CA1149415A - Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde - Google Patents
Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehydeInfo
- Publication number
- CA1149415A CA1149415A CA000406536A CA406536A CA1149415A CA 1149415 A CA1149415 A CA 1149415A CA 000406536 A CA000406536 A CA 000406536A CA 406536 A CA406536 A CA 406536A CA 1149415 A CA1149415 A CA 1149415A
- Authority
- CA
- Canada
- Prior art keywords
- diacetate
- acetate
- toluene
- formaldehyde
- hydroquinone
- 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
Links
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSUR
Equimolar amounts of phenol and formaldehyde may be prepared from oxygen and toluene. The catalytic oxidation of toluene, when carried out in the presence of acetic anhydride, forms phenyl acetate and methylene diacetate. Pyrolycis of these two intermediates yields phenol and formaldehyde.
Significant improvements in this process are achieved when the first stage of the reaction is carried out in the presence of MoO3.
In a further embodiment of this invention it has been found that Group VIII dithiosemibenzil compounds, part-icularly nickel dithiosemibenzil, serves as a superior pro-moter for the toluene oxidation reaction.
In still a further embodiment of this invention it has been found that persulfate promoters such as potassium persulfate, persulfuric acid, or Caro's dry acid are parti-cularly effective promoters for the toluene oxidation reaction.
In a like manner, hydroquinone or resorcinol may be obtained from cresyl acetates.
In a further embodiment of this invention it has been found that benzylidene acetate may be converted to phenyl acetate and methylene diacetate by acid-catalyzed reaction in the presence of oxygen and acetic anhydride.
Equimolar amounts of phenol and formaldehyde may be prepared from oxygen and toluene. The catalytic oxidation of toluene, when carried out in the presence of acetic anhydride, forms phenyl acetate and methylene diacetate. Pyrolycis of these two intermediates yields phenol and formaldehyde.
Significant improvements in this process are achieved when the first stage of the reaction is carried out in the presence of MoO3.
In a further embodiment of this invention it has been found that Group VIII dithiosemibenzil compounds, part-icularly nickel dithiosemibenzil, serves as a superior pro-moter for the toluene oxidation reaction.
In still a further embodiment of this invention it has been found that persulfate promoters such as potassium persulfate, persulfuric acid, or Caro's dry acid are parti-cularly effective promoters for the toluene oxidation reaction.
In a like manner, hydroquinone or resorcinol may be obtained from cresyl acetates.
In a further embodiment of this invention it has been found that benzylidene acetate may be converted to phenyl acetate and methylene diacetate by acid-catalyzed reaction in the presence of oxygen and acetic anhydride.
Description
Background of the Invention This invention relates to a process for the oxida-tion of toluene. More particularly, this invention relates to a novel process for the oxidation of toluene to ultimately yield phenol and formaldehyde or paraformaldehyde in equimolar amounts. In a like manner, cresyl acetates may be oxidized to obtain hydroquinone or resorcinol.
` It is known from Grozhan et al, Dokladv Akad. Nauk SSSR, 204, No. 4,872, and Russian ~atents 329,167 (1972) and 321,518 (1971) that when toluene is oxidized in the presence of acetic anhydride and acid, followed by saponification of the total reaction product, phenol is formed in substantial quantities, together with lesser amounts of benzaldehyde, benzyl acetate and other related materials. Cbunterpart 8ritish Patent 1,244,080, from the same Russian ~ources, teaches a like process and further proposes a mechani~m whereby through the formation and rearrangement of a hydro-peroxide intermediate, both phenol and an aliphatic aldehyde or ketone ~re produced.
` It is known from Grozhan et al, Dokladv Akad. Nauk SSSR, 204, No. 4,872, and Russian ~atents 329,167 (1972) and 321,518 (1971) that when toluene is oxidized in the presence of acetic anhydride and acid, followed by saponification of the total reaction product, phenol is formed in substantial quantities, together with lesser amounts of benzaldehyde, benzyl acetate and other related materials. Cbunterpart 8ritish Patent 1,244,080, from the same Russian ~ources, teaches a like process and further proposes a mechani~m whereby through the formation and rearrangement of a hydro-peroxide intermediate, both phenol and an aliphatic aldehyde or ketone ~re produced.
-2-... . ~ , .... .. . ... . .. ... ..... .... . .. . . . . .. ..... .. . . . . .
1~4'3~.15 Significantly, there is no mention or suggestion of the formation of methylene diacetate, and therefore obviously no teaching of converting æaid methylene diacetate to form-aldehyde. Moreover, the Russian work is silent as to the use of any promoters or other adjuvants in addition to acid catalysts which would serve to enhance the rate, yield, or selectivity of this oxidation reaction.
SummarY of the rnvention In accordance with the present invention there is provided a novel process for the oxidation of toluene to ultimately yield eguimolar amounts of phenol and formaldehyde or paraformaldehyde. In general, this is achieved by oxidiz-ing toluene with air or oxygen at selected pressures and temperatures in the liquid phase in the presence of acetic anhydride and a strong acid catalyst to form phenyl acetate and methylene diacetate in equal amounts together with acetic acid. The methylene diacetate and phenyl acetate are separated by distillation of the reaction product. The phenyl acetate is then pyrolyzed to form phenol and ketene, while the methylene diacetate is pyrolyzed to form formaldehyde and acetic anhydride. The acetic acid and ketene may then be con-verted to acetic anhydride by known methods and recycled to the oxidation step.
The oxidation step is further characterized, in accordance with this invention, by the use of molybdenum trioxide for purposes of suppressing the formation of un-wanted CO2, or by the use of Group VIII dithiosemibenzil com-pounds or persulfates as promoters for the oxidation reaction.
Optionally, these additives may be employed simultaneously.
34 ~5 Finally this process is also characterized by the use of certain select temperatures and pressures which further enhance the yield of the desired products.
Description of the Drawing Figure 1 is a block flow diagram which shows each aspect of the overall reaction from toluene to final products.
Description of the Reaction As aforementioned, the first step of this process is the liquid phase oxidation of toluene using a strong acid catalyst to form phenyl acetate and methylene diacetate.
This reaction may be illustrated as follows:
PhCH3 + 2 + 2AC2~ H2SO4 > PhOAc I CH2(OAc)2 + HOAc wherein the weight ratio of toluene to acetic anhydride is in the range of from about 50:1 to 1:10, and prefe~ably 10:1 to 2:1, while the ratio of H2SO4 to toluene employed is from about 5 x 10 4 to 1 x 10 2, and preferably 1 x 10 3 to 5 ~ 10 3.
The reaction, which employs oxygen or equiYalent amounts of air, should be carried out at temperatures in the range of from about 140 to 300C, and preferably about 150 to 250C, and at initial pressures of from about 50 to 450 psig. The pressure is desirably generated by charging to an autocla~e air or mixtures of oxygen and nitrogen having an oxygen/nitrogen ratio of from 10:1 to 1:20 psig. The reaction mixture is then heated and the reactor pressure rises accord-ingly.
The reaction may be run in excess toluene as a ~ 14~3~
solvent or in organic solvents such as benzene, chlorobenzene, or acetic acid. Carrying out the reaction in inert sol~ents such as benzene or chlorobenzene does not appreciably affect yield or selectivity but when acetic acid is employed, sig-nificantly increased selectivities may be observed. In order for rapid reactions in acetic acid, promoters such as Caro's dry acid should be e~ployed.
It has been discovered that for purposes of pro-viding a smoothly catlayzed reaction without the formation of considerable quantities of unwanted C02 by-product, there should desirably be employed in the course of this reaction MoO3. This oxide is preferably added in amounts of 19 3 to 10 29 per gram of toluene.
In a further embodiment of this invention it has also been found that when a Group VIII dithiosemibenzil complex, such as nickel dithiosemibenzil is added to the reaction it serves as a promoter for the oxidation, thereby increasing the extent of reaction. This promoter is desirably used in amounts of from about 10 3 to 10 2g per gram of toluene.
If desired, both the MoO3 catalyst and the promoters may be used jointly, although this is not essential. However, enhanced results are generally obtained thereby.
The reaction product containing phenyl acetate and methylene diacetate, as well as lesser amounts of such pro-ducts as benzyl acetate and benzylidene diacetate is then routinely treated to remove the acid catalyst therefrom. The phenyl acetate and methylene diacetate are then separated by distillation under vacuum.
~l ~9al5 The recovered phenyl acetate i8 then converted to phenol and ketene by pyrolysis. This is conventionally achieved by heating the phenyl acetate at temperatures of from about S00 to 1000C, preferably at about 625C, pre-ferably in the presence of a catalyst such as triethylphos-phate, and separating the effluent phenol and ketene by con-ventional means.
In a like manner, the pyrolysis of methylene diacetate yields formaldehyde and acetic anhydride. This pyro-lysis is conventionally carried out in one step in a homo-geneous gas phase reaction, at about 450-550C under reduced pressure. The ketene recovered from the phenyl acetate pyro-lysis, together with the acetic acid recovered from the oxida-tion of the toluene, may then be converted to acetic anhydride for recycling to the initial oxidation step. This is readily achieved by contacting the gaseous ketene with acetic acid at room temperature in the liquid phase.
It has ~een discovered that one of the by-products of the toluene oxidation, benzylidene diacetate, can be con-verted to phenyl acetate and methylene diacetate and there-fore may be recycled to enhance overall product yields. This reaction is novel and proceeds by a route which does not have precedent in the literature.
The reaction of benzylidene diacetate to give methylene diacetate and phenyl acetate may be carried out under elevated temperatures of from about 150 to 250C, pre-ferably 200 to 220C, and initial pressures at room temperature, ~49~15 ' of from about 100 to 300 psig, of an O2-containing gas, pre-ferably 190 to 220 psig, in an augocla~e for periods ranging from about 15 minutes to 4 hours, depending upon the pressures and temperatures employed.
The benzylidene diacetate, (5-25 wt.%) should desirably be reacted in a solvent such as benzene. The acetic anhydride should desirably be present in amounts of 2-3 times by weight of the amount of banzylidene diacetate used. The amount of acid catalyst employed should be in con-centrations ranging from about 10 1 to 10 2, preferably 2 x 10 2 to 4 x 10 2, moles/liter.
Air may be used in place f 2~ in which case the amounts are increased proportionatly to provide an equivalent amount of 2 The acid catalyst is desirably sulfuric acid, but other like acids such as peroxymonosulfuric acid, Caro's dry reagent, or mixtures thereof, may be used instead.
If desired, small amounts of initiators such as azobisisobutyronitrile, dibenzoylperoxide and the li~e may be added to help initiate the reaction. Generally, 0.2 wt.~, is sufficient for this purpose.
The following examples are provided to illustrate, but not to limit, the scope of the invention described here-irl .
~i~9~
The following examples are provided solely forpurposes of illustrating but not limiting the novel process of this invention.
The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene240 m mole acetic anhydride120 m mole H SO4 1 m le N22 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time rapid cooling was accomplished first ~y air, then by cold water immersion. This was followed by analysis of both the gas and liquid phases. Mass spectrometric analysis of the gas phase together with measurement of pressure decrease showed that the ratio of moles of CO2 produced to moles of 2 consumed was 0.21.
Standardized gas chromatographic analysis of the liguid phase showed that toluene conversion was 9%, and ~60%
of the acetic anhydride had been consumed.
Product selectivities (%) basea on toleune conver-ted were:
Phenyl acetate 52 Methylene diacetate 52 o-methyl phenyl acetate 4 Denzyl acetate 16 phenoxymethylene acetate 6 benzylidene di~cetate 6 tars and other~ 16 10~
The following ingredients were charged to a 300 ml rocking ~149~
~toclave reactor:
toluene 240 m mole acetic anhydride 120 m mole H2SO4 1 m mole MoO3 0.1 g ~2 230 psi 2 60 psi The temperature was rapidly raised to 201C where it was maintained for one hour. At the end of this time, the product was wor~ed up in accordance with the procedures of Example 1. The ratio of moles of CO2 produced to moles f 2 consumed was 0.08.
Standardized gas chromatographic analysis of the liquid phase showed that toleune conversion was 10%.
Product selectivities (%) based on toleune converted were:
phenyl acetate 54methylene diacetate 54 o-methyl phenyl acetate 4 benzyl acetate 15 phenoxymethylene acetate 6 benzylidene diacetate 6 tars and others 15 The following ingredients were charged to a 300 ml roc~ing autoclave reactor:
toluene 240 m mole acetic anhydride 120 m mole H2SO4 1 m mole
1~4'3~.15 Significantly, there is no mention or suggestion of the formation of methylene diacetate, and therefore obviously no teaching of converting æaid methylene diacetate to form-aldehyde. Moreover, the Russian work is silent as to the use of any promoters or other adjuvants in addition to acid catalysts which would serve to enhance the rate, yield, or selectivity of this oxidation reaction.
SummarY of the rnvention In accordance with the present invention there is provided a novel process for the oxidation of toluene to ultimately yield eguimolar amounts of phenol and formaldehyde or paraformaldehyde. In general, this is achieved by oxidiz-ing toluene with air or oxygen at selected pressures and temperatures in the liquid phase in the presence of acetic anhydride and a strong acid catalyst to form phenyl acetate and methylene diacetate in equal amounts together with acetic acid. The methylene diacetate and phenyl acetate are separated by distillation of the reaction product. The phenyl acetate is then pyrolyzed to form phenol and ketene, while the methylene diacetate is pyrolyzed to form formaldehyde and acetic anhydride. The acetic acid and ketene may then be con-verted to acetic anhydride by known methods and recycled to the oxidation step.
The oxidation step is further characterized, in accordance with this invention, by the use of molybdenum trioxide for purposes of suppressing the formation of un-wanted CO2, or by the use of Group VIII dithiosemibenzil com-pounds or persulfates as promoters for the oxidation reaction.
Optionally, these additives may be employed simultaneously.
34 ~5 Finally this process is also characterized by the use of certain select temperatures and pressures which further enhance the yield of the desired products.
Description of the Drawing Figure 1 is a block flow diagram which shows each aspect of the overall reaction from toluene to final products.
Description of the Reaction As aforementioned, the first step of this process is the liquid phase oxidation of toluene using a strong acid catalyst to form phenyl acetate and methylene diacetate.
This reaction may be illustrated as follows:
PhCH3 + 2 + 2AC2~ H2SO4 > PhOAc I CH2(OAc)2 + HOAc wherein the weight ratio of toluene to acetic anhydride is in the range of from about 50:1 to 1:10, and prefe~ably 10:1 to 2:1, while the ratio of H2SO4 to toluene employed is from about 5 x 10 4 to 1 x 10 2, and preferably 1 x 10 3 to 5 ~ 10 3.
The reaction, which employs oxygen or equiYalent amounts of air, should be carried out at temperatures in the range of from about 140 to 300C, and preferably about 150 to 250C, and at initial pressures of from about 50 to 450 psig. The pressure is desirably generated by charging to an autocla~e air or mixtures of oxygen and nitrogen having an oxygen/nitrogen ratio of from 10:1 to 1:20 psig. The reaction mixture is then heated and the reactor pressure rises accord-ingly.
The reaction may be run in excess toluene as a ~ 14~3~
solvent or in organic solvents such as benzene, chlorobenzene, or acetic acid. Carrying out the reaction in inert sol~ents such as benzene or chlorobenzene does not appreciably affect yield or selectivity but when acetic acid is employed, sig-nificantly increased selectivities may be observed. In order for rapid reactions in acetic acid, promoters such as Caro's dry acid should be e~ployed.
It has been discovered that for purposes of pro-viding a smoothly catlayzed reaction without the formation of considerable quantities of unwanted C02 by-product, there should desirably be employed in the course of this reaction MoO3. This oxide is preferably added in amounts of 19 3 to 10 29 per gram of toluene.
In a further embodiment of this invention it has also been found that when a Group VIII dithiosemibenzil complex, such as nickel dithiosemibenzil is added to the reaction it serves as a promoter for the oxidation, thereby increasing the extent of reaction. This promoter is desirably used in amounts of from about 10 3 to 10 2g per gram of toluene.
If desired, both the MoO3 catalyst and the promoters may be used jointly, although this is not essential. However, enhanced results are generally obtained thereby.
The reaction product containing phenyl acetate and methylene diacetate, as well as lesser amounts of such pro-ducts as benzyl acetate and benzylidene diacetate is then routinely treated to remove the acid catalyst therefrom. The phenyl acetate and methylene diacetate are then separated by distillation under vacuum.
~l ~9al5 The recovered phenyl acetate i8 then converted to phenol and ketene by pyrolysis. This is conventionally achieved by heating the phenyl acetate at temperatures of from about S00 to 1000C, preferably at about 625C, pre-ferably in the presence of a catalyst such as triethylphos-phate, and separating the effluent phenol and ketene by con-ventional means.
In a like manner, the pyrolysis of methylene diacetate yields formaldehyde and acetic anhydride. This pyro-lysis is conventionally carried out in one step in a homo-geneous gas phase reaction, at about 450-550C under reduced pressure. The ketene recovered from the phenyl acetate pyro-lysis, together with the acetic acid recovered from the oxida-tion of the toluene, may then be converted to acetic anhydride for recycling to the initial oxidation step. This is readily achieved by contacting the gaseous ketene with acetic acid at room temperature in the liquid phase.
It has ~een discovered that one of the by-products of the toluene oxidation, benzylidene diacetate, can be con-verted to phenyl acetate and methylene diacetate and there-fore may be recycled to enhance overall product yields. This reaction is novel and proceeds by a route which does not have precedent in the literature.
The reaction of benzylidene diacetate to give methylene diacetate and phenyl acetate may be carried out under elevated temperatures of from about 150 to 250C, pre-ferably 200 to 220C, and initial pressures at room temperature, ~49~15 ' of from about 100 to 300 psig, of an O2-containing gas, pre-ferably 190 to 220 psig, in an augocla~e for periods ranging from about 15 minutes to 4 hours, depending upon the pressures and temperatures employed.
The benzylidene diacetate, (5-25 wt.%) should desirably be reacted in a solvent such as benzene. The acetic anhydride should desirably be present in amounts of 2-3 times by weight of the amount of banzylidene diacetate used. The amount of acid catalyst employed should be in con-centrations ranging from about 10 1 to 10 2, preferably 2 x 10 2 to 4 x 10 2, moles/liter.
Air may be used in place f 2~ in which case the amounts are increased proportionatly to provide an equivalent amount of 2 The acid catalyst is desirably sulfuric acid, but other like acids such as peroxymonosulfuric acid, Caro's dry reagent, or mixtures thereof, may be used instead.
If desired, small amounts of initiators such as azobisisobutyronitrile, dibenzoylperoxide and the li~e may be added to help initiate the reaction. Generally, 0.2 wt.~, is sufficient for this purpose.
The following examples are provided to illustrate, but not to limit, the scope of the invention described here-irl .
~i~9~
The following examples are provided solely forpurposes of illustrating but not limiting the novel process of this invention.
The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene240 m mole acetic anhydride120 m mole H SO4 1 m le N22 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time rapid cooling was accomplished first ~y air, then by cold water immersion. This was followed by analysis of both the gas and liquid phases. Mass spectrometric analysis of the gas phase together with measurement of pressure decrease showed that the ratio of moles of CO2 produced to moles of 2 consumed was 0.21.
Standardized gas chromatographic analysis of the liguid phase showed that toluene conversion was 9%, and ~60%
of the acetic anhydride had been consumed.
Product selectivities (%) basea on toleune conver-ted were:
Phenyl acetate 52 Methylene diacetate 52 o-methyl phenyl acetate 4 Denzyl acetate 16 phenoxymethylene acetate 6 benzylidene di~cetate 6 tars and other~ 16 10~
The following ingredients were charged to a 300 ml rocking ~149~
~toclave reactor:
toluene 240 m mole acetic anhydride 120 m mole H2SO4 1 m mole MoO3 0.1 g ~2 230 psi 2 60 psi The temperature was rapidly raised to 201C where it was maintained for one hour. At the end of this time, the product was wor~ed up in accordance with the procedures of Example 1. The ratio of moles of CO2 produced to moles f 2 consumed was 0.08.
Standardized gas chromatographic analysis of the liquid phase showed that toleune conversion was 10%.
Product selectivities (%) based on toleune converted were:
phenyl acetate 54methylene diacetate 54 o-methyl phenyl acetate 4 benzyl acetate 15 phenoxymethylene acetate 6 benzylidene diacetate 6 tars and others 15 The following ingredients were charged to a 300 ml roc~ing autoclave reactor:
toluene 240 m mole acetic anhydride 120 m mole H2SO4 1 m mole
3 0.1 g Ni dithiosemibenzil0.15 m mole N2 230 psi 2 60 psi _g_ ~14~1$
The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time, the product was worked up in accordance with the procedures of Example 1. The ratio of moles of CO2 produced to the moles of 2 consumed was 0.10.
Standardized gas chromatographic analysis of the liquid phase showed that toluene conversion was 16%.
Product selectivities (~) based on toluene con-verted were:
phenyl acetate 50methylene diacetate 51 o-methyl phenyl acetate 4 ben2yl acetate 18 phenoxymethylene acetate 8 benzylidene diacetate 6 tars and others 14 A comparison of the CO2/O2 ratio of Example 1 with that of Examples 2 and 3 clearly demonstrates the effective-ness of MoO3 in suppressing CO2 formation.
The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene 240 m mole acetic anhydride 120 m mole ~2S4 1 m mole CrO3 0.1 g ~2 230 psi 2 60 psi The temperature was rapidly raised to 202C where it was maintained for one hour. At the end of this time, the product was wor~ed up in accordance with the procedures of Example 1. The ratio of moles of CO2 produced to the moles .. .. .
~1~9~ t.~i ' f,2 consumed was ~0.3.
Standardized gas chromatographic analysis of the liquid phase showed that toluene conversion was }1%.
Product selectivities (%) based on toluene converted were:
.
phenyl acetate 20methylene diacetate 19 o-methyl phenyl acetate 5 benzyl acetate 36 phenoxymethylene acetate 12 benzylidene diacetate 16 tars and others 11 The following ingredients were charged to a 300 ml roc~ing autoclave reactor:
toluene 240 m mole acetic anhydride 120 m mole H2SO4 1 m mole wo3 0.1 g N2 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time the product was worked up in accordance with the procedures of Example 1. The ratio of moles of C02 produced to the moles f 2 consumed was 0.25.
Standardized gas chromatigraphic analysis of the liquid phase showed that toluene conversion was 8%.
Product selectivities (%) based on toluene converted wexe:
~149~
phenyl acetate35 methylene diacetate 50 o-methyl phenyl acetate 2 ~enzyl acetate 35 phenoxymethylene acetate 3 benxyldene diacetate 4 tars and others 21 A comparison of the selectivities of Examples 2 and 3, where MoO3 was employed, with the results obtained from CrO3 and W03 in Examples 4 and 5, will reveal that MoO3 is far superior to these other metals for purposes of obtain-ing the desired phenyl acetate and methylene diacetate. In addition the MoO3 provided a smoothly catalyzed reaction with little burn to C02 whereas in the cases of CrO3 and W03, 2.5 to 4.0 times as much CO2 was produced.
The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene240 m mole acetic anhydride120 m mole H2S04 1 m mole K2S28 0.1 g N2 230 psi 2 60 psi The temperature was rapidly raised to 201C where it was maintained for one hour. At the end of this time, the product was worked up in accordance with the procedures of Example 1.
Standardized gas chromatographic analysis of the liquid phase showed that toluene conversion was 16~.
Product selectivities (%) based on toluene converted were:
3~ t ~l phenyl acetate54 methylene diacetate 51 o-methyl phenyl acetate4 benzyl acetate 15 phenoxymethylene acetate 6 benzylidene diacetate 6 tars and others 15 - ioo EXA~SPLE 7 The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene240 m mole acetic anhydride 120 m mole H2SO41 m mole Dry Caro's acid0.5 g N2 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time, the product was worked up in accordance with the procedures of Example 1.
.
Standardized gas chromotographic analysis of the liquid phase showed that toluene conversion was 18%.
Product selectivities (%) based on toluene converted were:
phenyl acetate55 methylene diacetate S4 o-methyl phenyl acetate 4 benzyl acetate 13 phenoxymethylene acetate 6 benxylidene diacetate6 tars and others - 16 loo The following ingredients were charged to a 300 ml rocking autoclave re2ctor:
`
~i ~9~ ~5 toluene160 m mole acetic acid80 m mole ~cetic anhydride120-m mole Dry Caro's Acid0.5 g N2 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for 1.5 hours. At the end of this time the product was worked up in accordance with the procédures of Example 1. Toluene conversion was 8%. Product selectivities % based on toluene were:
phenyl acetate 56%
methylene diacetate 58%
benzyl acetate 9%
others 35%
Pyrolysis of methylene diacetate to paraformalde-hyde and acetic anhydride is accomplished thermally at about 500C in a known manner.
Alternatively, the catalytic pyrolysis of methylene diacetate is carried out at about 300C in the presence of a catalyst c,omposed of 5% sodium chloride mixed with silica gel dried and calcined. The methylene diacetate, dissolved in n-hexane, is passed through a passified tubular reactor packed with the catalyst at a space velocity of 900 hr 1 and a temperature of 300C. ParaformaIdehyde and acetic anhydride condense downstream and are separated routinely. Selectivi-ties exceed 93~ for acetic anhydride and 95~ for methylene diacetate.
Pyrolysis of phenyl acetate to phenol and ketene is , ,, , .. .. , .. , . . - .
9~
accomplished thermally at 625C by passing it through a well-conditioned tubular reactor. The effluent is condensed to give 84% yield of phenol and 89% yield of ketene.
The reaction may be carried out at a somewhat lower temperature in the presence of triethyl phosphate catalyst at space velocities of between 900 and 1000 hr 1. Yields in excess of 90% are obtained.
Gaseous ketene obtained from phenyl acetate pyrolysis reacts exothermically with acetic acid (distilled from the oxidation reaction product) in a scrubber reactor with sufficient heat remo~al capacity. Heat of reaction is 15 kcal/mole. The reaction is carried out in two stages at 30-40C and pressures of 50-150 mm Hg. Conversions of acetic acid a~d ketene to acetic anhydride are 90% and 98% respect-ively. Selectivity to acetic anhydride exceeds 95%.
In a further embodiment of this invention it has been found that in a manner similar to the above-described process, hydroquinone or resorcinol, and formaldehyde can be co-produced in several steps from p-xylene or m-xylene respectively. For example, p-xylene can be oxidized to p-cresyl acetate in a known manner which can be oxidized further to hydroquinone diacetate in accordance with the process of this in~ention. The oxidation of each methyl group liberates one molecule of methylene diacetate. Hydroquinone diacetate can be saponified to give hydroquinone and acetic acid.
In this context, it has been found that persulfate , , . ., - . . - - -promoters enhance the rate and selectivity of oxidation of more complex methyl aromatics such as p-cresyl acetate far more dramatically than they enhance toluene oxidation. For example, it has been found that p-cresyl acetate is oxidized very poorly at 200C in the presence of strong acid and acetic anhydride in the absence of persulfate promoters.
Bashkirov (British Patent 1,244,080) found that it was necessary to elevate the reaction temperature to 230C to achieve oxidation of p-cresyl acetate in the presence of acetic anhydride and selectivity (20%) was very low. The instant process now achieves selectivities to hydroquinone precursors of greater than 60% at temperatures no higher than 200C using persulfate promoters, and in addition will isolate methylene diacetate as a co-product in equimolar amounts. The ability to recover methylene diacetate in equimolar amounts in all of these cases is of considerable practical value since one does not lose or waste the methyl group (as CO2) but converts it to a valuable chemical product while at the same time producing the desired phenolic precursor.
The aforementioned persulfate promoter, in one form, can be obtained by admixing potassium persulfate with sodium ~isulfate.
Para-cresyl acetate, 25 ml, benzene, 25 ml, sulf~ric acid, 0.12 gram, sodium bisulfate, 0.20 gram, potassium persulfate, 0.20 gram and acetic anhydride, 6.0 ml, were charged to a rocking autoclave and then 290 pounds of a 20/80 oxygen~nitrogen mixture was admitted. The bomb was rocked ~i4'3~5 for 90 minutes at 200C, cooled, opened and the products analyzed by glpc. Parà-cresyl acetate was converted (10%) tQ
methylene diacetate (40% selectivity) hydroquinone diacetate (63%-selectivity) and other by-products of oxidation. Select-ivities were based on ~-cresyl acetate converted.
Para-cresyl acetate, 25 ml, benzene, 25 ml, sulfuric acid, 0.06 gram, sodium bisulfate, 0.10 gram, potassium persulfate, 0.10 gram and acetic anhydride 6.0 ml were charged to a rocking autoclave and then 290 pounds of a 20/80 oxygen/nitrogen mixture was admitted. The bomb was rocked for 90 minutes at 200C, cooled, opened and the products analyzed by glpc. Para-cresyl acetate was converted (6%) to methylene diacetate (33% selectivity), hydroquinone diacetate (59% selectivity) and other products.
E ~PLE 14 Meta-cresyl acetate was oxidized in the manner of Example 1 to give methylene diacetate and resorcinol diacetate together with other by-products of oxidation.
The following reactions were run in a roc~ing auto-clavè under pressure tl45 psi of 20% 2 in N2) using sulfuric acid (0.11 gms) as the catalyst, acetic anhydride (11.4 ml) amd benzylidene diacetate (4 gms) in benzene (50 ml) for the time indicated at the temperature shown in the table.
The analyses were carried out by gas chromatography.
~149~15 TABLE I
% CH2(OAc)2 PhOAc In In - Reaction Reaction Conversion Reaction Reaction ~xample Time,Hrs. Temp.,C of PHCH(OAc)2 Mixture Mixture lS 0.5 200 99 21% 25%
16 1.0 200 99 22% 23%
17 1.0 170 78 8% 8%
The phenyl acetate and methylene diacetate may be recovered and separated by routine methods, as for example by distillation.
-18_ , ~ , . . ~ . ... . .. .. .
The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time, the product was worked up in accordance with the procedures of Example 1. The ratio of moles of CO2 produced to the moles of 2 consumed was 0.10.
Standardized gas chromatographic analysis of the liquid phase showed that toluene conversion was 16%.
Product selectivities (~) based on toluene con-verted were:
phenyl acetate 50methylene diacetate 51 o-methyl phenyl acetate 4 ben2yl acetate 18 phenoxymethylene acetate 8 benzylidene diacetate 6 tars and others 14 A comparison of the CO2/O2 ratio of Example 1 with that of Examples 2 and 3 clearly demonstrates the effective-ness of MoO3 in suppressing CO2 formation.
The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene 240 m mole acetic anhydride 120 m mole ~2S4 1 m mole CrO3 0.1 g ~2 230 psi 2 60 psi The temperature was rapidly raised to 202C where it was maintained for one hour. At the end of this time, the product was wor~ed up in accordance with the procedures of Example 1. The ratio of moles of CO2 produced to the moles .. .. .
~1~9~ t.~i ' f,2 consumed was ~0.3.
Standardized gas chromatographic analysis of the liquid phase showed that toluene conversion was }1%.
Product selectivities (%) based on toluene converted were:
.
phenyl acetate 20methylene diacetate 19 o-methyl phenyl acetate 5 benzyl acetate 36 phenoxymethylene acetate 12 benzylidene diacetate 16 tars and others 11 The following ingredients were charged to a 300 ml roc~ing autoclave reactor:
toluene 240 m mole acetic anhydride 120 m mole H2SO4 1 m mole wo3 0.1 g N2 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time the product was worked up in accordance with the procedures of Example 1. The ratio of moles of C02 produced to the moles f 2 consumed was 0.25.
Standardized gas chromatigraphic analysis of the liquid phase showed that toluene conversion was 8%.
Product selectivities (%) based on toluene converted wexe:
~149~
phenyl acetate35 methylene diacetate 50 o-methyl phenyl acetate 2 ~enzyl acetate 35 phenoxymethylene acetate 3 benxyldene diacetate 4 tars and others 21 A comparison of the selectivities of Examples 2 and 3, where MoO3 was employed, with the results obtained from CrO3 and W03 in Examples 4 and 5, will reveal that MoO3 is far superior to these other metals for purposes of obtain-ing the desired phenyl acetate and methylene diacetate. In addition the MoO3 provided a smoothly catalyzed reaction with little burn to C02 whereas in the cases of CrO3 and W03, 2.5 to 4.0 times as much CO2 was produced.
The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene240 m mole acetic anhydride120 m mole H2S04 1 m mole K2S28 0.1 g N2 230 psi 2 60 psi The temperature was rapidly raised to 201C where it was maintained for one hour. At the end of this time, the product was worked up in accordance with the procedures of Example 1.
Standardized gas chromatographic analysis of the liquid phase showed that toluene conversion was 16~.
Product selectivities (%) based on toluene converted were:
3~ t ~l phenyl acetate54 methylene diacetate 51 o-methyl phenyl acetate4 benzyl acetate 15 phenoxymethylene acetate 6 benzylidene diacetate 6 tars and others 15 - ioo EXA~SPLE 7 The following ingredients were charged to a 300 ml rocking autoclave reactor:
toluene240 m mole acetic anhydride 120 m mole H2SO41 m mole Dry Caro's acid0.5 g N2 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for one hour. At the end of this time, the product was worked up in accordance with the procedures of Example 1.
.
Standardized gas chromotographic analysis of the liquid phase showed that toluene conversion was 18%.
Product selectivities (%) based on toluene converted were:
phenyl acetate55 methylene diacetate S4 o-methyl phenyl acetate 4 benzyl acetate 13 phenoxymethylene acetate 6 benxylidene diacetate6 tars and others - 16 loo The following ingredients were charged to a 300 ml rocking autoclave re2ctor:
`
~i ~9~ ~5 toluene160 m mole acetic acid80 m mole ~cetic anhydride120-m mole Dry Caro's Acid0.5 g N2 230 psi 2 60 psi The temperature was rapidly raised to 203C where it was maintained for 1.5 hours. At the end of this time the product was worked up in accordance with the procédures of Example 1. Toluene conversion was 8%. Product selectivities % based on toluene were:
phenyl acetate 56%
methylene diacetate 58%
benzyl acetate 9%
others 35%
Pyrolysis of methylene diacetate to paraformalde-hyde and acetic anhydride is accomplished thermally at about 500C in a known manner.
Alternatively, the catalytic pyrolysis of methylene diacetate is carried out at about 300C in the presence of a catalyst c,omposed of 5% sodium chloride mixed with silica gel dried and calcined. The methylene diacetate, dissolved in n-hexane, is passed through a passified tubular reactor packed with the catalyst at a space velocity of 900 hr 1 and a temperature of 300C. ParaformaIdehyde and acetic anhydride condense downstream and are separated routinely. Selectivi-ties exceed 93~ for acetic anhydride and 95~ for methylene diacetate.
Pyrolysis of phenyl acetate to phenol and ketene is , ,, , .. .. , .. , . . - .
9~
accomplished thermally at 625C by passing it through a well-conditioned tubular reactor. The effluent is condensed to give 84% yield of phenol and 89% yield of ketene.
The reaction may be carried out at a somewhat lower temperature in the presence of triethyl phosphate catalyst at space velocities of between 900 and 1000 hr 1. Yields in excess of 90% are obtained.
Gaseous ketene obtained from phenyl acetate pyrolysis reacts exothermically with acetic acid (distilled from the oxidation reaction product) in a scrubber reactor with sufficient heat remo~al capacity. Heat of reaction is 15 kcal/mole. The reaction is carried out in two stages at 30-40C and pressures of 50-150 mm Hg. Conversions of acetic acid a~d ketene to acetic anhydride are 90% and 98% respect-ively. Selectivity to acetic anhydride exceeds 95%.
In a further embodiment of this invention it has been found that in a manner similar to the above-described process, hydroquinone or resorcinol, and formaldehyde can be co-produced in several steps from p-xylene or m-xylene respectively. For example, p-xylene can be oxidized to p-cresyl acetate in a known manner which can be oxidized further to hydroquinone diacetate in accordance with the process of this in~ention. The oxidation of each methyl group liberates one molecule of methylene diacetate. Hydroquinone diacetate can be saponified to give hydroquinone and acetic acid.
In this context, it has been found that persulfate , , . ., - . . - - -promoters enhance the rate and selectivity of oxidation of more complex methyl aromatics such as p-cresyl acetate far more dramatically than they enhance toluene oxidation. For example, it has been found that p-cresyl acetate is oxidized very poorly at 200C in the presence of strong acid and acetic anhydride in the absence of persulfate promoters.
Bashkirov (British Patent 1,244,080) found that it was necessary to elevate the reaction temperature to 230C to achieve oxidation of p-cresyl acetate in the presence of acetic anhydride and selectivity (20%) was very low. The instant process now achieves selectivities to hydroquinone precursors of greater than 60% at temperatures no higher than 200C using persulfate promoters, and in addition will isolate methylene diacetate as a co-product in equimolar amounts. The ability to recover methylene diacetate in equimolar amounts in all of these cases is of considerable practical value since one does not lose or waste the methyl group (as CO2) but converts it to a valuable chemical product while at the same time producing the desired phenolic precursor.
The aforementioned persulfate promoter, in one form, can be obtained by admixing potassium persulfate with sodium ~isulfate.
Para-cresyl acetate, 25 ml, benzene, 25 ml, sulf~ric acid, 0.12 gram, sodium bisulfate, 0.20 gram, potassium persulfate, 0.20 gram and acetic anhydride, 6.0 ml, were charged to a rocking autoclave and then 290 pounds of a 20/80 oxygen~nitrogen mixture was admitted. The bomb was rocked ~i4'3~5 for 90 minutes at 200C, cooled, opened and the products analyzed by glpc. Parà-cresyl acetate was converted (10%) tQ
methylene diacetate (40% selectivity) hydroquinone diacetate (63%-selectivity) and other by-products of oxidation. Select-ivities were based on ~-cresyl acetate converted.
Para-cresyl acetate, 25 ml, benzene, 25 ml, sulfuric acid, 0.06 gram, sodium bisulfate, 0.10 gram, potassium persulfate, 0.10 gram and acetic anhydride 6.0 ml were charged to a rocking autoclave and then 290 pounds of a 20/80 oxygen/nitrogen mixture was admitted. The bomb was rocked for 90 minutes at 200C, cooled, opened and the products analyzed by glpc. Para-cresyl acetate was converted (6%) to methylene diacetate (33% selectivity), hydroquinone diacetate (59% selectivity) and other products.
E ~PLE 14 Meta-cresyl acetate was oxidized in the manner of Example 1 to give methylene diacetate and resorcinol diacetate together with other by-products of oxidation.
The following reactions were run in a roc~ing auto-clavè under pressure tl45 psi of 20% 2 in N2) using sulfuric acid (0.11 gms) as the catalyst, acetic anhydride (11.4 ml) amd benzylidene diacetate (4 gms) in benzene (50 ml) for the time indicated at the temperature shown in the table.
The analyses were carried out by gas chromatography.
~149~15 TABLE I
% CH2(OAc)2 PhOAc In In - Reaction Reaction Conversion Reaction Reaction ~xample Time,Hrs. Temp.,C of PHCH(OAc)2 Mixture Mixture lS 0.5 200 99 21% 25%
16 1.0 200 99 22% 23%
17 1.0 170 78 8% 8%
The phenyl acetate and methylene diacetate may be recovered and separated by routine methods, as for example by distillation.
-18_ , ~ , . . ~ . ... . .. .. .
Claims (5)
1. A process for the oxidation of an acetate selected from p-cresyl acetate to form hydroquinone and formaldehyde or paraformaldehyde and m-cresyl acetate to form resorcinol and formaldehyde or paraformaldehyde, which process comprises:
(a) oxidizing said acetate with air or oxygen in the liquid phase under elevated temperatures and pressures in the presence of a strong acid catalyst, acetic anhydride and a persulfate promoter to form, when p-cresyl acetate is reacted, hydroquinone diacetate and methylene diacetate in approximately equimolar amounts and when m-cresyl acetate is reacted, resorcinol diacetate and methylene diacetate in approximately equimolar amounts, together with acetic acid;
(b) separating and recovering 1) said hydroquinone diacetate and methylene diacetate or 2) said resorcinol diacetate and methylene diacetate;
(c) saponifying 1) said hydroquinone diacetate to recover hydroquinone and acetic acid or 2) said resorcinol diacetate to recover resorcinol and acetic acid; and (d) pyrolyzing said methylene diacetate to recover formaldehyde paraformaldehyde and acetic anhydride.
(a) oxidizing said acetate with air or oxygen in the liquid phase under elevated temperatures and pressures in the presence of a strong acid catalyst, acetic anhydride and a persulfate promoter to form, when p-cresyl acetate is reacted, hydroquinone diacetate and methylene diacetate in approximately equimolar amounts and when m-cresyl acetate is reacted, resorcinol diacetate and methylene diacetate in approximately equimolar amounts, together with acetic acid;
(b) separating and recovering 1) said hydroquinone diacetate and methylene diacetate or 2) said resorcinol diacetate and methylene diacetate;
(c) saponifying 1) said hydroquinone diacetate to recover hydroquinone and acetic acid or 2) said resorcinol diacetate to recover resorcinol and acetic acid; and (d) pyrolyzing said methylene diacetate to recover formaldehyde paraformaldehyde and acetic anhydride.
2. A process for the oxidation of p-cresyl acetate to form hydroquinone and formaldehyde or parafor-maldehyde which comprises:
(a) oxidizing p-cresyl acetate with air or oxygen in the liquid phase under elevated temperatures and pressures in the presence of a strong acid catalyst, acetic anhydride, and a persulfate promoter to form hydroquinone diacetate and methylene diacetate in approximately equimolar amounts, together with acetic acid;
(b) separating and recovering said hydroquinone diacetate and methylene diacetate:
(c) saponifying said hydroquinone diacetate to recover hydroquinone and acetic acid; and (d) pyrolyzing said methylene diacetate to recover formaldehyde or paraformaldehyde and acetic anhydride.
(a) oxidizing p-cresyl acetate with air or oxygen in the liquid phase under elevated temperatures and pressures in the presence of a strong acid catalyst, acetic anhydride, and a persulfate promoter to form hydroquinone diacetate and methylene diacetate in approximately equimolar amounts, together with acetic acid;
(b) separating and recovering said hydroquinone diacetate and methylene diacetate:
(c) saponifying said hydroquinone diacetate to recover hydroquinone and acetic acid; and (d) pyrolyzing said methylene diacetate to recover formaldehyde or paraformaldehyde and acetic anhydride.
3. The process of Claim 2 wherein the persulfate promoter is generated from a combination of potassium persulfate and sodium bisulfate.
4. A process for the oxidation of m-cresyl acetate to form resorcinol and formaldehyde or paraformaldehyde which comprises:
(a) oxidizing m-cresyl acetate with air or oxygen in the liquid phase under elevated temperatures and pressures in the presence of a strong acid catalyst, acetic anhydride, and a persulfate promoter to form resorcinol diacetate and methylene diacetate in approximately equimolar amounts, together with acetic acid;
(b) separating and recovering said resorcinol diacetate and methylene diacetate;
(c) saponifying said resorcinol diacetate to recover resorcinol and acetic acid; and (d) pyrolyzing said methylene diacetate to recover formaldehyde or paraformaldehyde and acetic anhydride.
(a) oxidizing m-cresyl acetate with air or oxygen in the liquid phase under elevated temperatures and pressures in the presence of a strong acid catalyst, acetic anhydride, and a persulfate promoter to form resorcinol diacetate and methylene diacetate in approximately equimolar amounts, together with acetic acid;
(b) separating and recovering said resorcinol diacetate and methylene diacetate;
(c) saponifying said resorcinol diacetate to recover resorcinol and acetic acid; and (d) pyrolyzing said methylene diacetate to recover formaldehyde or paraformaldehyde and acetic anhydride.
5 . The process of Claim 4 wherein the persulfate promoter is generated from a combination of potassium per-sulfate and sodium bisulfate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000406536A CA1149415A (en) | 1978-03-27 | 1982-07-02 | Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde |
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US890,180 | 1978-03-27 | ||
| US05/890,180 US4156783A (en) | 1978-03-27 | 1978-03-27 | Conversion of benzylidene diacetate to phenyl acetate and methylene diacetate |
| US94574778A | 1978-09-25 | 1978-09-25 | |
| US945,747 | 1978-09-25 | ||
| US957,273 | 1978-11-03 | ||
| US05/957,273 US4260808A (en) | 1978-11-03 | 1978-11-03 | Catalytic process for the conversion of toluene to equimolar amounts of phenol acetate and methylene diacetate |
| CA000323630A CA1146966A (en) | 1978-03-27 | 1979-03-15 | Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde |
| CA000406536A CA1149415A (en) | 1978-03-27 | 1982-07-02 | Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1149415A true CA1149415A (en) | 1983-07-05 |
Family
ID=27508137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000406536A Expired CA1149415A (en) | 1978-03-27 | 1982-07-02 | Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1149415A (en) |
-
1982
- 1982-07-02 CA CA000406536A patent/CA1149415A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| NO153555B (en) | EXTENSION FILTER DEVICE WITH BREATHING FILTER IN A HALF MASK. | |
| CA1064520A (en) | Process for the manufacture of cyclohexane-1,3-diones and 6-alkyl-3,4-dihydro-2-pyranones | |
| US3960954A (en) | Process for preparing oximes and hydroxylamines | |
| US6166263A (en) | Processes for the manufacture of acrolein | |
| CA1149415A (en) | Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde | |
| US4260808A (en) | Catalytic process for the conversion of toluene to equimolar amounts of phenol acetate and methylene diacetate | |
| US4124633A (en) | Tellurium catalyzed decomposition of peroxide intermediates resulting from the autoxidation of unsaturated aldehydes | |
| CA1146966A (en) | Catalytic process for the conversion of toluene to equimolar amounts of phenol and formaldehyde | |
| US4504672A (en) | Catalytic process for the conversion of toluene to equimolar amounts of phenyl acetate and methylene diacetate | |
| JPS5553265A (en) | Preparation of aromatic hydroperoxide | |
| US2967187A (en) | Production of anthraquinone | |
| IL23398A (en) | Preparation of 4-alkanoyl phenoxy acids by oxidation of 4-(alkanoyl)allylbenzene compounds | |
| US4225728A (en) | Catalytic process for the conversion of ethyl benzene to equimolar amounts of vinyl acetate and phenol | |
| US4227012A (en) | Oxidation of methyl benzenes in the presence of acetic acid and a dehydrating agent | |
| US4282382A (en) | Production of cyclohexylbenzene hydroperoxide | |
| US4115440A (en) | Selenium catalyzed decomposition of peroxide intermediates resulting from the autoxidation of acrolein and methacrolein | |
| US4469887A (en) | Process for the production of methacrylic acid from isobutyraldehyde | |
| CA1146585A (en) | Co-oxidation of methyl benzenes and benzaldehyde | |
| US4237310A (en) | Co-oxidation of methyl benzenes and benzaldehyde to phenolics and formaldehyde | |
| US4036861A (en) | Process for producing a 2-tertiary-alkyl substituted anthraquinone | |
| JP4450138B2 (en) | Method for producing fluoroalkylcarboxylic acid | |
| US4237309A (en) | Method for the preparation of phenolic acetates and paraformaldehyde | |
| US4250344A (en) | Cracking process for styrene | |
| JPS5835193B2 (en) | 3.4- Methylenedioxystyrene | |
| US3704251A (en) | Production of phenyl-maleic anhydride by catalytic vapor phase oxidation of biphenyl or sec-butyl benzene |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |