EP2379485A1

EP2379485A1 - Method for manufacturing biomass-derived methyl methacrylate

Info

Publication number: EP2379485A1
Application number: EP10706693A
Authority: EP
Inventors: Jean-Luc Dubois
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2009-01-06
Filing date: 2010-01-05
Publication date: 2011-10-26
Also published as: JP2015180637A; WO2010079293A1; FR2940801B1; BRPI1006068A2; US20110301316A1; CN102341365A; CN106928056A; JP2012514590A; FR2940801A1; JP2017155055A

Abstract

The invention relates to a method for manufacturing methyl methacrylate by oxidizing methacrolein into methacrylic acid and the esterification of the latter through methanol, characterized in that at least one fraction of at least one of either the methacrolein or methanol in said reaction was obtained through a reaction or series of reactions using the biomass.

Description

PROCESS FOR THE PRODUCTION OF METHYL METHACRYLATE DERIVED

BIOMASS

The present invention relates to a process for producing a methyl methacrylate derived from biomass.

Methyl methacrylate is the starting material for many polymerization or copolymerization reactions.

It is the monomer for the manufacture of poly (methyl methacrylate) (PMMA), known under the trade names ALTUGLAS ^® and PLEXIGLAS ^® . It is in the form of powders, granules or plates, the powders or granules used to mold various articles, such as articles for the automobile, household and office items, and the plates found use in the signs and displays, in the fields of transportation, building, lighting and sanitary, as noise barriers, for works of art, flat screens, etc.

Methyl methacrylate is also the starting material for the organic synthesis of higher methacrylates, which, like it, are used in the preparation of acrylic emulsions and acrylic resins, serve as additives for polyvinyl chloride, enter As comonomers in the manufacture of many copolymers such as methyl methacrylate-butadiene-styrene copolymers, serve as additives for lubricants, and have many other applications among which one could mention medical prostheses, flocculants, products of maintenance, etc. Acrylic emulsions and resins have applications in the fields of paints, adhesives, paper, textiles, inks, etc. Acrylic resins serve also in the manufacture of plates, having the same applications as the PMMA.

Methyl methacrylate can be obtained in a variety of ways, one of which consists of an oxidation of methacrolein to methacrylic acid and esterification of the latter with methanol.

Patent Applications EP 1,994,978 and EP 1,995

231 describe a process for the manufacture of methyl methacrylate by esterification of methacrylic acid with methanol, the methacrylic acid being obtained by oxidation of methacrolein from the oxidation of isobutene.

In EP 1 813 586 and US Pat. No. 3,819,685, the oxidation of methacrolein is carried out in the presence of methanol leading directly to the production of methyl methacrylate.

In GB 2,094,782, methyl methacrylate is produced from methacrolein derived from isobutyraldehyde obtained by hydroformylation of propylene in the presence of hydrogen and carbon monoxide. In EP 058 927, methacrolein is obtained by reaction of propanal with formalin and a secondary amine in the presence of an acid.

The raw materials used for these syntheses of methyl methacrylate are mainly of petroleum origin or of synthetic origin, thus containing numerous sources of CO2 emission, which consequently contribute to the increase of the greenhouse effect. Given the dwindling global oil reserves, the source of these raw materials will gradually be exhausted.

Raw materials from biomass are renewable sources and have a reduced impact on the environment. They do not require all the refining steps, very expensive in energy, petroleum products. The production of fossil CO2 is reduced so that they contribute less to global warming. Especially for its growth, the plant has consumed atmospheric CO2 at a rate of 44g of CO2 per mole of carbon (or for 12 g of carbon). So the use of a renewable source begins by decreasing the amount of atmospheric CO2. The vegetable matter has the advantage of being able to be cultivated in large quantity, according to the demand, on most of the terrestrial globe.

It therefore appears necessary to have synthetic methyl methacrylate synthesis processes that are not dependent on raw material of fossil origin, but instead using biomass as raw material.

Biomass is the raw material of plant or animal origin naturally produced. This plant material is characterized by the fact that the plant for its growth has consumed atmospheric CO2 while producing oxygen. The animals for their growth consumed this vegetable raw material and thus assimilated carbon derived from atmospheric CO2. The purpose of the present invention is therefore to respond to certain concerns of sustainable development.

The subject of the present invention is therefore a process for the manufacture of methyl methacrylate by oxidation of methacrolein to methacrylic acid and esterification thereof with methanol, characterized in that at least one fraction of at least one of methacrolein and methanol in this reaction was obtained by a reaction or a succession of reactions from the biomass.

The said oxidation and said esterification may be carried out in two successive stages or else simultaneously.

It has been possible to obtain at least a fraction of the methanol by pyrolysis of the wood or by gasification of all materials of animal and / or vegetable origin, leading to a synthesis gas composed essentially of carbon monoxide and hydrogen, or by fermentation at from plant crops such as wheat, sugar cane or beet, giving fermentable products and therefore alcohol, at least a fraction of the synthesis gas to prepare the methanol may also come from the recovery of waste liquor and bleaching of the manufacture of cellulosic pulps.

According to a first embodiment, it has been possible to obtain at least one fraction of methacrolein by oxidation of at least one of isobutene, tert.-butanol and / or a mixture of both, isobutene and if necessary mixed with tert. -butanol which may be derived from the dehydration of isobutanol, at least a fraction of isobutanol which may have been obtained by distillation of a Fusel oil, and / or by fermentation in the presence of at least one yeast of minus a plant material, which is generally in a hydrolysed form before fermentation, the fermentation being followed by a distillation step to recover the isobutanol in the form of an aqueous solution, which is then subjected to a concentration step and / or by condensation of methanol with ethanol, the methanol and / or the ethanol being derived from the biomass. According to a second embodiment, it has been possible to obtain at least one fraction of methacrolein by oxidative dehydrogenation of isobutyraldehyde, at least a fraction of which may be derived from the reaction of propylene with a synthesis gas and / or or the oxidation of isobutanol, at least a portion of the isobutanol which may have been obtained by distillation of a Fusel oil, and / or by fermentation in the presence of at least one yeast of at least one material plant, which is generally in a hydrolysed form prior to fermentation, the fermentation being followed by a distillation step to recover isobutanol in the form of an aqueous solution, which is then subjected to a concentration step, and or by condensation of methanol with ethanol, the methanol and / or ethanol being derived from the biomass; at least a fraction of the synthesis gas that can come from the gasification of any material of animal or vegetable origin and / or the recovery of waste liquor and bleaching of the manufacture of cellulosic pulps.

It was possible to obtain at least a fraction of propylene by dehydration of isopropanol, itself obtained by fermentation of biomass, or metathesis reaction of ethylene and 2-butene, themselves obtained by dehydration of a mixture of alcohols, comprising at least ethanol and 1-butanol, resulting from the fermentation of biomass.

According to a third embodiment, it has been possible to obtain at least a fraction of the methacrolein by reaction of propanaldehyde with formaldehyde, at least a fraction of the propanaldehyde which can be derived from the hydrogenation of acrolein, at least a fraction of the latter derived from dehydration of glycerol, at least a fraction of it having been obtained as a by-product of the manufacture of biofuels from oleaginous plants such as rapeseed, sunflower or soy containing triglycerides, hydrolysis or transesterification of these triglycerides making it possible to form glycerol outside, respectively, fatty acids and fatty esters; and at least one fraction of the formaldehyde by oxidation of methanol, at least a fraction of the methanol involved having been obtained by pyrolysis of the wood or by gasification of any material of animal or vegetable origin leading to a synthesis gas composed essentially of monoxide carbon and hydrogen, or by fermentation from crops such as wheat, corn, sugar cane or beetroot, giving fermentable products and therefore alcohol.

The subject of the present invention is also the use of methyl methacrylate manufactured by the process as defined above, as a monomer for the manufacture of poly (methyl methacrylate), as a starting material for the organic synthesis of higher methacrylates, such as product used in the preparation of acrylic emulsions and acrylic resins, as an additive for polyvinyl chloride, as a comonomer in the manufacture of copolymers and as a lubricant additive.

Valorisation of biomass in methanol

As indicated above, the methanol is obtained by pyrolysis of the wood, by gasification of all materials of animal or vegetable origin, leading to a gas of synthesis consisting essentially of carbon monoxide and hydrogen which is optionally reacted with water by the reaction of gas with water to adjust the ratio H ₂ / CO in the proportions appropriate for the synthesis of methanol, or by fermentation from crops of plants such as wheat, corn, sugar cane or beet, giving fermentable products and thus alcohol.

The materials of animal origin are, by way of non-limiting examples, fish oils and fats, such as cod liver oil, whale oil, sperm whale, dolphin oil, seal oil, sardine oil, herring oil, squales, oils and fats of cattle, pigs, goats, equines, and poultry, such as tallow, lard, milk fat, bacon, chicken fat, beef, pork, horse, and others.

Plant-based materials are, by way of non-limiting examples, ligno-cellulosic residues from agriculture, cereal straw fodder, such as wheat straw, straw or maize residues; cereal residues as maize residues; cereal flours, such as wheat flour; cereals such as wheat, barley, sorghum, maize; wood, waste and scrap wood; grains; sugar cane, sugar cane residues; shoots and stems of peas; beetroot, molasses such as beet molasses; Jerusalem artichokes; potatoes, potato tops, potato residues; starch; mixtures of cellulose, hemicellulose and lignin, and the black liquor of stationery, which is a carbon-rich material.

According to one particular embodiment of the invention, the synthesis gas for preparing methanol comes from the recovery of waste liquor and bleaching of cellulosic pulp manufacturing. Reference may be made to documents EP 666 831 and US Pat. No. 7,294,225 to Chemrec, which notably describe the gasification of waste liquors from the manufacture and bleaching of cellulose, and the obtaining of methanol, as well as on pages 92-105 of the work. Petrochemical Processes Technical and Economic Characteristics - Volume 1 Editions Technip - synthesis gas and its derivatives, which deals with obtaining methanol from synthesis gas.

Valorisation of biomass into isobutanol by distillation of Fusel oils also called Fusel alcohols.

Ethanol fermentation, fermentation of biomass such as sugar in ethanol, leads to alcohols heavier than ethanol, in the proportion of about 5 kg per ton of ethanol. This mixture of alcohols is mainly composed of alcohols with 5, 4 and 3 carbon atoms such as amyl and isoamyl alcohols, isobutanol and propanol. It is then possible to isolate the isobutanol from this mixture of alcohols, in particular by distillation technologies.

Valorisation of biomass in isobutanol by condensation of methanol with ethanol

Condensation of methanol with ethanol leads, according to the Guerbet reactions, to a mixture of propanol and isobutanol (2-methyl-1-propanol) with the minor presence of other branched alcohols such as 2-methyl-1 butanol. The constitution of this mixture of alcohols depends partly on the nature of the catalyst (s) for the Guerbet reactions, on the other hand the ratio between the two reagents, methanol and ethanol. It is then possible to isolate the isobutanol from this mixture of alcohols, for example by distillation technologies. The reaction mechanism of Guerbet reactions involves the formation of formaldehyde and acetaldehyde from methanol and ethanol respectively, which condense to produce propenal, which is reduced to propanol. Condensation of formaldehyde with propanal leads to isobutanol.

These various reactions and their conditions of use are described in particular in the article by E. S. Oison et al, Applied Biochemistry and Biotechnology, Vol 113-116, 2004 p 913-930. For the Guerbet reaction, it was possible to obtain methanol from biomass as described above, and ethanol by fermentation of plant material that can be chosen in particular from sugars, starch and plant extracts containing them. These include beetroot, sugar cane, cereals such as wheat, barley, sorghum or maize, and potatoes, although this list is not exhaustive. It can alternatively be biomass (mixture of cellulose, hemicellulose and lignin). The fermentation is then obtained, for example with the aid of Saccharomyces cerevisiae or its mutant, ethanol.

These fermentation processes are well known to those skilled in the art. They include for example the fermentation of vegetable matter in the presence of one or more yeasts or mutants of these yeasts (naturally modified microorganisms in response to chemical or physical stress), followed by distillation to recover the alcohol, in particular ethanol, in the form of of a more concentrated aqueous solution which is then treated to further increase its molar concentration of alcohol such as ethanol. Ethanol is generally obtained in mixture with heavier alcohols, called Fusel alcohols, the composition of which depends on the plant material used and the fermentation process. The ethanol produced by fermentation can be purified, for example by absorption on filters of the molecular sieve type, carbon black or zeolites.

Valorization of biomass in propylene

As indicated above, according to a first variant, propylene is obtained by dehydration of isopropanol, the isopropanol being obtained by fermentation of renewable raw materials in the presence of one or more suitable microorganisms, this microorganism may possibly have been modified. naturally by a chemical or physical constraint, or genetically we speak then mutant.

As biomass, we can use vegetable matter; materials of animal origin or materials of plant or animal origin from recovered materials (recycled materials). For the purposes of the invention, the materials of plant origin contain at least sugars and / or polysaccharides such as starch, cellulose or hemi-cellulose.

Vegetable materials containing sugars are mainly sugar cane and sugar beet, and maple, date palm, sugar palm, sorghum, American agave; plant materials containing starches are mainly cereals and legumes such as maize, wheat, barley, sorghum, wheat, rice, potato, cassava, sweet potato, or seaweed.

As renewable raw materials, it is also possible to use cellulose or hemicellulose which, in the presence of suitable microorganisms, can be converted into materials comprising sugar. Among these renewable materials are straw, wood, paper, which can advantageously come from recovered materials.

Among the materials from recovered materials include plant or organic waste including sugars and / or polysaccharides.

Preferably renewable raw materials are plant materials.

In the case of polysaccharides, the plant material used is generally in hydrolysed form before the fermentation step. This preliminary hydrolysis step thus allows, for example, the saccharification of starch to transform it into glucose, or the transformation of sucrose into glucose.

Advantageously, the microorganisms used for the fermentation are Clostridium beijerinckii, Clostridium aurantibutyricum or Clostridium butylicum and their mutants, preferably immobilized on a support of the polymer fiber or calcium type.

The fermentation of these raw materials leads essentially to the production of isopropanol and / or butanols with possibly acetone. The fermentation step is advantageously followed by a purification step, for example a distillation intended to separate the isopropanol from the other alcohols. The dehydration is carried out in the presence of oxygen and water using a catalyst based on gamma-alumina, such as the catalyst marketed by EUROSUPPORT under the trade name ESM 110® (undoped trilobal alumina containing about -about 0.04% - residual Na2 <0).

The operating conditions of dehydration are part of the general knowledge of those skilled in the art, as an indication, the dehydration is generally carried out at a temperature of the order of 400 ^° C. According to a second variant, propylene is obtained by reaction. of metathesis of ethylene and 2-butene, themselves being obtained by dehydration of a mixture of alcohols, comprising at least ethanol and 1-butanol, resulting from the fermentation of biomass using Clostridium beijerinckii or one of his mutants.

The dehydration of ethanol and 1-butanol to produce ethylene and 1-butene is carried out under the same conditions as the dehydration of isopropanol described above. Then is carried out a hydroisomerization reaction of 1-butene to 2-butene. Finally, the metathesis of ethylene and 2-butene leads to the formation of propylene.

The details of the hydro-isomerization and metathesis reactions are for example mentioned in the patent application FR 2,880,018.

Valorisation of biomass into glycerol

Glycerol is obtained from oleaginous plants such as rapeseed, sunflower or soy, containing oils (triglycerides) or animal fats. A step of hydrolysis or transesterification of triglycerides is carried out to form, with glycerol, respectively fatty acids or fatty esters. For example, this transesterification can be carried out by reacting the crude oil in a stirred reactor in the presence of an excess of alcohol (for example methanol), preferably with a basic catalyst (such as sodium methoxide or sodium hydroxide). . To carry out the hydrolysis reaction, the crude oil is reacted in the presence of an excess of water, preferably with an acid catalyst. This transesterification or hydrolysis reaction is preferably carried out at a temperature of between 30 and 250 ^° C., and preferably between 40 and 120 ^° C. Preferably, the reactor is continuously fed to maintain the water / acid molar ratio. or alcohol / ester greater than or equal to 2/1. At the end of the reaction, the glycerol is separated from the mixture obtained by decantation.

The present invention thus makes it possible to obtain a methyl methacrylate having at least a portion of its carbons of renewable origin.

A renewable raw material is a natural resource, animal or vegetable, whose stock can be reconstituted over a short period on a human scale. In particular, this stock must be renewed as quickly as it is consumed.

Unlike materials made from fossil materials, renewable raw materials contain ¹⁴ C in the same proportions as atmospheric CO2. All carbon samples from living organisms (animals or plants) are actually a mixture of 3 isotopes: ¹² C (representing about 98.892%), ¹³ C (about 1.108%) and ¹⁴ C (traces: 1, 2.10 ^"10 %) .The ¹⁴ C / ¹² C ratio of living tissues is identical to that of the atmosphere.In the environment, ¹⁴ C exists in two predominant forms: in mineral form , that is to say carbon dioxide (CO2), and in organic form, that is to say carbon incorporated in organic molecules.

In a living organism, the ¹⁴ C / ¹² C ratio is kept constant by the metabolism because the carbon is continuously exchanged with the environment. The proportion of ¹⁴ C is constant in the atmosphere, it is the same in the body, as long as it is alive, since it absorbs this ¹⁴ C as it absorbs ¹² C. The average ratio of ¹⁴ C / ¹² C is equal to 1, 2xlθ ^{~ 12} . Carbon 14 is derived from the bombardment of atmospheric nitrogen (14), and spontaneously oxidizes with oxygen in the air to give CO2. In our human history, the content of ¹⁴ C02 has increased as a result of atmospheric nuclear explosions, and has continued to decrease after stopping these tests.

¹² C is stable, that is to say that the number of atoms of ¹² C in a given sample is constant over time. ¹⁴ C is radioactive (each gram of carbon in a living being contains enough ¹⁴ C isotopes to give 13.6 disintegrations per minute) and the number of such atoms in a sample decreases over time (t ) according to the law :

n = no exp (-at),

where: - no is the number of ¹⁴ C at the origin (at the death of the creature, animal or plant),

n is the number of ¹⁴ C atoms remaining at the end of time t, - at. is the disintegration constant (or radioactive constant); it is connected to the half-life.

The half-life (or period) is the time after which any number of radioactive nuclei or unstable particles of a given species are halved by disintegration; the half-life Ti _{/ 2} is related to the disintegration constant a. by the formula a.Ti _{/ 2} = In 2. The half-life of ¹⁴ C is 5730 years. In 50,000 years the content

¹⁴ C is less than 0.2% of the initial content and therefore becomes difficult to detect. Petroleum products, or natural gas or coal therefore do not contain ¹⁴ C.

Given the half-life (Ti _{/ 2)} of ¹⁴ C, the ¹⁴ C content is substantially constant from the extraction of renewable raw materials, to the manufacture of methyl methacrylate according to the invention and even up at the end of its use.

The methyl methacrylate obtained according to the invention contains organic carbon derived from renewable raw materials; it is therefore characterized in that it contains ¹⁴ C.

In particular, at least 1% by weight of the carbon atoms of said methyl methacrylate is of renewable origin.

Preferably, at least 20% of the carbons of said methyl methacrylate are of renewable origin. Even more preferably, at least 40% of the carbons of said methyl methacrylate are of renewable origin. More particularly, at least 60%, and even more specifically at least 80% of the carbon atoms of said methyl methacrylate, are of renewable origin.

The methyl methacrylate obtained according to the invention contains at least 0.01 × ^{10 -10} % by weight, preferably at least 0.2 × ^{10 -10} %, of ¹⁴ C relative to the total mass of carbon. Even more preferably, said methyl methacrylate contains at least 0.4 × ^{10 -10} % of ¹⁴ C, more particularly at least 0.7 × ^{10 -10} % of ¹⁴ C, and even more specifically at least 0.9 × ^{10 -10} %. ¹⁴ C. in a preferred embodiment of the invention, methyl methacrylate obtained according to the invention contains 100% of organic carbon derived from renewable raw materials and therefore l, 2xlθ ^{~ 10%} by weight of ¹⁴ C the total mass of carbon. The ¹⁴ C content of methyl methacrylate can be measured, for example, according to the following techniques: by liquid scintillation spectrometry: this method consists in counting 'Beta' particles resulting from the decay of ¹⁴ C. The beta radiation obtained from a known mass sample (number of known carbon atoms) for a certain time. This 'radioactivity' is proportional to the number of ¹⁴ C atoms, which can be determined. The ¹⁴ C present in the sample emits β- radiation, which, in contact with the scintillating liquid (scintillator), give rise to photons. These photons have different energies (between 0 and 156 Kev) and form what is called a spectrum of ¹⁴ C. According to two variants of this method, the analysis relates to the CO2 previously produced by combustion of the carbon sample in a suitable absorbent solution, or on benzene after prior conversion of the carbon sample to benzene, by mass spectrometry: the sample is reduced in graphite or gaseous CO2, analyzed in a mass spectrometer. This technique uses an accelerator and a mass spectrometer to separate the ¹⁴ C ions of the ¹² C and thus determine the ratio of the two isotopes.

These methods of measuring the ¹⁴ C content of the materials are precisely described in ASTM D 6866 (including D6866-06) and ASTMD 7026 standards.

(in particular 7026-04). These methods compare the measured data on the analyzed sample with the data from a 100% renewable source reference sample to give a relative percentage of renewable carbon in the sample.

The measurement method preferably used in the case of methyl methacrylate is the mass spectrometry described in ASTM D6866-06.

The following Examples illustrate the present invention without however limiting its scope. In these Examples, parts and percentages are by weight unless otherwise indicated.

Example 1 Manufacture of CO / H2 Synthesis Gas and Carbon Monoxide Isolation

In the present example, an ethanol-water mixture is used, the ethanol being obtained by ethanol fermentation of sugar, as follows:

A water-sugar mixture (10 kg of sugar) is poured into a 50-liter plastic tank. 0.25 l of baker's yeast mixed beforehand with 0.25 l of warm water, a dose of Calgon (water softener) are added to the mixture and the mixture is left to macerate for 14 days at a temperature of 25 ^° C. To limit the formation of acetic acid, the container is covered with a lid provided with a valve. At the end of this step, the mixture is filtered, decanted and the solution is distilled to recover the azeotrope of ethanol, 96% in water.

This ethanol-water mixture is subjected to a pressure of 30 bar and at a temperature of 900 ^° C., with a Ni / Alumina catalyst. On leaving the reactor, the excess water is condensed as well as the heavy impurities.

The CO / H ₂ mixture is cryogenically separated, passing the mixture through a liquid nitrogen trap to retain the CO. The condensed gas is then reheated to separate the CO from other impurities (methane, CO ₂ , etc.).

Example 2 Manufacture of Methanol from Synthetic Gas

For the synthesis of methanol, the synthesis gas of Example 1 is used. The composition of this gas is adjusted to have an H2 / CO / CO2 ratio of 71/23/6 and the CO2 content is 6%. The total pressure of the gas is 70 bars.

A commercial catalyst Cu-Zn-Al-O, MegaMax 700 is used. The reactor is supplied with the gas mixture at 70 bar with a VVH of 1000Oh ^-1 , and passes over the catalyst at a temperature of 240 ^° C. The mixture produced gases are then decompressed at atmospheric pressure and the methanol produced is isolated by distillation.

The selectivity to methanol is 99% and the methanol yield is 95%.

Example 3: Manufacture of isobutanol Isobutanol can be isolated from a mixture of so-called fusel alcohols. In this case, a mixture available on the market is used. This mixture contains 12.4 wt% ethanol, 3.5 wt% n-propanol, 9.5 wt% isobutanol and 74.6 wt% isoamyl alcohol. All percentages are given without taking into account water. The mixture of fusel alcohols is obtained from an ethanol distillery. The fusel alcohol mixture is first treated with an equivalent volume of hexane, and the water is removed by phase separation. After removal of water, sodium sulfate is added (about 0.15 kg of salt per liter of fusel alcohol) to reduce the water content in the fusel alcohol.

The alcohol mixture is then distilled into different fractions. The fraction containing isobutanol is isolated and the purity thereof is monitored by gas chromatography. The isobutanol-rich fraction also contains traces of ethanol (5 wt%) and isoamyl alcohol (7 wt%). The mixture is then taken up for further distillation in order to have isobutanol containing less than 1% of each of the impurities.

Example 4: Manufacture of Isobutene

The isobutanol obtained in Example 3 is evaporated with steam to create an equimolar mixture of isobutanol and water.

In an installation, the isobutanol is vaporized in a vaporizer, then preheated in a heat exchanger, before being injected at the top of a 127 mm diameter reactor containing a catalyst bed heated to 300-400 ⁰ C and consisting of an ESM110 ^® alumina layer from EUROSUPPORT, representing a volume of 12700 cm ³ and a mass of 6500 g, the ratio of the volume flow rate of isobutanol to the catalyst volume being ¹ h ^{-1, the} mixture of water and isobutene produced in the reactor is cooled in the exchanger thermal, before being sent to a gas-liquid separator where isobutene and water (possibly mixed with by-products) are separated.

Example 5 Manufacture of Methacrolein from Isobutene

The isobutene obtained in Example 4 is used.

A reactor 2.54 cm in diameter and 1 m long immersed in a bath of molten salt at a temperature of 339 ^° C. is fed with a VVH of 1000 h ^-1 with an O ₂ / isobutene / H ₂ 0 mixture. / N ₂ 2/1 / 2.5 / 12 The reactor is charged with Nippon Kayaku YS79-1 catalyst The hot point in the catalyst bed reaches 412 ^° C.

After 300 hours of operation, the conversion is 99%, the methacrolein yield is 79%, and the methacrylic acid yield is 4.0%.

Example 6 Manufacture of Methacrylic Acid from Isobutene

Two series reactors 2.54 cm in diameter and 1 m long immersed in baths of molten salt at temperatures of 367 and 313 ⁰ C respectively are fed with a VVH of 1000 h with a mixture 0 ₂ / isobutene / H ₂ O / N ₂ 2/1 / 2.5 / 12. The first reactor is charged with Nippon Kayaku's YS79-1 catalyst, and the second with Nippon Kayaku's K80 catalyst. The hot spot in the second catalyst bed reaches 330 ^° C. After 300 hours of operation, the conversion is 99%, and the methacrylic acid yield is 37.5%, and the conversion of methacrolein between the first and the second reactor is 52%.

Example 7: Manufacture of methyl methacrylate from methacrylic acid.

For this step, the methacrylic acid obtained in the preceding step and the methanol obtained according to Example 2 are used. The acid is brought into contact in the presence of a stabilizer (800 ppm of EMHQ) with a ratio of methacrylic acid. / methanol of 5, in a column fed from bottom to top containing a K2431 resin Lanxess maintained at 85 ⁰ C with a residence time of 70 minutes.

The product is collected and analyzed. After 15 hours of continuous operation the product contains 75% methacrylic acid and 18% methyl methacrylate which is recovered.

Claims

1 - Process for the manufacture of methyl methacrylate by oxidation of methacrolein to methacrylic acid and esterification thereof with methanol, characterized in that at least a fraction of at least one of methacrolein and methanol in this reaction was obtained by a reaction or a succession of reactions from the biomass. 2 - Process according to claim 1, characterized in that one leads said oxidation and said esterification in two successive steps.

3 - Process according to claim 1, characterized in that one leads said oxidation and said esterification simultaneously.

4 - Process according to one of claims 1 to 3, characterized in that one obtained at least a fraction of methanol by pyrolysis of wood or gasification of any material of animal origin and / or plant, leading to a synthesis gas consisting essentially of carbon monoxide and hydrogen, or by fermentation from crops of plants such as wheat, sugar cane or beet, giving fermentable products and therefore alcohol, at least one fraction of the synthesis gas to prepare the methanol may also come from the recovery of waste liquor and bleaching of the manufacture of cellulosic pulps.

5 - Process according to one of claims 1 to 4, characterized in that there is obtained at least a fraction of methacrolein by oxidation of at least one of isobutene, tert. butanol and / or a mixture of both, isobutene if appropriate in admixture with tertiary butanol which may be derived from the dehydration of isobutanol, at least one fraction of isobutanol which may have been obtained by distillation of a Fusel oil, and / or by fermentation in the presence of at least one yeast of at least a plant material, which is generally in a hydrolysed form before fermentation, the fermentation being followed by a distillation step to recover the isobutanol in the form of an aqueous solution, which is then subjected to a concentration step, and / or by condensation of methanol with ethanol, the methanol and / or ethanol being derived from the biomass.

6 - Process according to one of claims 1 to 5, characterized in that at least a fraction of the methacroleine is obtained by oxidative dehydrogenation of isobutyraldehyde, at least a fraction of which may be derived from the reaction of propylene with a synthesis gas and / or the oxidation of isobutanol, at least one fraction of isobutanol which may have been obtained by distillation of a Fusel oil, and / or by fermentation in the presence of at least one yeast of at least one plant material, which is generally in a hydrolysed form before fermentation, the fermentation being followed by a distillation step to recover the isobutanol in the form of an aqueous solution, which is then subjected to a concentration step, and / or by condensation of methanol with ethanol, the methanol and / or ethanol being derived from the biomass; at least a fraction of the synthesis gas that can come from the gasification of any material of animal or vegetable origin and / or the recovery of waste liquor and bleaching of the manufacture of cellulosic pulps. 7 - Process according to claim 6, characterized in that at least a fraction of propylene is obtained by dehydration of isopropanol, itself obtained by fermentation of biomass, or metathesis reaction of ethylene and 2-butene, themselves obtained by dehydration of a mixture of alcohols, comprising at least ethanol and 1-butanol, derived from the fermentation of biomass.

8 - Process according to one of claims 1 to 6, characterized in that one obtained at least a fraction of the methacrolein by reaction of formaldehyde propanaldehyde, at least a fraction of the propanaldehyde may be derived from the hydrogenation of acrolein, at least a fraction of it derived from dehydration of glycerol, at least a fraction of it having been obtained as a by-product of the manufacture of biofuels from oleaginous plants such as rapeseed, sunflower or soybean containing triglycerides, hydrolysis or transesterification of these triglycerides to form glycerol outside respectively of fatty acids and fatty esters; and at least one fraction of the formaldehyde by oxidation of methanol, at least a fraction of the methanol involved having been obtained by pyrolysis of the wood or by gasification of any material of animal or vegetable origin leading to a synthesis gas composed essentially of monoxide carbon and hydrogen, or by fermentation from crops such as wheat, corn, sugar cane or beetroot, giving fermentable products and therefore alcohol.

9 - Use of methyl methacrylate containing at least 0.4x10 ^-10 % by mass of ¹⁴ C on the mass total carbon produced by the process as defined in one of claims 1 to 8, as a monomer for the manufacture of poly (methyl methacrylate), as starting material of the organic synthesis of higher methacrylates, as a product used in the preparation acrylic emulsions and acrylic resins, as an additive for polyvinyl chloride, as a comonomer in the manufacture of copolymers and as a lubricant additive.