali metal alkylate such as sodium methylate or potassium methylate; and various amines.
The preferred base is selected from tertiary amines. Tertiary amines can be represented by the formula R"
I
R' -N -Rn' in which R', R" and R"' represent Cl 36~ preferably Cl 10 alkyl;
aryl such as phenyl; and C4 7 cycloalkyl. ~xamples of cuch tertiary amines include trimethyl amine, triethyl amine, methyl diethyl amine, tripropyl amine, ~ributyl amine, methyl dibutyl amine, dinonyl methyl amine, dimethyl stearyl amine, dimethyl cyclohexyl amine and diethyl aniline. The most preferred tertiary amine is triethylamine.
20222~
In general, although the quantity can vary widely depending on reaction conditions, the base is employed in a quantity of at least 0.7 equivalent, preferably from 0.9 to l.5 equivalents, per hydroxyl ~,roups in the phenolic compound.
The first reaction step will generally be carried out in an organic solvent, including ketones such ~s methyl ethyl ketone, acetone and methyl isobutyl ketone; aliphatic alcohols such as methanol, ethanol, propanol and butanol; amides such as dimethyl formamide and dimethyl acetamide; cyclic ethers such as dLoxane and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene or xylene and mixtures of such or~anic solvents. Water may also be used as a medium for the pre-reaction.
The reaction temperature in the first step can vary depending upon the other reaction conditions, but will generally be carried out at a temperature greater than 30C, preferably within the range of 40 to 80C. Pressure will most conveniently be atmospheric.
The time for completion of the reaction will vary depending upon the other reaction conditions, but will generally be within the range of l to 3 hours.
The second reaction step will be carried out by reacting the salt formed in the first step with a cyanogen halide. The pre-ferred cyanogen halides, because of their a~ailability, are cyanogen chloride and cyanogen bromide. The reaction is preferably carried out in a solvent, such as those described above for the pre-reaction, under an inert atmosphere such as nitrogen gas. The reaction temperature can vary within the range of -20C to the boiling temperature of the reactants, but wlll most conveniently be carried out at a temperature above 20C, preferably within the range of 20 to 60C, most preferably 20 to 45C.
The product cyanate ester is recovered from the reaction mixeure by conventional methods such as filtration, centrifugation, distillation, precipitation or solvent extraction, followed by washing.
In a specific embodiment of the invention process, mixed-functionality aromatic compounds having at least one cyanate ester 20222~ '~
group and at least one propargyl ether group (-OCH2C-CH) are prepared from phenolic compounds having at least one propargyl ether substituent.
To a 250 ml four-neck round-bottom flask equipped with a stirrer, condenser, nitrogen inlet tube, addition funnel and thermocouple were added 14 grams of bisphenol-A dissolved in 70 ml of methyl isobutyl ketone. The temperature was raised to 40C and 12.9 grams of triethylamine were ~dded dropwise. After the addition had been completed, the mixture was heated for one hour at 70C. After heating had been completed, the mixture was trans-ferred to a dropping funnel on another four-neck flask equipped as the first. In the second flask, l9.9 ~rams of cyanogen bromide was added and dissolved with stirring in 50 ml of methyl isobutyl ketone. The temperature was raised to 40C and the salt of triethylamine and BPA was added dropwise over the next two hours.
The course of the reaction was followed by I~. The IR spectrum initially showed the cyanate band of cyanogen bromide at 2220 cm l, followed by the gradual appearance of a band at 2300 cm l representing the cyanate ester of BPA. There was little evidence of the presence of diethylcyanamide, which has an IR band at 2260 cm l. This example confirms that the salt of triethylamine and BPA is converted in the ~econd reaction step into a cyanate ester.
EXAMPLE 2 ~for comparison) A comparison experiment was performed to prepare a cyanate ester without pre-reaction of the triethylamine catalyst with BPA.
The reaction described in Example l was essentially duplicated without the salt formation in the first step. The triethylamine and BPA were d$ssolved in methyl isobutyl ketone at room temperature and added dropwise to cyanogen bromide dissolved $n methyl isobutyl ketone at 40C. The initial IR showed the cyanate band of cyanogen bromide at 2200 c~ followed by the gradual appear-ance of the diethylcyana~ide band at 2260 cm . Unlike the result oi Example l there was little evidence of BPA cyanate formation.
2~2~
To a 250 ml four-neck round-bottom flask equipped with a stirrer, condenser, nitrogen inlet tube, addition funnel and thermocouple were added 14 grams of bisphenol-A dissolved in 70 ml of methyl isobutyl ketone. The temperature was raised to 40C and 12.9 grams of triethylamine were ~dded dropwise. After the addition had been completed, the mixture was heated for one hour at 70C. After heating had been completed, the mixture was trans-ferred to a dropping funnel on another four-neck flask equipped as the first. In the second flask, l9.9 ~rams of cyanogen bromide was added and dissolved with stirring in 50 ml of methyl isobutyl ketone. The temperature was raised to 40C and the salt of triethylamine and BPA was added dropwise over the next two hours.
The course of the reaction was followed by I~. The IR spectrum initially showed the cyanate band of cyanogen bromide at 2220 cm l, followed by the gradual appearance of a band at 2300 cm l representing the cyanate ester of BPA. There was little evidence of the presence of diethylcyanamide, which has an IR band at 2260 cm l. This example confirms that the salt of triethylamine and BPA is converted in the ~econd reaction step into a cyanate ester.
EXAMPLE 2 ~for comparison) A comparison experiment was performed to prepare a cyanate ester without pre-reaction of the triethylamine catalyst with BPA.
The reaction described in Example l was essentially duplicated without the salt formation in the first step. The triethylamine and BPA were d$ssolved in methyl isobutyl ketone at room temperature and added dropwise to cyanogen bromide dissolved $n methyl isobutyl ketone at 40C. The initial IR showed the cyanate band of cyanogen bromide at 2200 c~ followed by the gradual appear-ance of the diethylcyana~ide band at 2260 cm . Unlike the result oi Example l there was little evidence of BPA cyanate formation.
2~2~
Into a 4-neck, 500 ml round-bottom flask equipped with a stirring rod, dropping funnel, nitrogen inlet tube, thermocouple and condenser were sdded 50g (0.22 moles) of BPA and 250 ml methyl isobutyl ketone. The temperature was increased to 60~C, and 45g (0.445 moles) of triethylamine were added dropwise over one hour.
Heating was continued for an additional 1.25 hours.
The reaction mixture was then transferred to a dropping funnel attached to a 2000 ml reaction flask equipped as descr$bed above.
Into the flask were added 69.6g (0.66 moles~ of cyanogen bromide and 200 ml of methyl isobutyl ketone. The mixture was stirred until the cyanogen bromide was dissolved and the temperature was raised to 47nc. The said reaction mixture was added from the dropping funnel to the cyanogen bromide dropwise over an hour. The reaction mixture began to turn cloudy after 30 minutes, and one could visually observe the presence of triethylamine hydrobromide after one hour. The reactlon was stirred without heat overnight.
The prçcipitated triethylamine hydrobromide was removed by filtration and the solvent was vacuum distilled off. Yield of BPA
dicyanate was 90~, based upon recovered triethylamine hydrobromide.
Into a 5000 ml, 4-neck flask equipped with a stirrer, reflux condenser and thermocouple were added 2055g of methyl isobutyl ketone and 240g water. 353.7g of o-cresylic novolac resin having a molecular weight of 625 and average hydroxyl functionality of 5 were added to the flask, which was then heated to 40C. After the o-cresylic novolac resin was co~pletely dissolved, ll9g of 50%
solution of sodium hydroxide in water was slowly added over 40 minutes at 40C. After hydroxite addition was complete, the temperature was raised to 60-C nnd 279g of propargyl chloride were added slowly over 2.7 hours. ~fter propargyl chloride addition was complete, the temperature was increased to reflux (78C) and maintained for 3 hours. The reaction mixture was stirred overnight. The aqueous phase was removed.
217.5g of the organic phase was weighed into a 500 ml 4-neck flask and to this was add~d 12.6g triethylamine at 45C.
20222~4 The resulting solution was divided into two equal portions. Each portion was added dropwise to a solution of 9.9g cyanogen bromide in 30g methyl isobutyl ketone. The temperature of the first solution was maintained at 45~C for 1 hour. The temperature of the second soluti~n was maintained at 60C for 1 hour. Both reaction mixtures were stirred at room temperature overnight. The products were recovered by vacuum distillation. Uncatalyzed gel time of the products (unwashed) were 257 seconds and 66 seconds, respectively.
Each product showed an IR band at 2300 cm
Heating was continued for an additional 1.25 hours.
The reaction mixture was then transferred to a dropping funnel attached to a 2000 ml reaction flask equipped as descr$bed above.
Into the flask were added 69.6g (0.66 moles~ of cyanogen bromide and 200 ml of methyl isobutyl ketone. The mixture was stirred until the cyanogen bromide was dissolved and the temperature was raised to 47nc. The said reaction mixture was added from the dropping funnel to the cyanogen bromide dropwise over an hour. The reaction mixture began to turn cloudy after 30 minutes, and one could visually observe the presence of triethylamine hydrobromide after one hour. The reactlon was stirred without heat overnight.
The prçcipitated triethylamine hydrobromide was removed by filtration and the solvent was vacuum distilled off. Yield of BPA
dicyanate was 90~, based upon recovered triethylamine hydrobromide.
Into a 5000 ml, 4-neck flask equipped with a stirrer, reflux condenser and thermocouple were added 2055g of methyl isobutyl ketone and 240g water. 353.7g of o-cresylic novolac resin having a molecular weight of 625 and average hydroxyl functionality of 5 were added to the flask, which was then heated to 40C. After the o-cresylic novolac resin was co~pletely dissolved, ll9g of 50%
solution of sodium hydroxide in water was slowly added over 40 minutes at 40C. After hydroxite addition was complete, the temperature was raised to 60-C nnd 279g of propargyl chloride were added slowly over 2.7 hours. ~fter propargyl chloride addition was complete, the temperature was increased to reflux (78C) and maintained for 3 hours. The reaction mixture was stirred overnight. The aqueous phase was removed.
217.5g of the organic phase was weighed into a 500 ml 4-neck flask and to this was add~d 12.6g triethylamine at 45C.
20222~4 The resulting solution was divided into two equal portions. Each portion was added dropwise to a solution of 9.9g cyanogen bromide in 30g methyl isobutyl ketone. The temperature of the first solution was maintained at 45~C for 1 hour. The temperature of the second soluti~n was maintained at 60C for 1 hour. Both reaction mixtures were stirred at room temperature overnight. The products were recovered by vacuum distillation. Uncatalyzed gel time of the products (unwashed) were 257 seconds and 66 seconds, respectively.
Each product showed an IR band at 2300 cm
Claims (4)
1. A process for preparing a cyanate ester comprising the steps of:
(a) reacting a phenolic compound w1th a base to produce a salt of said phenolic compound and said base; and (b) reacting said salt with a cyanogen halide, and recovering a cyanate ester from the reaction mixture.
(a) reacting a phenolic compound w1th a base to produce a salt of said phenolic compound and said base; and (b) reacting said salt with a cyanogen halide, and recovering a cyanate ester from the reaction mixture.
2. The process of claim 1 in which the phenolic compound has the formula in which each a and b is independently 0, 1, 2 or 3 and at least one a is not 0, the sum of a + b equalling at most 5 in each of the terminal phenyl groups and equalling at most 4 in each of the internal phenylene groups; n is from 0 to 8; each R is selected independently from hydrogen, C1-6 alkyl, C1-6 allyl, halogen, C1-6 alkoxy, maleimide, propargyl ether, glycidyl ether, or phenyl; and A is a divalent linking moiety.
3. The process of claim 1 or 2 in which the base is a tertiary amine selected from the group consisting of trimethyl amine, triethyl amine, methyl diethyl amine, tripropyl amine, tributyl amine, methyl dibutyl amine, dinonyl methyl amine, dimethyl stearyl amine, dimethyl cyclohexyl amine and diethyl aniline.
4. The process of any one of claims 1 to 3 in which the phenolic compound is hydroxy benzene, dihydroxy benzene, 2,2-bis(4-hydroxy-phenyl)propane or a phenolic novolac.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/387,268 US4981994A (en) | 1989-07-31 | 1989-07-31 | Preparation of cyanate esters |
| US387,268 | 1989-07-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2022214A1 true CA2022214A1 (en) | 1991-02-01 |
Family
ID=23529166
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002022214A Abandoned CA2022214A1 (en) | 1989-07-31 | 1990-07-30 | Preparation of cyanate esters |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4981994A (en) |
| EP (1) | EP0411707A1 (en) |
| JP (1) | JPH0366653A (en) |
| KR (1) | KR910002779A (en) |
| CA (1) | CA2022214A1 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5284968A (en) * | 1986-11-24 | 1994-02-08 | Ciba-Geigy Corporation | Process for preparing bis (4-cyanatophenyl)-1,1-ethane |
| US5162574A (en) * | 1986-11-24 | 1992-11-10 | Hi-Tek Polymers, Inc. | Bis(4-cyanatophenyl)-1,1-ethane |
| US5149863A (en) * | 1990-03-29 | 1992-09-22 | Hi-Tek Polymers, Inc. | Low temperature curable dicyanate esters of dihydric phenols |
| US5292861A (en) * | 1992-12-29 | 1994-03-08 | International Business Machines Corporation | Trifunctional cyanate esters, polymers thereof; use and preparation thereof |
| US5756592A (en) * | 1995-11-27 | 1998-05-26 | Alliedsignal, Inc. | Process for the production of cyanate ester resins having unique composition |
| CH693744A5 (en) | 1998-08-20 | 2004-01-15 | Sumitomo Chemical Co | A process for producing highly pure aromatic cyanate. |
| DE19947613A1 (en) | 1998-10-07 | 2000-04-13 | Sumitomo Chemical Co | Purification of cyanate useful e.g. as sealant, composite, molding composition or adhesive for electronic components uses poor solvent containing alcohol and water in crystallization or precipitation from crude solution |
| US7057264B2 (en) * | 2002-10-18 | 2006-06-06 | National Starch And Chemical Investment Holding Corporation | Curable compounds containing reactive groups: triazine/isocyanurates, cyanate esters and blocked isocyanates |
| JP2013173838A (en) * | 2012-02-24 | 2013-09-05 | Dic Corp | Cyanic ester resin, curable resin composition, cured matter thereof, semiconductor sealing material, prepreg, circuit board and build-up film |
| JP6098908B2 (en) * | 2016-01-19 | 2017-03-22 | Dic株式会社 | Curable resin composition, cured product thereof, semiconductor sealing material, prepreg, circuit board, and build-up film |
| US11319421B1 (en) * | 2019-10-21 | 2022-05-03 | United States Of America As Represented By The Secretary Of The Air Force | Microfluidic flow process for making monomers |
Family Cites Families (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3107261A (en) * | 1958-11-28 | 1963-10-15 | Bayer Ag | Process for the production of phenyl cyanates and phenyl cyanates |
| GB877840A (en) * | 1958-11-28 | 1961-09-20 | Bayer Ag | Phenyl cyanates and a process for their production |
| US3595900A (en) * | 1968-07-01 | 1971-07-27 | Minnesota Mining & Mfg | Cyanatophenyl-terminated polyarylene ethers |
| US4029649A (en) * | 1970-10-20 | 1977-06-14 | Ciba-Geigy Corporation | Terpene aryl esters |
| US3761501A (en) * | 1971-06-02 | 1973-09-25 | Allied Chem | Perfluoroalkyl cyanates |
| US3876607A (en) * | 1972-09-13 | 1975-04-08 | John B Snell | Epoxy compositions |
| US4170711A (en) * | 1974-03-12 | 1979-10-09 | General Electric Company | Brominated biphenol derivatives |
| JPS5114995A (en) * | 1974-07-29 | 1976-02-05 | Mitsubishi Gas Chemical Co | Shiansanesuterukiganjufuenoorujushino seizohoho |
| DE2446004C3 (en) * | 1974-09-26 | 1980-01-10 | Bayer Ag, 5090 Leverkusen | Process for the production of particularly pure aromatic cyanic acid esters |
| DE2507746A1 (en) * | 1975-02-22 | 1976-09-02 | Bayer Ag | AROMATIC CYANIC ACID ESTER |
| DE2507671A1 (en) * | 1975-02-22 | 1976-09-02 | Bayer Ag | Polyvalent aromatic cyanate ester prepn. - by halogen cyanide reaction with di-or polytrialkyl ammonium phenolate |
| DE2529487C2 (en) * | 1975-07-02 | 1984-12-13 | Bayer Ag, 5090 Leverkusen | Process for the production of high-purity, polyvalent cyanic acid esters |
| US4028393A (en) * | 1975-02-22 | 1977-06-07 | Bayer Aktiengesellschaft | Process for the production of polyfunctional cyanic acid esters |
| US4046796A (en) * | 1975-02-22 | 1977-09-06 | Bayer Aktiengesellschaft | Process for the production of polyfunctional cyanic acid esters |
| JPS51114494A (en) * | 1975-04-02 | 1976-10-08 | Mitsubishi Gas Chem Co Inc | Preparation of cyanic acid eaters of aromatic polycarbonate |
| US4226800A (en) * | 1979-06-14 | 1980-10-07 | The United States Of America As Represented By The Secretary Of The Air Force | Synthesis of acetylene-terminated compounds |
| US4713442A (en) * | 1983-11-16 | 1987-12-15 | The Dow Chemical Company | Polyaromatic cyanate |
| US4740584A (en) * | 1986-09-08 | 1988-04-26 | Interez, Inc. | Blend of dicyanate esters of dihydric phenols |
| US4749760A (en) * | 1987-06-30 | 1988-06-07 | Shell Oil Company | Curable resin compositions |
| US4806625A (en) * | 1988-01-12 | 1989-02-21 | The Dow Chemical Company | Flame resistant polyaromatic cyanate resins with improved thermal stability |
-
1989
- 1989-07-31 US US07/387,268 patent/US4981994A/en not_active Expired - Fee Related
-
1990
- 1990-07-27 EP EP90202075A patent/EP0411707A1/en not_active Ceased
- 1990-07-30 KR KR1019900011593A patent/KR910002779A/en not_active Application Discontinuation
- 1990-07-30 JP JP2199340A patent/JPH0366653A/en active Pending
- 1990-07-30 CA CA002022214A patent/CA2022214A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| EP0411707A1 (en) | 1991-02-06 |
| JPH0366653A (en) | 1991-03-22 |
| US4981994A (en) | 1991-01-01 |
| KR910002779A (en) | 1991-02-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |