CA2074886A1 - Antioxidant for aqueous systems - Google Patents
Antioxidant for aqueous systemsInfo
- Publication number
- CA2074886A1 CA2074886A1 CA 2074886 CA2074886A CA2074886A1 CA 2074886 A1 CA2074886 A1 CA 2074886A1 CA 2074886 CA2074886 CA 2074886 CA 2074886 A CA2074886 A CA 2074886A CA 2074886 A1 CA2074886 A1 CA 2074886A1
- Authority
- CA
- Canada
- Prior art keywords
- fouling
- ascorbic acid
- phenol
- processed
- polybutadiene
- 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
Abstract
ABSTRACT OF THE DISCLOSURE
A method of controlling fouling in the reboiler and distillation columns employed in the production of polybutadiene is disclosed. The addition of ascorbic acid or ascorbic acid in combination with an unhindered or partially hindered phenol such as p-methoxy phenol to polybutadiene production equipment effectively controls fouling.
A method of controlling fouling in the reboiler and distillation columns employed in the production of polybutadiene is disclosed. The addition of ascorbic acid or ascorbic acid in combination with an unhindered or partially hindered phenol such as p-methoxy phenol to polybutadiene production equipment effectively controls fouling.
Description
2~7~36 ANTIOXIDANT FOR AQUEOUS SYSTEMS
FIELD OF THE INVENTION
The present invention relates to the inhibition of fouling in petroleum equipment. More particularly, the present invention 5 relates to the use oF an antioxidant to inhibit the polymerization induced fouling of process equipment used in the manufacture of polybutadiene.
.
BACKGROUND OF THE INVENTION
Fouliny can be defined as the accumulation of unwanted matter on heat transfer surfaces. This.deposition can be very costly in refinery and petroche~ical ~lants since it increases fuel usage, results in interrupted operations and production losses and increases maintenance costs.
Deposits are found in a variety of equipment: preheat exchangers, overhead condensers, furnaces, fractionating towers, reboilers, compressors and reactor beds. These deposits are complex; broadly, they can be characterized as organic and inorganic. They consist of metal oxides and sulfides, soluble organic metals, organic polymers, coke, salts and various other particulate matter. Chemical antifoulants have been developed that effectively combat fouling.
The chemical composition of organic foulants is rarely identified completely. Organic fouling is caused by insoluble polymers which sometimes are degraded to coke. The polymers are usually formed by reaction of unsaturated hydrocarbons, although any hydrocarbon can polymerize. Generally, olefins tend to polymerize more readily than aromatics, which in turn polymerize more readily than paraffins. Trace organic materials containing ato~s such as nitrogen, oxygen and sulfur also contribute to polymerization.
Polymers are generally formed by free radical chain reactions. These reactions consist of two phases, an initiation phase and a propagation phase. In the chain initiation reaction a free radical is formed. These free radicals, which have an odd electron, act as chain carriers. Duriny chain propagation, additional free radicals are formed and the hydrocarbon molecules grow larger and larger, forming the unwanted polymers which accumulate on heat transfer surfaces.
Chain reactions can be triggered in several ways, for example heat can start the chain. When a reactive molecule such as an olefin or a diolefin is heated, a free radical is produced.
Another way a chain reaction starts is when a metal ion initiates free radical formation. Oxygen and metals can accelerate the polymerization reaction.
.
~ i4~
., As polymers form, more polymers begin to adhere to the heat transfer surfaces. The heating process results in the hydrogenation of the hydrocarbon and eventually the polymer is converted to coke.
S In refineries, deposits usually contain both organic and inorganic compounds. This mak~s the identification of the exact cause of the fouling extremely difficult. Even if it were possible to precisely identify every single deposit constituent, this would not guarantee uncovering the cause of the problem.
; 1~ Assumptions are often erroneously made that if a deposit is predominantly a certain compound, that compound is the cause of the fouling. In reality, a minor constituent in the deposit could be acting as a binder, a catalyst, or in some role that influences actual deposit formation.
The final form of the deposit as viewed by analytical . chemists may not always indicate its origin or cause. Before opening, equipment is steamed, water washed or otherwise readied for inspection. During this preparation, fouling matter can be changed both physically and chemically. For example, water solubie salts can be washed away or certain deposit constituents oxidized to another form.
In petrochemical plants, fouling matter is often organic.
Fouling can be severe where monomers convert to polymers be~ore they leave the plant. This can occur in streams high in ethylene, 2 ~
propylene, butadiene? styrene and other unsaturates. Probable locations for such reactions include units where the unsaturates are being handled or purified, or in streams which contain the reactive materials as contaminants. Even though some petro-chemical fouling problems seem similar, subtle differences in feedstock, processing schemes, equipment and contaminants can lead to variations in fouling severity. For example, ethylene plant depropanizer reboilers experience fouling that appears to be primarily polybutadiene in nature. The severity of this proble~
varies significantly from plant to plant, however, average reboiler run lengths may vary from one to two weeks up to four to six months (without chemical treatment).
Although it is usually impractical to identify the fouling problem by analytical techniques alone, this information, along with the knowledge of the process, processing conditions and the factors that contribute to fouling, are all essential to understanding the problem.
There are many ways, mechanical as well as chemical, to ~ reduce fouling. Chemical additives offer an effective means;
i 20 however, processing changes, mechanical modifications to equipment and other methods available to the plant should not be overlooked.
Antifoulants are formulated from several materials; some prevent foulants from forming, others inhibit foulant deposits on heat transfer equip~ent. Materials that inhibit deposits include antioxidants, metal coordinators and corros1On inhibltors.
2 0 ~
~5--Compounds that inhibit deposition are surfactants which act as detergents or dispersan~s. Different combinations of these properties,are blended to provide maxinlum results for different applications. These "polyfunctional" antifoulants are generally more versatile and effective since they are designed to combat various types of foulin~ that can be present in any given system.
Research indicates that even very small a~ounts of oxygen can cause or accelerate polymerization. Accordingly, antioxidant type antifoulants have been developed to prevent oxygen from initiating polymerization. Antioxidants act as chain stoppers by forming inert molecules with the oxidized free radical hydrocarbons.
Surface modifiers or detergents change metal surface characteristlcs to prevent fou1ants from depositing. Dispersants or stabilizers prevent insoluble polymers, coke and other particulate matter from agglomerating into large particles which can settle out of the process stream and adhere to metal surfaces of process equipment. They also modify the particle surface so that polymerization cannot readily take place.
Antifoulants are designed to prevent equipment surfaces from fouling. They are not designed for cleanup therefore, an antifoulant should be started immediately after equipment is cleaned. It is usually good to pretreat the system at double the recommended dosages for two to three weeks to reduce the initial hig~ rate of fouling immediately after startup.
2 ~ 7 ~
There are many areas in the hydrocarbon processing industry where antifoulants have been used successfully. In refinery crude units antifoulants have been employed at the exchangers; downstream and upstream of the clesalter, on the product side of the preheat train, on both sides oF the desalter makeup water exchanger and at the sour water stripper.
Hydrodesulfurization units of all types experience preheat fouling problems. Among those that have been successfully treated are reformer pretreaters processing bot~ straight run and coker ~; 10 naptha, desulfurizers processing catalytically cracked and coker gas oils, and distillate hydrotreaters. In one case, fouling of a unifier stripper oolumn was solved by applying a corrosion inhibitor upstream of the problem source.
.
Unsaturated and saturated gas pl2nts ~refinery vapor recovery units) experience fouling in the various fractionation columns, reboilers, and compressors. In some cases, a corrosion control program along with the antifoulant program gives the best results. In other cases, antifoulants alone are enough to solve the problem. Catalytic cracker preheat exchanger fouling, both at the vacuum column and at the cat cracker itself, has also been corrected by the use of antifoulants.
In petrochemical plants, the two most prevalant areas for fouling problems are ethylene and styrene plants. In an ethylene plant, the furnace gas compressors, the various ~ractionating 2 ~
columns and reboilers are subject to fouling. Polyfunctional antifoulants, for the most part, have provided good results in these areas. Fouling can also be a problem at the butadiene extraction area. In the different designs of butadiene plants, absorption oil fouling and distillation column and reboiler fouling have been treated with various types of antifoulants.
Fouling in ~he units used for the production of polybuta-diene rubbers from butadiene is also well known. Polybutadiene rubbers are solution polymerized polymers which are generally used in blends with styrene butadiene (SBR). Most commercial processes employ solution polymerization based upon organic lithium compounds or coordination catalysts containing metals in reduced valence states. Polymerization is carried out using dry ~onomer and salts such as aromatic, aliphatic and alicyclic hydrocarbons. Butadiene is initially washed with water and caustic to remove transport stabilizers. The washed, unstabil ked butadiene goes through a drying column and then to a reactor. Polymerization is carried out continuously in a series of large reaction vessels. The catalyst system is introduced into the monomer - solvent premix. After polymerization is complete, the viscous material is simultaneously deactivated-and stabilized with antioxidants and then washed with water to remove catalytic residues. Solvent and unreacted monomer are steam distilled (steam stripped). Popcorn polymer can form in the steam distillation towers and on the trays. It can also be present in the initial washing sections aFter the butadiene stabilizer is washed out of the monomer, just prior to reaction.
.
2 ~
Antioxidants, oxygen scavengers, metal deactivators, and dispersants are often fed to prevent and clean polymer fouling ~rom the systems process units.
The present invention is directed to antioxidant compositions and their use in con~rolling fouling which generally occurs in the reboiler and distillation columns employed in the production of polybutadiene.
' . , .
~ DETAILED DESCRIPTION ~F THE INVENTION
: .
The present invention relates to the use of specific ;~ 10 antioxidants in the reboiler and distillation columns employed in the production of polybutadiene to inhibit fouling. The specific antioxidants of the present invention include ascorbic acid and a mixture of ascorbic acid and a phenol, preferably an unhindered or - partially hindered phenol, most prefera~ly p methoxyphenol.
- 15 Unhindered phenols having electron donating groups such as an alkyl or alkoxy group (OX) where the alkyl (X) contains from 1 to 10 carbon atoms, a~ine groups (-NH2) or an alkyl substituted amine, in the para position are preferred.
, 2 ~ 3 g_ The phenols utilized are those that have the structural formula OH
R~ " R
.
where R and Rl are selected from the group consisting of hydrogen and carbon groupings (1 to 8 carbon atoms~ with the proviso that not more than 1 o$ R and Rl be secondary or tertiary carbon groupings, and R2 is alkyl, alkoxy or an amine group.
Specific exampl~s of the phenols include, but are not limited to, p creosol, p-methoxyphenol, p-amino-phenyl, p-(p-methoxy-benzylideneamino) phenol, and 2-tert-butyl-4-methoxy-phenol (butylated hyd~oxyanisole).
.~
The treatment range for the composition i.e., the ascorbic I5 acid/phenol9 clearly will be dependent upon the severity of the fouling problem due to free radical polymerization en~ountered as w~ll as the activity and constituency of the combination utilized.
For this reason, the success of the treatment is depencient upon the use of a sufficient amount for the purpose of whatever the compo-sition of c~oice is. Broadly speaking, the treatment recommenda-tion could be in the range of from 1 to 2000 parts per million being applicable and 25 ppm to 500 ppm being preferred in most cases.
.
, 2~ 3~, The following examples are presented for the purpose of illustration onl~y and should not be construed as restricting the scope of the present invention.
EXAMPLES
.
A modified version of the ASTM test method D-525 was - carried out. The modification consisted of using 100 pounds per square inch gauge of air in place of the 100 pounds per square inch gauge oxygen at 212F (100C) called for in the standard. The test was run for 19 hours with aqueous polybutadiene samples.
50 milliliters of the "aged" test fluid was then transferred to a beaker. ASTM D-381 conditions were employed to evaporate the fluid and the residue was cooled in a desicator for one hour. The weight of the residue (in mg/100 ml) was reported. The aqueous polybutadiene samples were obtained from an operating petrochemical plant. Table I summarizes data from Sampl~ 1 while Ta~le 2 summarizes data from Sample 2. The only difference between Sample 1 and Sample 2 was the date of collection and the lag time between collection and testing. The composition of the samples was:
16% isopropyl alcohol, 82% water, 0.36% acetone, 0.25% vinyl cyclohexene, 0.36% Na sulfite, 0.22% unidentified materials plus traces of polybutadiene.
Tables 1 and 2 summarize the results of the testing.
2 ~ .3 ~:!
-Il-Table 1 Sample Run Dosage tActive) _olYmer m~/lOOml Untreated --- 108.0 p-methoxyphenol 500 44.0 Ascorbic Acid 500 69.0 Ethanolamine 500 95.0 p-methoxyphenol 375/125 28.0 Ascorbic Acid p-methoxyphenol 125/375 10.0 Ascorbic Acid p-methoxyphenol 300 29.0 Ascorbic Acid 100 Ethanolamine 100 p-methoxyphenol 100 29.0 Ascorbic Acid . 300 Ethanolamine 100 Table 2 Sample_Run Dosaqe (Active) PolYmer mqL100ml Untreated --- 44.0 di~thylhydroxylamine 500 23.0 Hydroxylamine Sulfate 500 171.0 Tert-butylcatechol SOO 27.0 Oitric Acid 500 134.0 p-methoxyphenol 250/250 0.0 Ascorbic Acid Citric Acid 250/250 34.0 Ascorbic Acid -12- ~ ~ 7~
While the invention has been described with respect to particular embod;ments thereof, it is apparent that numerous other forms and modificat;ons of this invention w;ll be obv;ous to those skilled in the art. The appended claims and this ;nvention ~ 5 generally should be construed to cover all such obvious forms and :~ modifications which are within the true spirit and scope of the . . present invention.
. " . ' -
FIELD OF THE INVENTION
The present invention relates to the inhibition of fouling in petroleum equipment. More particularly, the present invention 5 relates to the use oF an antioxidant to inhibit the polymerization induced fouling of process equipment used in the manufacture of polybutadiene.
.
BACKGROUND OF THE INVENTION
Fouliny can be defined as the accumulation of unwanted matter on heat transfer surfaces. This.deposition can be very costly in refinery and petroche~ical ~lants since it increases fuel usage, results in interrupted operations and production losses and increases maintenance costs.
Deposits are found in a variety of equipment: preheat exchangers, overhead condensers, furnaces, fractionating towers, reboilers, compressors and reactor beds. These deposits are complex; broadly, they can be characterized as organic and inorganic. They consist of metal oxides and sulfides, soluble organic metals, organic polymers, coke, salts and various other particulate matter. Chemical antifoulants have been developed that effectively combat fouling.
The chemical composition of organic foulants is rarely identified completely. Organic fouling is caused by insoluble polymers which sometimes are degraded to coke. The polymers are usually formed by reaction of unsaturated hydrocarbons, although any hydrocarbon can polymerize. Generally, olefins tend to polymerize more readily than aromatics, which in turn polymerize more readily than paraffins. Trace organic materials containing ato~s such as nitrogen, oxygen and sulfur also contribute to polymerization.
Polymers are generally formed by free radical chain reactions. These reactions consist of two phases, an initiation phase and a propagation phase. In the chain initiation reaction a free radical is formed. These free radicals, which have an odd electron, act as chain carriers. Duriny chain propagation, additional free radicals are formed and the hydrocarbon molecules grow larger and larger, forming the unwanted polymers which accumulate on heat transfer surfaces.
Chain reactions can be triggered in several ways, for example heat can start the chain. When a reactive molecule such as an olefin or a diolefin is heated, a free radical is produced.
Another way a chain reaction starts is when a metal ion initiates free radical formation. Oxygen and metals can accelerate the polymerization reaction.
.
~ i4~
., As polymers form, more polymers begin to adhere to the heat transfer surfaces. The heating process results in the hydrogenation of the hydrocarbon and eventually the polymer is converted to coke.
S In refineries, deposits usually contain both organic and inorganic compounds. This mak~s the identification of the exact cause of the fouling extremely difficult. Even if it were possible to precisely identify every single deposit constituent, this would not guarantee uncovering the cause of the problem.
; 1~ Assumptions are often erroneously made that if a deposit is predominantly a certain compound, that compound is the cause of the fouling. In reality, a minor constituent in the deposit could be acting as a binder, a catalyst, or in some role that influences actual deposit formation.
The final form of the deposit as viewed by analytical . chemists may not always indicate its origin or cause. Before opening, equipment is steamed, water washed or otherwise readied for inspection. During this preparation, fouling matter can be changed both physically and chemically. For example, water solubie salts can be washed away or certain deposit constituents oxidized to another form.
In petrochemical plants, fouling matter is often organic.
Fouling can be severe where monomers convert to polymers be~ore they leave the plant. This can occur in streams high in ethylene, 2 ~
propylene, butadiene? styrene and other unsaturates. Probable locations for such reactions include units where the unsaturates are being handled or purified, or in streams which contain the reactive materials as contaminants. Even though some petro-chemical fouling problems seem similar, subtle differences in feedstock, processing schemes, equipment and contaminants can lead to variations in fouling severity. For example, ethylene plant depropanizer reboilers experience fouling that appears to be primarily polybutadiene in nature. The severity of this proble~
varies significantly from plant to plant, however, average reboiler run lengths may vary from one to two weeks up to four to six months (without chemical treatment).
Although it is usually impractical to identify the fouling problem by analytical techniques alone, this information, along with the knowledge of the process, processing conditions and the factors that contribute to fouling, are all essential to understanding the problem.
There are many ways, mechanical as well as chemical, to ~ reduce fouling. Chemical additives offer an effective means;
i 20 however, processing changes, mechanical modifications to equipment and other methods available to the plant should not be overlooked.
Antifoulants are formulated from several materials; some prevent foulants from forming, others inhibit foulant deposits on heat transfer equip~ent. Materials that inhibit deposits include antioxidants, metal coordinators and corros1On inhibltors.
2 0 ~
~5--Compounds that inhibit deposition are surfactants which act as detergents or dispersan~s. Different combinations of these properties,are blended to provide maxinlum results for different applications. These "polyfunctional" antifoulants are generally more versatile and effective since they are designed to combat various types of foulin~ that can be present in any given system.
Research indicates that even very small a~ounts of oxygen can cause or accelerate polymerization. Accordingly, antioxidant type antifoulants have been developed to prevent oxygen from initiating polymerization. Antioxidants act as chain stoppers by forming inert molecules with the oxidized free radical hydrocarbons.
Surface modifiers or detergents change metal surface characteristlcs to prevent fou1ants from depositing. Dispersants or stabilizers prevent insoluble polymers, coke and other particulate matter from agglomerating into large particles which can settle out of the process stream and adhere to metal surfaces of process equipment. They also modify the particle surface so that polymerization cannot readily take place.
Antifoulants are designed to prevent equipment surfaces from fouling. They are not designed for cleanup therefore, an antifoulant should be started immediately after equipment is cleaned. It is usually good to pretreat the system at double the recommended dosages for two to three weeks to reduce the initial hig~ rate of fouling immediately after startup.
2 ~ 7 ~
There are many areas in the hydrocarbon processing industry where antifoulants have been used successfully. In refinery crude units antifoulants have been employed at the exchangers; downstream and upstream of the clesalter, on the product side of the preheat train, on both sides oF the desalter makeup water exchanger and at the sour water stripper.
Hydrodesulfurization units of all types experience preheat fouling problems. Among those that have been successfully treated are reformer pretreaters processing bot~ straight run and coker ~; 10 naptha, desulfurizers processing catalytically cracked and coker gas oils, and distillate hydrotreaters. In one case, fouling of a unifier stripper oolumn was solved by applying a corrosion inhibitor upstream of the problem source.
.
Unsaturated and saturated gas pl2nts ~refinery vapor recovery units) experience fouling in the various fractionation columns, reboilers, and compressors. In some cases, a corrosion control program along with the antifoulant program gives the best results. In other cases, antifoulants alone are enough to solve the problem. Catalytic cracker preheat exchanger fouling, both at the vacuum column and at the cat cracker itself, has also been corrected by the use of antifoulants.
In petrochemical plants, the two most prevalant areas for fouling problems are ethylene and styrene plants. In an ethylene plant, the furnace gas compressors, the various ~ractionating 2 ~
columns and reboilers are subject to fouling. Polyfunctional antifoulants, for the most part, have provided good results in these areas. Fouling can also be a problem at the butadiene extraction area. In the different designs of butadiene plants, absorption oil fouling and distillation column and reboiler fouling have been treated with various types of antifoulants.
Fouling in ~he units used for the production of polybuta-diene rubbers from butadiene is also well known. Polybutadiene rubbers are solution polymerized polymers which are generally used in blends with styrene butadiene (SBR). Most commercial processes employ solution polymerization based upon organic lithium compounds or coordination catalysts containing metals in reduced valence states. Polymerization is carried out using dry ~onomer and salts such as aromatic, aliphatic and alicyclic hydrocarbons. Butadiene is initially washed with water and caustic to remove transport stabilizers. The washed, unstabil ked butadiene goes through a drying column and then to a reactor. Polymerization is carried out continuously in a series of large reaction vessels. The catalyst system is introduced into the monomer - solvent premix. After polymerization is complete, the viscous material is simultaneously deactivated-and stabilized with antioxidants and then washed with water to remove catalytic residues. Solvent and unreacted monomer are steam distilled (steam stripped). Popcorn polymer can form in the steam distillation towers and on the trays. It can also be present in the initial washing sections aFter the butadiene stabilizer is washed out of the monomer, just prior to reaction.
.
2 ~
Antioxidants, oxygen scavengers, metal deactivators, and dispersants are often fed to prevent and clean polymer fouling ~rom the systems process units.
The present invention is directed to antioxidant compositions and their use in con~rolling fouling which generally occurs in the reboiler and distillation columns employed in the production of polybutadiene.
' . , .
~ DETAILED DESCRIPTION ~F THE INVENTION
: .
The present invention relates to the use of specific ;~ 10 antioxidants in the reboiler and distillation columns employed in the production of polybutadiene to inhibit fouling. The specific antioxidants of the present invention include ascorbic acid and a mixture of ascorbic acid and a phenol, preferably an unhindered or - partially hindered phenol, most prefera~ly p methoxyphenol.
- 15 Unhindered phenols having electron donating groups such as an alkyl or alkoxy group (OX) where the alkyl (X) contains from 1 to 10 carbon atoms, a~ine groups (-NH2) or an alkyl substituted amine, in the para position are preferred.
, 2 ~ 3 g_ The phenols utilized are those that have the structural formula OH
R~ " R
.
where R and Rl are selected from the group consisting of hydrogen and carbon groupings (1 to 8 carbon atoms~ with the proviso that not more than 1 o$ R and Rl be secondary or tertiary carbon groupings, and R2 is alkyl, alkoxy or an amine group.
Specific exampl~s of the phenols include, but are not limited to, p creosol, p-methoxyphenol, p-amino-phenyl, p-(p-methoxy-benzylideneamino) phenol, and 2-tert-butyl-4-methoxy-phenol (butylated hyd~oxyanisole).
.~
The treatment range for the composition i.e., the ascorbic I5 acid/phenol9 clearly will be dependent upon the severity of the fouling problem due to free radical polymerization en~ountered as w~ll as the activity and constituency of the combination utilized.
For this reason, the success of the treatment is depencient upon the use of a sufficient amount for the purpose of whatever the compo-sition of c~oice is. Broadly speaking, the treatment recommenda-tion could be in the range of from 1 to 2000 parts per million being applicable and 25 ppm to 500 ppm being preferred in most cases.
.
, 2~ 3~, The following examples are presented for the purpose of illustration onl~y and should not be construed as restricting the scope of the present invention.
EXAMPLES
.
A modified version of the ASTM test method D-525 was - carried out. The modification consisted of using 100 pounds per square inch gauge of air in place of the 100 pounds per square inch gauge oxygen at 212F (100C) called for in the standard. The test was run for 19 hours with aqueous polybutadiene samples.
50 milliliters of the "aged" test fluid was then transferred to a beaker. ASTM D-381 conditions were employed to evaporate the fluid and the residue was cooled in a desicator for one hour. The weight of the residue (in mg/100 ml) was reported. The aqueous polybutadiene samples were obtained from an operating petrochemical plant. Table I summarizes data from Sampl~ 1 while Ta~le 2 summarizes data from Sample 2. The only difference between Sample 1 and Sample 2 was the date of collection and the lag time between collection and testing. The composition of the samples was:
16% isopropyl alcohol, 82% water, 0.36% acetone, 0.25% vinyl cyclohexene, 0.36% Na sulfite, 0.22% unidentified materials plus traces of polybutadiene.
Tables 1 and 2 summarize the results of the testing.
2 ~ .3 ~:!
-Il-Table 1 Sample Run Dosage tActive) _olYmer m~/lOOml Untreated --- 108.0 p-methoxyphenol 500 44.0 Ascorbic Acid 500 69.0 Ethanolamine 500 95.0 p-methoxyphenol 375/125 28.0 Ascorbic Acid p-methoxyphenol 125/375 10.0 Ascorbic Acid p-methoxyphenol 300 29.0 Ascorbic Acid 100 Ethanolamine 100 p-methoxyphenol 100 29.0 Ascorbic Acid . 300 Ethanolamine 100 Table 2 Sample_Run Dosaqe (Active) PolYmer mqL100ml Untreated --- 44.0 di~thylhydroxylamine 500 23.0 Hydroxylamine Sulfate 500 171.0 Tert-butylcatechol SOO 27.0 Oitric Acid 500 134.0 p-methoxyphenol 250/250 0.0 Ascorbic Acid Citric Acid 250/250 34.0 Ascorbic Acid -12- ~ ~ 7~
While the invention has been described with respect to particular embod;ments thereof, it is apparent that numerous other forms and modificat;ons of this invention w;ll be obv;ous to those skilled in the art. The appended claims and this ;nvention ~ 5 generally should be construed to cover all such obvious forms and :~ modifications which are within the true spirit and scope of the . . present invention.
. " . ' -
Claims (6)
1. A method of controlling fouling during the production of polybutadiene which.comprsses adding to the material being processed a sufficient amount for the purpose of an antioxidant composition comprising:
(a) an unhindered or partially hindered phenol which possesses the following formula wherein R and R1 are selected from the group consisting of hydrogen and carbon groupings with the proviso that not more than 1 of R and R1 be a secondary or tertiary carbon grouping and R2 is allyl, alkoxy or an amine group; and (b) ascorbic acid.
(a) an unhindered or partially hindered phenol which possesses the following formula wherein R and R1 are selected from the group consisting of hydrogen and carbon groupings with the proviso that not more than 1 of R and R1 be a secondary or tertiary carbon grouping and R2 is allyl, alkoxy or an amine group; and (b) ascorbic acid.
2. The method of claim 1 where the composition is added to said system in an amount of from about 1 to about 2000 parts per million of the material being processed.
3. The method of claim 2 wherein the phenol is selected from the group consisting of butylated hydroxyanisal, p-creosol, p-methoxyphenol, p-aminophenol, and p-(p-methoxybenylideneamino)phenol.
4. The method of claim 1 wherein the phenol and ascorbic acid are present in a weight ratio of from about 2 to 98 to about 98 to 2.
5. A method of controlling the fouling during the production of polybutyldiamine which comprises adding to the material being processed a sufficient amount for the purpose of ascorbic acid.
6. The method of claim 5 wherein said ascorbic acid is added to said system in an amount of from about 1 to about 2000 parts per million of the material being processed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77127991A | 1991-10-03 | 1991-10-03 | |
| US07/771,279 | 1991-10-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2074886A1 true CA2074886A1 (en) | 1993-04-04 |
Family
ID=25091300
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2074886 Abandoned CA2074886A1 (en) | 1991-10-03 | 1992-07-29 | Antioxidant for aqueous systems |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2074886A1 (en) |
-
1992
- 1992-07-29 CA CA 2074886 patent/CA2074886A1/en not_active Abandoned
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5282957A (en) | Methods for inhibiting polymerization of hydrocarbons utilizing a hydroxyalkylhydroxylamine | |
| US4927519A (en) | Method for controlling fouling deposit formation in a liquid hydrocarbonaceous medium using multifunctional antifoulant compositions | |
| CA2567894C (en) | Method of dispersing hydrocarbon foulants in hydrocarbon processing fluids | |
| US4927561A (en) | Multifunctional antifoulant compositions | |
| US3776835A (en) | Fouling rate reduction in hydrocarbon streams | |
| US4775458A (en) | Multifunctional antifoulant compositions and methods of use thereof | |
| JPS63502192A (en) | Method for suppressing deposits on hydrocarbon compositions containing olefin compounds | |
| CN101037618A (en) | Coking inhibitor and preparation method and application thereof | |
| KR20090074153A (en) | Method of removal of calcium from hydrocarbon feedstock | |
| US4889614A (en) | Methods for retarding coke formation during pyrolytic hydrocarbon processing | |
| US20230151283A1 (en) | Hydrocarbon pyrolysis of feeds containing nitrogen | |
| US5770041A (en) | Non-enolizable oxygenates as antifoulants | |
| US5221461A (en) | Antioxidant compositions and methods using catechol compounds and organic acid compounds | |
| US3328284A (en) | Oxyalkylate-sulfonate hydrocarbon inhibitor | |
| US4810354A (en) | Bifunctional antifoulant compositions and methods | |
| DE60221990T2 (en) | Multi-stage method for removing sulfur from fuel components for use in vehicles | |
| US5154817A (en) | Method for inhibiting gum and sediment formation in liquid hydrocarbon mediums | |
| CA3209451A1 (en) | Stabilizer additives for plastic-derived synthetic feedstock | |
| US5221498A (en) | Methods and compositions for inhibitoring polymerization of vinyl monomers | |
| US4941968A (en) | Method for inhibiting gum formation in liquid hydrocarbon mediums | |
| JPS6153392A (en) | Improvement in operation of oil factory and petrochemical plant | |
| US5128022A (en) | Antioxidant compositions and methods using p-phenylenediamine compounds and organic acid compounds | |
| US5158667A (en) | Methods for inhibiting fouling in fluid catalytic cracking units | |
| CA2074886A1 (en) | Antioxidant for aqueous systems | |
| US5271824A (en) | Methods for controlling fouling deposit formation in a liquid hydrocarbonaceous medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |