KR100759746B1 - Process for making butenyl esters from butadiene - Google Patents

Abstract

A process for preparing butenyl esters from butadiene by reacting a hydrocarbon moiety or butadiene comprising butadiene with a saturated aliphatic monocarboxylic acid, wherein the catalyst is a rhenium (VII) oxide or at least two sulfonic acid groups per molecule. Organic sulfonic acids, wherein the ratio of carbon atoms to sulfonic acid groups in the organic sulfonic acid ranges from 1: 1 to 1: 0.15. Preferred catalysts are organic disulfonic acids, for example ethane-1,2-disulfonic acid. The process can be used for preparing unsaturated esters or for the production of saturated esters such as, for example, butyl acetate by hydrogenation of the product. The catalyst can be purified and recycled to the reactor.

Butadiene, butyl ester, 1,2-disulfonic acid, hydrogenated, rhenium (VII) oxide, organic sulfonic acid

Description

Production method of butenyl ester from butadiene {PROCESS FOR MAKING BUTENYL ESTERS FROM BUTADIENE}

Process for preparing esters from butadiene

The present invention relates to a process for preparing esters which react butadiene with carboxylic acids in the presence of a Brentstead or Lewis acid catalyst to form unsaturated esters.

It is known that esters such as n-butyl acetate can be produced via many routes. For example, hydroformylation of propylene in the presence of acetic acid is a method of producing a mixture of n-butyl acetate and iso-butyl acetate. An alternative method is to react ethylene with vinyl acetate in the presence of an acid catalyst and then hydrogenate the resulting unsaturated ester. Another method is the reaction of ethylene with ethanol to form butanol in the presence of a base catalyst, and its acetic acid to form butyl acetate. Acid-catalyzed addition of butadiene to acetic acid using ion-exchange resin catalysts with bulk counterions to improve reaction selectivity for two isomerized C ₄ butenyl acetates has been described in several patents, namely US-A- 4,450,288 (alkyl pyridinium), US-A-4,450,287 (quaternary ammonium), US-A-4,450,289 (quaternary phosphonium). Butadiene is a relatively inexpensive byproduct of the purification process and a potential feedstock for the production of butyl esters. It is commercially available as a component of the purified chemical or hydrocarbon cut, for example as a component of mixed C ₄ streams obtained from naphtha stream cracking. Typically such streams include varieties such as butane, 1-butene, 2-butene, isobutane and isobutene in addition to butadiene. It is an advantage that the method using butadiene can utilize this stream. However, butadiene is also in equilibrium with 4-vinyl cyclohexene, the Diels Alder dimer of butadiene. This dimer can be thermally cracked to become butadiene again:

As such, any method involving the use of butadiene as feedstock needs to account for this reversible reaction.

EP-A-84133 describes methods for producing unsaturated alcohols and / or esters of unsaturated alcohols. This reference describes the reaction between the conjugated diene and water or aqueous carboxylic acid. The resulting product is a complex mixture of unsaturated isomerized alcohols and esters.

US-A-4405808 discloses a process for preparing acetic acid esters by reacting acetic acid with aliphatic lower olefins in the vapor phase in the presence of water vapor in a catalyst selected from the group consisting of aromatic disulfonic acids and esters thereof. There is no disclosure using dienes in place of aliphatic lower olefins. Specific examples of US-A-4405808 relate only to the production of ethyl acetate and isopropyl acetate.

Applicant's WO 00/26175 from the butadiene, comprising the formation of a mixture of n-butenyl and secondary butenyl esters by reaction of a hydrocarbon moiety comprising butadiene or butadiene with a saturated aliphatic monocarboxylic acid as a first step Disclosed is a process for preparing butyl esters.

The process is said to be suitable for catalysis by heterogeneous or homogeneous catalysts. Suitable homogeneous catalysts are said to include monosulfonic acid, tricyclic (trifluoromethanesulfonic acid) and salts (triplates) thereof. Suitable organic sulfonic acids disclosed are methane sulfonic acid, p-toluene sulfonic acid and sulfonated calyx arene.

The inventors have found that the process can be performed with an improved combination of selectivity and yield using certain specific catalysts.

Accordingly, the present invention provides a process for preparing butyl esters from butadiene, the process comprising reacting a hydrocarbon moiety or butadiene comprising butadiene with a saturated aliphatic monocarboxylic acid, wherein the catalyst is rhenium (VII) Organic sulfonic acids comprising at least two sulfonic acid groups per oxide or molecule, wherein the ratio of carbon atoms to sulfonic acid groups in organic sulfonic acids ranges from 1: 1 to 1: 0.15.

In the sulfonic acid catalyst used in the process of the invention, the ratio of the number of carbon atoms to sulfonic acid groups is preferably in the range of 1: 1 to 1: 0.2, more preferably in the range of 1: 1 to 1: 0.5 and most preferably In the range from 1: 1 to 1: 0.7. The sulfonic acid preferably contains 2 to 30 carbon atoms, more preferably 2 to 10 carbon atoms and most preferably 2 to 8 carbon atoms.

The concentration of the defined sulfonic acid or rhenium oxide catalyst used in the liquid phase of the reaction mixture can be kept constant throughout the reaction, or can vary or still be within a wide range of concentrations, while still achieving the desired result.

The reaction can be carried out under batch conditions, for example, using a single aliquot of a rhenium oxide catalyst or a defined sulfonic acid catalyst dissolved in some or all of the carboxylic acid, while gradually pumping butadiene gas into the reaction. . Under these conditions, the concentration of the catalyst generally decreases due to the dilution effect as more butadiene forms liquid esters and enters the liquid phase. Alternatively, the reaction may be carried out by continuously or intermittently feeding butadiene and / or catalyst and / or carboxylic acid to maintain the concentration of catalyst and reactants at a desired level. The catalyst can be supplied as a solid or a liquid. The catalyst supplied to the reactor can be dissolved in one of the solvents or reactants if desired, for example the catalyst can be dissolved in additional carboxylic acid if desired.

Preferably the catalyst concentration comprises 0.2 to 10% by weight, preferably at least 0.5 to 7% by weight and most preferably 1 to 5% by weight of sulfonic acid catalyst or rhenium oxide catalyst, based on the weight of the total reaction mixture. maintain. The sulfonic acid catalyst or rhenium oxide catalyst of the present invention is preferably soluble in the reaction mixture.

delete

Although the reaction mixture preferably forms a single liquid phase, the reaction mixture may comprise two or more phases if desired.

Examples of suitable sulfonic acid catalysts include 1,2-ethane disulfonic acid, benzene-1,2-disulfonic acid, benzene-1,3-disulfonic acid, benzene-1,4-disulfonic acid, naphthalene-1,5-disulfonic acid, Naphthalene-2,6-disulfonic acid, naphthalene-2,7-disulfonic acid, 4-chlorobenzene-1,3-disulfonic acid, 4-fluorobenzene-1,3-disulfonic acid, 4-bromobenzene-1 , 3-disulfonic acid, 4,6-dichlorobenzene-1,3-disulfonic acid, 2,5-dichlorobenzene-1,3-disulfonic acid, 2,4,6-trichlorobenzene-1,3-disulfonic acid , 3-chloronaphthalene-2,6-disulfonic acid, benzene trisulfonic acid and naphthalene trisulfonic acid.

The defined sulfonic acid catalysts used in the present invention comprise two or more sulfonic acid groups per molecule. If the ratio of the overall average carbon to sulfonic acid catalysts defined is in the range of 1: 1 to 1: 0.15, the sulfonic acid catalysts defined above comprise a single sulfonic acid compound or a plurality of different sulfonic acid compounds, each according to the defined sulfonic acid. can do.

If desired, the sulfonic acid catalyst of the present invention as defined above may be used in admixture with one or more other catalysts known to be effective for catalyzing the addition reaction. For example, the sulfonic acid as defined above can be used in admixture with a monosulfonic acid catalyst. Preferably the sulfonic acid catalyst of the present invention forms at least 5%, more preferably at least 10%, most preferably at least 50% by weight of the total catalyst content. Particular preference is given to the use of a catalyst containing 80 to 100% by weight of the defined sulfonic acid catalyst.

Butadiene used in the present invention may be used in the form of substantially pure butadiene. Alternatively, hydrocarbon mixtures comprising butadiene may be used, for example industrial hydrocarbon gas streams comprising butadiene. In one embodiment a raw (eg crude or depleted) C ₄ stream is used, in particular containing butadiene, isobutene, 1-butene, 2-butene and butane. Such streams may contain up to 60% butadiene.

The saturated aliphatic monocarboxylic acids used in the present invention are preferably C ₁ to C ₃₀ , more preferably C ₂ to C ₁₅ , most preferably C ₂ to C ₆ acids. Acetic acid is particularly preferred.

The reaction is preferably carried out in the presence of water. For example, the liquid phase may comprise 0.01 to 10% by weight, more preferably 0.05 to 5% by weight of water, based on the total liquid. In general, a range of 0.1 to 5.0% by weight, based on low levels of water, for example the total reaction mixture, has been found to be very beneficial for the desired reaction. Thus, at levels above 5% w / w, catalytic activity tends to decrease significantly, while at levels below 0.05% w / w it is found that higher activity but unacceptable selectivity loss may occur. lost. As a result, the water level in the reaction zone is suitably in the range of 0.05 to 5% w / w, preferably in the range of 0.05 to 1% w / w for carboxylic acids. Also at high levels of water, the hydrolysis of the product esters can be high, for example the resulting production mixture comprising allylic alcohols can incur additional costs in product workup.

The reaction is suitably carried out in a liquid or mixed phase of liquid / gas in the presence of a solvent. The reaction is preferably carried out under conditions in which the reaction between butadiene and carboxylic acid occurs in the liquid phase. If a solvent is used, it is not necessary to completely dissolve both reactants in the solvent. However, it is advantageous if the solvent chosen can dissolve both reactants properly. Specific examples of such solvents include hydrocarbons such as decane and toluene and oxidized solvents such as glim, ethers and esters such as n-butyl acetate or excess carboxylic acid reactants and recycled higher esters such as C ₈ acetate and Recycled sec-butenyl acetate. The use of excess carboxylic acid as reactant may be advantageous when the process of the present invention is used as part of a process for extracting butadiene from a crude stream, which may result in high conversion of butadiene, or from a process point of view, high efficiency of butadiene removal. This is because the reaction is facilitated. In current commercial practice, the removal or recovery of butadiene from the purified stream requires a separate treatment step.

시리즈의 물질, Great Lakes Chemical Corporation의 Lowinox

시리즈의 물질, ICI의 tropanol

시리즈 및 t-부틸카테콜, 일산화질소, 니트록시드 및 유도체들(예를 들면 디-t-부틸니트록시드, 및 n,n-디메틸-4-니트로소아닐린), 안정한 라디칼(예를 들면 2,2,6,6-테트라메틸-피페리딘-1-옥실, 2,2,6,6-테트라메틸-4-히드록시피페리딘-1-옥실 및 2,2,6,6-테트라메틸피롤리딘-1-옥실)을 포함한다. It is also advantageous in the process of the invention to use polymerization inhibitors such as alkylated phenols (eg BHT butylated hydroxytoluene, also called 2,6-di-tert-butyl-p-cresol). Other members of these series are Irganox of Ciba Gigy

Series of materials, Lowinox, Great Lakes Chemical Corporation

Substance of series, ICI tropanol

Series and t-butylcatechol, nitrogen monoxide, nitroxides and derivatives (e.g. di-t-butylnitroxide, and n, n-dimethyl-4-nitrosoaniline), stable radicals (e.g. 2,2,6,6-tetramethyl-piperidine-1-oxyl, 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl and 2,2,6,6- Tetramethylpyrrolidine-1-oxyl).

The relative molar ratio of butadiene to carboxylic acid reactant in the addition reaction is suitably in the range from 5: 1 to 1:50, preferably in the range from 1: 1 to 1:10.

The reaction is suitably carried out in a temperature range of 20 to 140 ° C, preferably 20 to 130 ° C, more preferably 30 to 120 ° C, and most preferably 40 to 90 ° C. The reaction pressure is preferably an autogenous reaction pressure determined by factors such as excess reactants and impurities present in the butadiene stream, the absence of solvent, the reaction temperature. If a single liquid phase without the butadiene gas phase is desired, for example in addition to the liquid phase, which may optionally contain a solvent, additional pressure may be applied to the system.

The stream fed to the reaction is preferably treated to remove corrosive metals and / or basic impurities such as ammonia or organic bases derived from them. Such corrosive metals or bases can be reacted with, for example, sulfonic acid catalysts to inactivate it.

Devices for carrying out this reaction will be well known to those skilled in the art. For example, the reaction may suitably be carried out in a plug flow reactor, slurry reactor or continuous stirred tank reactor. If a plug flow reactor is used, the unused butadiene is preferably flash removed and recycled to the reactor via a vapor liquid separator. In the case of a plug flow reactor, butadiene may be present in partly in a gaseous and dissolved state, which will allow operation, for example, in a trickle bed device or a bubble bed device. Butadiene feed may be added, for example, at various places in the reactor (eg spaced along the length of the plug flow reactor). In the case of a bubble bed device, the butadiene can be added in the countercurrent direction to the carboxylic acid feed, if desired. Typical liquid hourly space velocity (liquid hourly space velocity = feed liquid volume / catalyst bed volume) for carboxylic acids is 0.1-20, more preferably 0.5-5. In the case of a continuous stirred tank reactor, a plurality of reactors in series can be used if desired, and a continuous bleed of any deactivated catalyst can be taken. In this case it is economically advantageous to carry out with the catalyst in various inactivation steps in order to improve the utilization of the catalyst. This can lead to high levels of loading of the total catalyst (active + inert), for example up to 50% w / w or more of the reaction charge. If desired, new catalysts can be added continuously or intermittently if desired to maintain the desired level of active catalyst in the reactor (s).

Preferably, butadiene can be added gradually to the saturated aliphatic monocarboxylic acid, for example, by multiple injections at constant pressure in a batch reactor. By gradually adding butadiene in this way, side reactions leading to, for example, the polymerization of butadiene can be minimized.

The addition of the present invention may be followed by separation of isomerized butenyl esters, such as n-butenyl esters and secondary butenyl esters, as disclosed in the applicant's prior application WO 00/26175. The sec-butenyl ester can be recovered and recycled to the initial addition reaction between butadiene and carboxylic acid. It was found that the sec-butenyl esters were interconverted with butadiene, free carboxylic acid and crotyl esters under the reaction conditions. The conversion of the sec-butenyl ester to free carboxylic acid and butadiene can be accomplished by treatment with an acidic support such as, for example, silica alumina in the vapor phase. The use of such separate pretreatment prior to return to carboxylic acid and butadiene in the addition reactor can have a beneficial effect on productivity and selectivity.

In the case of acetic acid addition to 1,3-butadiene, the use of the defined sulfonic acid catalysts of the present invention instead of monosulfonic acid catalysts provides significant advantages in terms of activity. Improved protonation of the resulting 1,3-butadiene substrate provides a more preferred route to crotyl and sec-butenyl acetate for the sulfonic acid catalyst of the present invention, for example, as shown in the examples below. Although the increased activity in the addition reaction is marked by a loss of selectivity for the reagents, the overall productivity is much greater for the sulfonic acid catalyst system of the present invention.

The theoretical process flow diagram is illustrated in FIG. 1. The butadiene and acetic acid are fed to the liquid phase reactor in the presence of water and a catalyst. The stream is taken and mixed with cyclohexane before separation in decanter (V1). The aqueous phase is recycled to the reactor, while the cyclohexane comprising the aqueous phase is diluted with more water and sent to the second decanter (V2) where any residual catalyst is removed with the aqueous phase (previous column is contaminated). To prevent them). Column D1 flashes butadiene over the head for recycle to the reactor. A side draw is taken to return the cyclohexane to the stream from the reactor, while the stream from the column base (including water, acetic acid, crotyl acetate, sec-butenyl acetate and reaction byproducts) It is fed to column D2. This column will be operated to remove crude crotyl acetate stream from the column base, while water / acetic acid / sec-butenyl acetate is distilled over the head and returned to the reactor with butadiene and recycled. The crude crotyl acetate stream is fed through a guard bed (to remove traces of acid) and then hydrogenated. The desired butyl acetate stream can then be separated by final distillation from the remaining heavy boiler. Distillation column D3 is provided for purification of butyl acetate produced by hydrogenation of crotyl acetate. Distillation column D4 is provided for the purification of C8 acetate ester by-products, which may be of value if desired on their own or as alcohols obtained from saponification of such esters.

1A is a theoretical process flow diagram illustrating a procedure for purifying and / or concentrating a catalyst used in the present invention. Addition reactions of the present invention tend to produce progressively small amounts of non-volatile by-products and, after prolonged operation, tend to reduce the effective activity of the catalyst by dilution effects. In a preferred embodiment of the invention, the catalyst is purified continuously or intermittently with the removal of these byproducts. The purification process involves diluting a portion of the reaction mixture with water, mixing it with a solvent that is not mixed with water, extracting organics from the resulting mixture, optionally concentrating the resulting aqueous catalyst solution, and returning the catalyst solution to the reactor. do.

Thus, Figure 1A illustrates a procedure that can be applied to the recycling of the sulfonic acid catalyst to the reaction, for example in the preparation of butenyl acetate from butadiene and acetic acid. The reaction is carried out in a vessel which may be, for example, a bubble, tube, or stirred tank reactor. The discharge product stream, which consists of unconverted reactants, reaction by-products and reaction products, still contains the active catalyst, and if left to come into contact with the reaction product for a long time during the product work-up, catalyze the reverse reaction to release butadiene, reactant and loss of product Brings about. Minimizing the contact time of the desired reaction product with the catalyst under distillation conditions can reduce the degree of reverse reaction. This can be facilitated with the careful design of the distillation apparatus, in which the reactant release mixture is first separated from the volatile components in the flash tank, which produces a recycle stream of volatile components such as butadiene and vinyl cyclohexane, which is then subjected to considerable purification. . The first step of the purification may be a falling film, short path or wiped film distillation apparatus. This resulting heavy end stream contains the catalyst as a high boiling point component. It has been found that by chance that many high-boiling reaction by-products are in dynamic equilibrium with the target reaction products and starting materials, recycling many of these materials with the catalyst. Undesired impurities will accumulate in any recycle ring, which often requires the release of such materials to those skilled in the process design art. In the case of a catalyst recycle stream it has been found that this can lead to unwanted losses of expensive catalysts and that liquid extraction of this residual stream enables the recovery of the catalyst in the aqueous phase from the byproduct oil phase. This separation can be facilitated by the addition of agents which are mostly insoluble in water such as hydrocarbons such as cyclohexane.

The present invention is now described with reference to the following examples, where Example 1 shows the reaction of the invention in the production of butenyl acetate and Example 2 shows experimental details of the extraction and purification procedures of the catalyst. .

Example 1

Reaction of Butadiene with Acetic Acid

The experiment was carried out in a glass vessel adapted to the batch reaction to run near atmospheric pressure on a total reactant scale of 100 g. Several experiments using this method were conducted simultaneously to maximize reproducibility. 1,2-ethanedisulfonic acid and 1,5-naphthalenedisulfonic acid were compared with ethanesulfonic acid, monosulfonic acid. Rhenium (VII) oxide was also tested. Reagents were used as supplied from Aldrich.

Typical reaction charges:

97.9 g of acetic acid (containing about 500 ppm BHT)

0.1 g of water                 

2.0 g of catalyst

The water content of the acetic acid feed was measured using the Karl-Fischer titration method (analysis was repeated with values within 0.05% w / w) and the level was adjusted to what is required. The reaction vessel was heated to 60 ° C. through a water jacket, acetic acid (prepurged with nitrogen), water, inhibitor (BHT-2,6-di-tert-butyl-4-methylphenol or butylated hydroxy) Toluene) and catalyst were loaded in the required amounts. A magnetic stir bar was inserted and the contents allowed to equilibrate with the bath temperature. 1,3-butadiene was introduced into the reaction liquid directly from the liquid supply leach bottle through the side basin into the reaction liquid and vented through a second side branch through a gas manifold designed to allow some overpressure of butadiene. The vessel was purged with butadiene at a constant flow rate for 10 minutes. This addition point was considered t = 0 and the stirred autoclave contents were sampled at regular intervals and analyzed by flame ionization detector (FID) gas chromatography (GC). The GC peak was characterized by synthesis of the model compound and GC / MS. GC was assayed by purchasing and synthesizing pure compounds such as acetic acid, butenyl acetate, sec-butenyl acetate, and 4-vinyl cyclohexane. The higher boiling by-products from the reactions were approximately quantified by assigning the same reaction factors as measured for butenyl acetate. All these higher boiling point peaks were combined with each other-named "high boiling point substances"-the calculated% w / w was used in the calculation of the reaction selectivity.

Table 1 below shows the total C ₄ acetate (sec-butenyl and crotyl acetate) yields of the monosulfonic acid ESA (ethanesulfonic acid) catalyzed experiments, calculated by weight relative to the loading weight criteria (dissulfonic acid). It is less than half of the yield for the equivalent experiment with EDSA (1,2-ethane disulfonic acid). For ESA to EDSA the ratio of sulfonic acid groups based on the 2 g catalyst is 5: 6, which demonstrates a significant improvement in activity per sulfonic acid group in the disulfonic acid system. Further improvement in sulfonic acid group activity is also observed for 1,5-naphthalene disulfonic acid (Example 5). The effect of increasing water content on C ₄ acetate production is different in the two systems. For ESA, a slight increase in activity was observed when moving from 0.3 to 1.0% (about 11%), whereas EDSA showed a decrease in activity (14%). The idea of assisted acidity between closely adjacent acid sites will explain the decrease in activity against EDSA, which is further illustrated by Example 6. Runs 7 and 9 show similar results for the same catalyst at lower loading (a slight decrease is observed in both cases when moving from 2 to 1% w / w). Under the same conditions, rhenium (VII) oxide (Example 8) produces about 80% C ₄ acetate, which is significantly more than ESA compared to EDSA.

Comments in the table above:

ESA-ethanesulfonic acid (comparative); EDSA-1,2-ethanedisulfonic acid; RO-rhenium (VII) oxide; NDSA-1,5-naphthalenedisulfonic acid.

Table 2 below compares the selectivity of the homogeneous catalysts and associates them to their respective activities by calculation of productivity. The selectivity decreases with respect to both acetic acid and butadiene in the case of equivalent systems, moving from monosulfonic acid to disulfonic acid groups. This suggests that the aid of acidity of disulfonic acids not only improves the production of C ₄ acetate but also improves the route to by-products to a greater extent, i.e., improved acidity favors the formation of C ₈ acetate and butadiene oligomers over C ₄ acetate. Imply that. Rhenium (VII) oxide also exhibits poor selectivity than ESA. By associating selectivity and activity, productivity values can be assigned to catalysts for comparisons made to overall catalyst performance. These calculations suggest that, for a given set of reaction conditions, EDSA performs much better overall than ESA in producing C ₄ acetate. NDSA and rhenium (VII) oxides exhibit productivity close to EDSA.

Comment on the table above:

a-ESA-ethanesulfonic acid (110.13); EDSA-1, 1,2-ethanedisulfonic acid (FW 190.20); RO-rhenium (VII) oxide (FW 484.40); NDSA-1,5-naphthalenedisulfonic acid tetrahydrate (FW 360.36).

b-C ₄ selectivity (relative to butadiene) = [C ₄ acetate] / ([C ₄ acetate] + 2 [C ₈ acetate] + 2 [dimer]] + [oligomer + trimer])

c-C ₄ selectivity (relative to acetic acid) = [C ₄ acetate] / ([C ₄ acetate] + [C ₈ acetate])

d-productivity = (selectivity / 100 for butadiene) * total C ₄ acetate

As shown in Tables 3 and 4 below and FIGS. 4 and 5, similar experiments were performed comparing methanesulfonic acid (MSA) to EDSA (2% catalyst loading, 0.12% water, 60 ° C.).

In the case of previous systems, the initial production of C ₄ acetate per acid group is much higher in disulfonic acid than in monosulfonic acid, but in this system the C ₄ acetate concentration reaches equilibrium faster. Thus the final C ₄ acetate level in each system is much closer to each other than that of the initial run (FIGS. 2 and 3). Clearly, in the case of direct addition reactions, it is advantageous to use disulfonic acid catalysts for monosulfonic acid catalysts, especially at shorter reaction times (the equilibrium factor for the reaction rate is less limited).

Example 2

1. Experimental

Reagents were used as supplied by Aldrich Chemical Company without further purification. Standard "Quickfit" laboratory glass containers were used for this experiment. These experiments were performed at atmospheric pressure unless otherwise noted. The catalyst was recovered and subjected to a series of seven successive batch reactions recycled to aqueous extraction.

In the initial run, three necked round bottom flasks were equipped with 1,2-ethanedisulfonic acid (10.26 g, 2.07% w / w) and acetic acid (486.10 g, Karl-Fisher analysis, 0.84% w / w water). Containing) and mechanically stirred to aid dissolution (15 min). The flask was connected to a butadiene feed inlet (from Lecture bottle) and a glass bubbler vent outlet, and the device was placed on a tared balance. A stream of butadiene was fed to the reaction until 30-40 g dissolved in the reaction medium. The butadiene feed was then isolated and then the flask was transferred to a " Haake " bath and a bath maintained at < RTI ID = 0.0 > 60 C < / RTI > by a mechanical stirrer attached through the middle neck. The reaction is intended to begin when the stirrer is turned on. After about 18 hours a sample (about 3 g) was extracted from the reaction mixture with a syringe through a Suba seal and used for GC analysis of the reaction components. The stirrer and bath were turned off and the reaction allowed to cool.

Once cooled, the catalyst was recovered by the following liquid-liquid extraction technique. The crude mixture was diluted with water (200 g) and extracted with cyclohexane (2x200 g). The aqueous acetic acid phase was charged to a Buchner flask and concentrated to oil in a rotary evaporator (about 30 mBar, <50 ° C.) until no more volatiles were removed. The oil was dissolved in fresh acetic acid (490 g), the water level was adjusted to about 1% if necessary, and the mixture was transferred to the reaction flask for subsequent runs. At this point a sample (approximately 3 g) was taken to determine the initial composition of the fill (GC analysis). The flask was then filled with 30-40 g butadiene (as before) and the run was resumed. The process was repeated until the catalyst was used seven times.

Run 1-7

As the sampling for analysis during the above run caused a loss of the catalyst, the amount of catalyst was also measured to determine the specific activity of the catalyst.

GC analysis was performed on a Perkin-Elmer Autosystem chromatograph (column supported with 100 m silica) equipped with an automated sampling device. Decane (about 1%) was used as internal standard to obtain the composition of C ₄ acetate product and reaction byproducts (mainly C ₈ acetate and butadiene dimer / oligomer). A blank THF sample was performed after each run of the sample to confirm the elution of heavier components (eg butadiene trimers, oligomers) from the column. Results are expressed in weight percent of total composition weight, assayed against internal standards.

Cyclohexane extracts from each run were analyzed for sulfur to determine the extent of any catalyst exiting during the recycle process. The assigned value was included in the calculation for the catalyst lost during the sampling process.

Table 1- Mass Balance Data for Run 1

Technology Weight (g) Packed acetic acid (0.84% w / w) 486.10 Filled EDSA 10.26 ^a Acetic Acid + Filled Catalyst 496.36 butadiene 35.61 Reaction mixture at the end of the run 501.26 Estimated butadiene absorption ^b 12.77 Water added to the mixture 195.91 Cyclohexane Extract 1 198.52 Recovered Cyclohexane 207.77 Cyclohexane Extract 2 136.73 Recovered Cyclohexane 148.13 Residue after acetic acid / water removal 13.11 Sample removed 7.87 ^c Catalyst lost during sampling 0.16 ^d

a-catalyst concentration = 10.26 / 496.36 = 2.07% w / w

b-(mixture at end + sample taken)-(acetic acid + packed catalyst)

c-sample removed = 100 x 7.87 / 496.36 = 1.58% of total

d-lost catalyst = 1.58 x 10.26 / 100 = 0.16 g

Table 2-GC Data for Implementation 1

sample time Weight (g) Crotyl acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Conduct 1-1 One 3.99 0.057 0.099 0.156 Practice 1-2 18 3.88 1.108 1.049 2.157

Conduct 2

Table 3-Mass Balance Data for Run 1

Estimated catalyst concentration = 2.01%

Technology Weight (g) Refilled acetic acid (1.01% w / w) 490.05 Residue mass 13.11 Residue + Acetic Acid Filling 503.16 butadiene 35.20 Reaction mixture after the end of the run 501.35 Estimated Butadiene Absorption 10.32 Water added to the mixture 197.19 Cyclohexane extract 198.05 Recovered Cyclohexane 203.26 Cyclohexane Extract 2 201.61 Recovered Cyclohexane 215.63 Residue after acetic acid / water removal 16.99 Sample removed 12.13 Catalyst lost during sampling 0.24

Table 4-GC Data for Run 2

sample time Weight (g) Crotyl Acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Conduct 2-1 0 3.52 0.062 0.06 0.122 Act 2-2 16 4.77 1.045 1.003 2.048 Conduct 2-3 18 3.84 1.3 1.21 2.51

Conduct 3

Estimated catalyst concentration = 1.94%

Table 5-Mass Balance Data for Run 3

Technology Weight (g) Refilled acetic acid (1.36% w / w) 490.92 Residue 16.99 Residue + Acetic Acid Filling 507.91 butadiene 31.56 Reaction mixture at the end of the run 508.82 Estimated Butadiene Absorption 7.39 Water added to the mixture 200.53 Cyclohexane Extract 1 198.13 Recovered Cyclohexane 208.80 Cyclohexane Extract 2 198.42 Recovered Cyclohexane 209.36 Residue after acetic acid / water removal 12.33 Sample removed 6.48 Catalyst lost during sampling 0.13

Table 6- GC Data for Run 3

sample time Weight (g) Crotyl Acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Act 3-1 2 3.97 0.071 0.122 0.193 Act 3-2 18 2.51 0,87 0.851 1.721

Conduct 4

Estimated Catalyst Concentration = 1.92%

Table 7-Mass Balance Data for Run 4

Technology Weight (g) Refilled acetic acid (1.01% w / w) 495.30 Residue 12.33 Residue + acetic acid 507.63 butadiene 35.20 Reaction mixture at the end of the run 504.43 Estimated Butadiene Absorption 5.43 Water added to the mixture 200.74 Cyclohexane Extract 1 201.60 Recovered Cyclohexane 212.45 Cyclohexane Extract 2 200.48 Recovered Cyclohexane 207.84 Residue after acetic acid / water removal 32.99 Sample removed 8.63 Catalyst lost during sampling 0.17

Table 8- GC Data for Run 4

sample time Weight (g) Crotyl Acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Act 4-1 0 4.04 0.053 0.049 0.102 Act 4-2 18 4.59 0.959 0.907 1.866

Conduct 5

Estimated Catalyst Concentration = 1.82%

Table 9-Mass Balance Data for Run 5

Technology Weight (g) Refilled acetic acid (1.78% w / w) 492.62 Residue 32.99 Residue + acetic acid 525.61 butadiene 37.43 Reaction mixture at the end of the run 527.44 Estimated Butadiene Absorption 9.27 Water added to the mixture 199.97 Cyclohexane Extract 1 203.25 Recovered Cyclohexane 214.94 Cyclohexane Extract 2 200.29 Recovered Cyclohexane 213.53 Residue after acetic acid / water removal 20.66 Sample removed 7.44 Catalyst lost during sampling 0.14

Table 10- GC Data for Run 5

sample time Weight (g) Crotyl Acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Act 5-1 0 3.44 0.053 0.049 0.102 Act 5-2 18 4.00 0.53 0.585 1.115

Conduct 6

Estimated catalyst concentration = 1.84%

Table 11-Mass Balance Data for Run 6

Technology Weight (g) Refilled acetic acid (1.61% w / w) 490.46 Residue 21.34 Residue + acetic acid 511.80 butadiene 30.35 Reaction mixture at the end of the run 516.60 Estimated Butadiene Absorption 13.77 Water added to the mixture 200.05 Cyclohexane Extract 1 199.65 Recovered Cyclohexane 209.64 Cyclohexane Extract 2 201.46 Recovered Cyclohexane 212.33 Residue after acetic acid / water removal 12.08 Sample removed 8.97 Catalyst lost during sampling 0.17

Table 12- GC Data for Run 6

sample time Weight (g) Crotyl acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Act 6-1 0 4.57 0.000 0.000 0.000 Act 6-2 18 4.40 0.764 0.786 1.550

Conduct 7

Estimated catalyst concentration = 1.84%

Table 13-Mass Balance Data for Run 7

Technology Weight (g) Refilled acetic acid (0.98% w / w) 490.70 Residue 11.92 Residue + acetic acid 502.62 butadiene 32.33 Reaction mixture at the end of the run 504.37 Estimated Butadiene Absorption 10.47 Water added to the mixture 200.22 Cyclohexane Extract 1 202.81 Recovered Cyclohexane 245.47 Cyclohexane Extract 2 208.45 Recovered Cyclohexane 214.91 Residue after acetic acid / water removal 14.79 Sample removed 8.72 Catalyst lost during sampling 0.16

Table 14-GC Data for Implementation 7

sample time Weight (g) Crotyl acetate (% w / w) Sec-butenyl acetate (% w / w) Total C ₄ Acetate (% w / w) Act 7-1 0 4.57 0.004 0.000 0.004 Act 7-2 18 4.15 0.872 0.819 1.681

Table 15

Claims (20)

A process for preparing butenyl esters from butadiene, comprising reacting a hydrocarbon mixture comprising butadiene or butadiene with a saturated aliphatic monocarboxylic acid, wherein the catalyst comprises a ratio of the number of carbon atoms to the number of sulfonic acid groups in organic sulfonic acid. A process ranging from 1: 1 to 1: 0.15, containing organic sulfonic acids comprising at least two sulfonic acid groups per molecule, wherein the reaction is carried out in a liquid or mixed liquid / gas phase. delete delete The process of claim 1 wherein said organic sulfonic acid catalyst comprises 2 to 30 carbon atoms. delete The process of claim 1 wherein the reaction mixture comprises from 0.2 to 10% by weight of catalyst, based on the weight of the total reaction mixture. The process according to claim 4, wherein the organic sulfonic acid catalyst is selected from: 1,2-ethane disulfonic acid, benzene-1,2-disulfonic acid, benzene-1,3-disulfonic acid, benzene-1,4- Disulfonic acid, naphthalene-1,5-disulfonic acid, naphthalene-2,6-disulfonic acid and naphthalene-2,7-disulfonic acid, 4-chlorobenzene-1,3-disulfonic acid, 4-fluorobenzene-1, 3-disulfonic acid, 4-bromobenzene-1,3-disulfonic acid, 4,6-dichlorobenzene-1,3-disulfonic acid, 2,5-dichlorobenzene-1,3-disulfonic acid, 2,4, 6-trichlorobenzene-1,3-disulfonic acid, 3-chloronaphthalene-2,6-disulfonic acid, benzene trisulfonic acid and naphthalene trisulfonic acid. The process of claim 1 wherein the saturated aliphatic monocarboxylic acid used in the invention is a C ₂ to C ₆ acid. The process of claim 1 wherein the reaction of reacting a hydrocarbon mixture comprising butadiene or butadiene with a saturated aliphatic monocarboxylic acid is carried out in a liquid or mixed liquid / gas phase in the presence of a solvent. delete The method of claim 1 wherein the polymerization inhibitor is included in the reaction. delete The process of claim 1 wherein the relative molar ratio of butadiene to carboxylic acid reactant in the addition reaction is in the range of 5: 1 to 1:50. delete The process of claim 1 wherein the reaction of the butadiene hydrocarbon mixture or butadiene with a saturated aliphatic monocarboxylic acid is carried out in the presence of excess aliphatic monocarboxylic acid reactant as a solvent. delete delete delete delete delete

Images