EP2362853A1

EP2362853A1 - Method for the production of a biomass-derived methyl methacrylate

Info

Publication number: EP2362853A1
Application number: EP09768206A
Authority: EP
Inventors: Jean-Luc Dubois
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2008-11-27
Filing date: 2009-11-17
Publication date: 2011-09-07
Also published as: FR2938838B1; JP2015134826A; JP2012509927A; JP2017066149A; WO2010061097A1; FR2938838A1

Abstract

The invention relates to a method for producing methyl methacrylate by reacting alpha-hydroxyisobutyramide with methyl formate in order to obtain methyl alpha-hydroxyisobutyrate and formamide, said methyl alpha-hydroxyisobutyrate being dehydrated to form methyl methacrylate, characterised in that at least one fraction of the methyl formate used in said reaction and/or at least one fraction of the alpha-hydroxyisobutyramide used in said reaction is obtained by a reaction or a series of reactions involving 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 is to hydrate the acetone cyanohydrin to α-hydroxyisobutyramide [(H ₃ C) (OH) (CH ₃ ) C-CO-NH ₂ ] which, reacting with methyl formate [HCOOCH ₃ ], produces methyl α-hydroxyisobutyrate [(H ₃ C) (OH) (CH ₃ ) -COOCH ₃ ] and formamide [HCONH ₂ ]. Formamide is recycled after conversion to HCN + H ₂ O, HCN reacts with acetone to give acetone cyanohydrin, and methyl α-hydroxyisobutyrate is dehydrated to methyl methacrylate.

EP 407 811 illustrates such a process leading to the production of methyl methacrylate with a yield of 90%.

The raw materials used for these syntheses of methyl methacrylate are mainly of petroleum origin or of synthetic origin, thus containing numerous sources of CO ₂ emissions, 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 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 CO ₂ is reduced so that they contribute less to global warming. Especially for its growth, the plant has consumed atmospheric CO ₂ at the rate of 44 g of CO ₂ per mole of carbon (or for 12 g of carbon). So using a renewable source starts with reduce 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 methods of synthesis of methyl methacrylate not dependent on raw material of fossil origin, but rather 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 reaction of alpha-hydroxyisobutyramide with methyl formate to give methyl alpha-hydroxyisobutyrate and formamide, methyl alpha-hydroxyisobutyrate being dehydrated methyl methacrylate, characterized in that at least a fraction of the methyl formate involved in this reaction and / or at least a fraction of the alpha-hydroxyisobutyramide involved in this reaction has been obtained by reaction or a succession of reactions from the biomass.

At least one fraction of methyl formate was obtained by carbonylation of methanol using carbon monoxide extracted from a synthesis gas compound essentially carbon monoxide and hydrogen, at least a fraction of the synthesis gas has been obtained by gasification of any material of animal or vegetable origin or from the recovery of waste liquor and bleaching of the manufacture of cellulosic pulps.

At least one fraction of the methyl formate was obtained by carbonylation of methanol, at least a fraction of the methanol having been obtained by pyrolysis of the wood or by gasification of any material of animal or vegetable origin leading to a synthesis gas 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 at plant crops such as wheat, corn, sugar cane or beet, giving fermentable products and therefore alcohol, at least a fraction of the synthesis gas to prepare the methanol that can also come from the recovery of waste liquor and bleaching of cellulosic pulp manufacturing.

At least a portion of the alpha-hydroxyisobutyramide has been obtained by hydration of acetone cyanohydrin, at least a portion of the acetone cyanohydrin having been obtained by reaction of acetone with hydrocyanic acid, at least a part thereof which can come from the recycling of formamide, at least one of acetone and hydrocyanic acid having been obtained by a reaction or a succession of reactions from the biomass. Please refer to the following paragraphs entitled "Valorisation of biomass in acetone" and "Valorisation of biomass in hydrogen cyanide" for the details of these reactions or successions of reactions from the biomass.

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, methanol is obtained by pyrolysis of the wood, by gasification of all materials of animal or vegetable origin, leading to a synthesis gas composed 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 appropriate proportions to the synthesis of methanol, or by fermentation from crops of plants such as wheat, corn, cane sugar or beet, giving fermentable products and therefore 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, of 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 a particular embodiment of the invention, the synthesis gas for preparing the methanol comes from the recovery of residual liquor and the bleaching of the manufacture of cellulosic pulps. 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 carbon monoxide Carbon monoxide is obtained by gasification of all materials of animal or vegetable origin, leading to a synthesis gas composed essentially of carbon monoxide and hydrogen, from which carbon monoxide is extracted.

Valorisation of biomass in acetone

According to a first embodiment, it was possible to obtain acetone by aceto-butyl fermentation of C ₆ and C ₅ sugars, resulting in an acetone-butanol mixture, where appropriate with ethanol, from which acetone was separated for example by distillation, in particular azeotropic distillation or by membrane separation (for example on pervaporation membranes) or separation on silicalite (Journal of the French Petroleum Institute, Vol 36, No. 3, 1981 , pp 339-347, Biotechnology Letters Vol 4, No. 11, pp 759-760 (1982), Advances in Applied Microbiology, Volume 31, 1986, pp 61-92, Ind Prog Microbiol 3 (190) 73-90. Separation, Science and Technology [28 (13 & 14), pp 2167-2178, 1993], Biotechnology Letters, Vol 4, No. ¹¹ , 759-760 (1982)).

The Ce and C ₅ sugars have advantageously been obtained from a material with a high sugar content chosen in particular from the lignocellulosic residues of agriculture and all materials of plant origin, such as 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 molasses beets; Jerusalem artichokes; potatoes, potato tops, potato residues; starch; mixtures of cellulose, hemicellulose and lignin; where appropriate subjected to mechanical treatment, such as shredding, grinding, extrusion, and / or chemical treatment, such as acid or alkaline water vapor treatment, and / or enzymatic hydrolysis treatment to release the C ₆ and C ₅ sugars.

Mechanical and chemical pretreatments aim at decreasing the crystallinity of cellulose by breaking bonds and increasing the contact surface of cellulose with enzymes.

The hydrolysis step notably allows the saccharification of the starch to transform it into glucose or the transformation of sucrose into glucose.

In particular, aceto-butyl fermentation was conducted using anaerobic bacteria such as Clostridium beijerinckii, such as VPI 5481 (ATCC 25732), 4635, 2697, 4419 (ATCC 11914), Clostridium butylicum, such as VPI 13436 ( NRRLB-592), Clostridium aurantibutyricum, such as VPI 4633 (ATCC 17777), 10789 (NCIB 10659), Clostridium acetobutylicum, such as VPI2673 (McClung 633), 13697 (ATCC 4259), 13698 (NRRL B-527 <- ATCC824) , 13693 (ATCC8529), 2676 (McClung 635), Clostridium toanum, their mutants or genetically modified organisms (Applied and Environmental Microbiology, Mar. 1983, p 1160-1163, Vol.45, No. 3, Biotechnology Letters Vol 4, N 8 (1982) 477-482).

These fermentation processes are known to those skilled in the art who are able to choose the best working conditions for a given type of plant material (Microbiological Reviews, Dec 1986, Vol 50 No. 4, p 484-524, Bioresource Technology 42 (1992) 205-217; Appl Microbiol Biotechnol (1985) 23: 92-98; Energy from Biomass, W. Paiz, Elsevier, Applied Science, London (1985) p 692-696).

According to a second embodiment, it was possible to obtain acetone by hydrothermal liquefaction at 573 ° C.

K sewage sludge to obtain a black water containing hydrocarbons, then catalytic cracking of said black water in a steam atmosphere on a zirconia or zirconia / alumina catalyst supported on an iron oxide, and then separating the acetone as indicated above, namely for example by distillation, in particular azeotropic distillation, or by membrane separation or separation on silicalite (Applied Catalysis B: Environmental 68 (2006) 154-159).

According to a third embodiment, it was possible to obtain acetone by catalytic conversion of palm oil residues on a zirconia or zirconia / alumina catalyst supported on an iron oxide and then separation of the acetone as indicated above, for example by distillation, in particular azeotope distillation, or by membrane separation or separation on silicalite (Applied Catalysis B: Environmental 68 (2006) 154-159).

Valorisation of biomass into hydrogen cyanide

According to a first embodiment, it has been possible to obtain hydrocyanic acid by ammoxidation of methane, the methane having been obtained by fermentation in the absence of oxygen of animal and / or vegetable organic matter, such as pig slurry. , household waste, agro-industrial waste, leading to a biogas compound methane and carbon dioxide, the carbon dioxide being removed by washing the biogas with a basic aqueous solution of sodium hydroxide, potassium hydroxide or amine, or by water under pressure, or by absorption into a solvent such as methanol.

This fermentation, also called anaerobic digestion, occurs naturally or spontaneously in landfills containing organic waste, but can be carried out in digesters, for example to treat sewage sludge, industrial or agricultural organic waste, pig manure, garbage.

Preferably, the fermented mixture contains animal droppings, which serve as a nitrogen input necessary for the growth of the microorganisms that ferment the biomass into methane. Reference can be made to the various methanization technologies of the state of the art, in the article "Review of Current Status of Anaerobic Digestion Technology for Municipal Solid Waste Treatment", November 1998, RISE-AT and to the various biological processes that exist. for the treatment of waste water, such as, for example, the Linde Laran® process.

Ammoxidation of methane can be mentioned in which ammonia (where appropriate obtained from the biomass) is reacted with methane in the presence of air and optionally with oxygen on a catalyst composed of platinum-containing rhodium-plated canvases. a temperature ranging from 1050 to 1150 ^° C. Generally, the molar ratio CH4 / NH3 ranges from 1.0 to 1.2, the molar ratio (CH4 + NH3) / total is from 1.6 to 1.9; the pressure is usually 1 to 2 bar. According to a second embodiment, it was possible to obtain hydrocyanic acid by ammoxidation of methanol, the methanol may have been obtained as described in the paragraph above titled "Valorisation of the biomass methanol".

The method of manufacturing HCN by ammoxidation of methanol:

CH ₃ OH + NH ₃ + O ₂ → HCN + 3H ₂ O

has been described in particular in the years 1950-1960 in the GB 718,112 and GB 913,836 patents of Distillers Company. It uses a catalyst based on molybdenum oxide at a temperature ranging from 340 ^° C. to 450 ^° C., or an antimony-tin catalyst at a temperature ranging from 350 ° C. to 600 ^° C. Reference can be made to Walter Sedriks 'article in Process Economics Reviews PEP' 76-3, June 1977. This process has been the subject of various improvements, in particular with regard to the catalytic systems used; mention may be made, for example, of systems based on silica-supported mixed molybdenum-iron oxides (US Pat. No. 3,911,089, US Pat. No. 4,511,548 to The Standard Company, JP 2002-097017 to Mitsubishi), Fe-based catalysts. -Sb-O described by Nitto Chemical Industry (EP 340 909, EP 404 529, EP 476 579, Science and Technology in Catalysis 1998, pages 335-338, Applied Catalysis A: General 194-195, 2000, 497-505) or by Mitsubishi (JP 2002-097015, JP 2002-097016, EP 832 877).

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, or bioressourcée, 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: l, 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 main forms: in mineral form, that is to say carbon dioxide (CO2), and in organic form, that is to say carbon incorporated into molecules organic.

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. The ¹⁴ C, it is radioactive (each gram of a living being contains enough ¹⁴ C isotopes to give 13.6 decays per minute) and the number of such atoms in a sample decreases over time (t) according to the law:

n = no exp (-at),

in which:

- no is the number of ¹⁴ C at the origin (on 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 ¹⁴ C content 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 since the extraction of materials. first renewable, until the manufacture of methyl methacrylate according to the invention and even until 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. Advantageously, methyl methacrylate obtained by the process according to the invention contains 0,2xl0 ^{~ 10%} when, 2xlθ ^{~ 10%} by weight of ¹⁴ C on the total weight of carbon. In a preferred embodiment of the invention, the methyl methacrylate obtained according to the invention contains 100% of organic carbon derived from renewable raw materials and therefore l, 2xlθ ^{~ 10} % by mass of ¹⁴ C on 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. 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 to graphite or gaseous CO2, analyzed in a mass spectrometer. This technique uses an accelerator and a mass spectrometer to separate ¹⁴ C ions and 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 (including 7026-04) standards. 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 methyl methacrylate obtained according to the process according to the invention constitutes a raw material containing mainly methyl methacrylate, in the sense that the product resulting from the process may comprise impurities related to the nature of the reagents used or generated during the course of the process. process, which may be different impurities generated during the implementation of reagents of fossil origin. The method according to the invention may therefore further comprise one or more purification steps.

The methyl methacrylate obtained according to the process according to the invention can be used as it is or optionally after a purification step, as a raw material in all the applications in which it is known to use MAM, in particular as a monomer for the manufacture of poly (methyl methacrylate), as a starting material for the organic synthesis of higher methacrylates, as a 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 an additive for lubricants.

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 Synthetic Gas CO / H ₂ and Isolation of Carbon Monoxide

In the process of synthesis of methyl formate by carbonylation of methanol, it is not necessary to look for high purities of carbon monoxide, and in particular it is possible to have residual nitrogen because the pressures at which the process is implemented are relatively weak. However any inert impurity such as nitrogen or argon, which can not be consumed by the reaction, will gradually contribute to a dilution of the CO. Although nitrogen and argon are not not harmful chemically in the process, it is therefore preferable to limit as much as possible the content of these impurities.

The pressure at which carbon monoxide is subsequently used is also relatively low, however the purification treatments leading to pressure losses, it is preferable to operate the gasification of the biomass under pressure.

In the present example, an ethanol-water mixture is used, the ethanol being obtained by ethanol fermentation of sugar. The reaction is carried out at 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 gases The products 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 Methyl Formate

Methyl formate is obtained by reaction of methanol and carbon monoxide in a 200 ml autoclave, with sodium methoxide as a catalyst.

In a 200 ml autoclave, 32 g of methanol obtained in Example 2 are placed at a temperature of 80 ^° C. with stirring and 60 bar of CO, the CO being obtained as in Example 1, after 3 hours. By maintaining the pressure of CO, a yield of methyl formate of 67% is obtained.

Example 4 Manufacture of Acetone from Wheat Straw by Enzymatic Hydrolysis followed by Aceto-Butyl Fermentation

It was carried out as described in the Review of the French Petroleum Institute, Vol 36, No. 3, May-June 1981, pages 339-347. In a shredder, wheat straw was shredded and the shredded straw was crushed in a hammer mill. It was followed by acid treatment at a low concentration at a temperature of 100 ° C for about 1 hour. After neutralization of the acid, the medium was brought back to the pH of about 5 which is required by the enzymatic hydrolysis. A cellulase solution was prepared in the presence of nutrients in serial fermentors, the culture of the Trichoderma microorganism being carried out in the first fermenters from previously milled straw, and the cellulose being produced in the following fermenters. From the contents of the last fermenter, the desired enzymatic solution was separated by centrifugation and filtration.

Enzymatic hydrolysis of straw pretreated above by enzymatic solution above was carried out in series-connected reactors.

After filtration, solutions of sugars in Ce and C ₅ were collected. The filtrate which contains lignin was dried as a fuel. Aceto-butyl fermentation of the above C ₆ and C ₅ sugar solutions was conducted using the microorganism Clostridium acetobutylicum under aseptic conditions.

The fermentation comprises two successive phases, the first leading to the production of acetic and butyl acids and the second to the production of acetone, butanol and ethanol in the following proportions by weight: butanol 68%; acetone 29%; and ethanol 3%.

The acetone was separated by azeotropic distillation.

Example 5 Synthesis of acetone cyanohydrin

For this batch synthesis, a 1-liter jacketed glass reactor equipped with mechanical stirring and surmounted by a refrigerant is used. The temperature is controlled via a circulation of cold brine in the double jacket (cryostat). In the previously cooled reactor (approximately

0 ⁰ C), 69.5 g of pure HCN and 149.4 g of acetone previously obtained by fermentation according to Example 4 are introduced.

(equimolar mixture). As soon as the mixture reaches the temperature of 0 ^° C., 34 mg of the diethylamine (DEA) catalyst are introduced. The temperature goes through a maximum of

18 ° C in about 6 minutes and then quickly stabilizes towards

0 ° C. Manual samples are taken (about 1 g) over time to track the amount of unreacted HCN. The determination of free HCN is carried out according to the Charpentier-Volhard method based on the precipitation of cyanide ions CN ^" using a solution of nitrate of silver N / 10 in excess and titration of the excess nitrate of silver solution with a KSCN N / 10 solution in the presence of a Fe (SO ₄ ) 3 indicator in solution After 150 minutes of reaction, a mixture comprising 1.53% by weight of free HCN, ie 0.533 mol / 1, which is equivalent to 10.855 mol / l of converted HCN and a degree of conversion to acetone cyanohydrin of 95.32% The crude product is neutralized by adding excess sulfuric acid (neutralization of the basic catalyst) and then purified by distillation under vacuum Unconverted acetone and HCN are removed at the top (progressive vacuum of 760 to 30 mm Hg and maximum temperature of 100 ^° C.).

Example 6 Synthesis of acetone cyanohydrin

The preceding example is reproduced with 69.5 g of HCN resulting from the ammoxidation of methane from biogas and 149.4 g of acetone previously obtained by fermentation according to Example 4. The target reaction temperature is -15 ° C. ⁰ C (an exothermic peak at -9 ⁰ C is observed for 9 minutes of reaction). Free HCN monitoring is performed as in the previous example. After 340 minutes of reaction, a mixture comprising 1.20% by weight of free HCN is obtained, ie 0.418 mol / l, which is equivalent to 10.667 mol / l of converted HCN and a degree of conversion to acetone cyanohydrin of 96.23. %. After distillation of the reaction product according to the preceding example, purified acetone cyanohydrin is obtained at 99.0 - 99.5%.

Example 7 Manufacture of α-Hydroxyisobutyramide

50 g of MnO 2 with a particle size of 0.5 to 0.8 mm are placed in a tubular glass reactor with an internal diameter of 15 mm and a length of 450 mm. The reactor is heated to 60 ^° C. A solution containing 30% by weight of acetone cyanohydrin, 10% by weight of acetone, and 60% by weight of deionized water is fed to the reactor with a flow rate of 30 g / h. The reaction results in a yield of alpha-hydroxyisobutyramide of 86%.

Example 8: Manufacture of methyl alpha-hydroxyisobutyrate

In a quartz tube 15 mm in diameter and 300 mm long, 50 ml of glass beads approximately 1 mm in diameter are placed. The reactor is supplied with a solution of alpha-hydroxyisobutyramide obtained according to Example 7, methyl formate previously obtained according to Example 3, and methanol of Example 2 (molar ratios 1: 2: 3) with a flow rate of 17. g / hr by heating at 50 ^° C. Simultaneously a solution of 28% sodium methoxide in methanol is fed into the reactor with a flow rate of 0.5 g / hr. Products are condensed and analyzed by chromatography. A yield of methyl alpha-hydroxyisobutyrate of 49% is thus measured.

Example 9 Manufacture of Methyl Methacrylate

In this example, Zeolyst commercial zeolite, reference C8V100, having a lattice parameter of 2.655 nm is used as the catalyst. In a quartz tube with a diameter of 15 mm and a length of 450 mm, 10 g of the granular shaped catalyst approximately 1 mm in diameter are placed. The catalyst is heated to 250 ⁰ C, then a 50% by weight solution of methyl alpha-hydroxyisobutyrate in methanol is sent into the reactor after being vaporized, with a flow rate of 10 g / h. The products are condensed and analyzed by chromatography, giving a yield of methyl methacrylate of 75%. The presence of methanol makes it possible to limit the hydrolysis reactions of the ester.

Claims

1 - Process for manufacturing methyl methacrylate by reacting alpha-hydroxyisobutyramide with methyl formate to give methyl alpha-hydroxyisobutyrate and formamide, the methyl alpha-hydroxyisobutyrate being dehydrated to methyl methacrylate, characterized in that at least a fraction of the methyl formate involved in this reaction and / or at least a fraction of the alpha-hydroxyisobutyramide involved in this reaction has been obtained by a reaction or a succession of reactions. from biomass.

2 - Process according to claim 1, characterized in that at least a fraction of methyl formate is obtained by carbonylation of methanol using carbon monoxide extracted from a synthesis gas composed essentially of carbon monoxide and hydrogen, at least a fraction of the synthesis gas has been obtained by gasification of any material of animal or vegetable origin or from the recovery of waste liquor and bleaching of the manufacture of cellulosic pulps.

3 - Process according to one of claims 1 and 2, characterized in that at least a fraction of the methyl formate is obtained by carbonylation of methanol, at least a fraction of the methanol having been obtained by pyrolysis of wood or by gasification of all materials of animal or vegetable origin leading to a synthesis gas consisting essentially of carbon monoxide and hydrogen, or by fermentation from crops of plants such as wheat, corn, sugar cane or the 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.

4 - Process according to one of claims 1 to 3, characterized in that at least a portion of the alpha-hydroxyisobutyramide is obtained by hydration of acetone-cyanohydrin, at least a portion of the acetone cyanohydrin which may have been obtained by reaction of acetone with hydrocyanic acid, at least a part of which may be derived from the recycling of formamide, at least one of acetone and hydrocyanic acid having been obtained by a reaction or a succession of reactions from the biomass.

5 - Process according to claim 4, characterized in that acetone is obtained by aceto-butyl fermentation of C ₆ and C ₅ sugars, resulting in an acetone-butanol mixture, where appropriate with ethanol. from which acetone has been separated, for example by distillation, or by membrane separation or separation on silicalite.

6 - Process according to claim 4, characterized in that the acetone was obtained by hydrothermal liquefaction at 573 K of sewage sludge to obtain a black water containing hydrocarbons, then catalytic cracking of said black water in a steam atmosphere on a zirconia or zirconia / alumina catalyst supported on an iron oxide, and then separating the acetone, for example by distillation, or by membrane separation or separation on silicalite. 7 - Process according to claim 4, characterized in that acetone is obtained by catalytic conversion of palm oil residues on a zirconia or zirconia / alumina catalyst supported on an iron oxide, and then separation of acetone for example by distillation, or by membrane separation or separation on silicalite.

8 - Process according to claim 4, characterized in that the hydrocyanic acid is obtained by ammoxidation of methane, the methane having been obtained by fermentation in the absence of oxygen of animal and / or vegetable organic matter, such as pig manure, household waste, industrial waste, leading to a biogas composed essentially of methane and carbon dioxide, the carbon dioxide having been removed by washing the biogas with a basic aqueous solution of sodium hydroxide, potassium hydroxide or amine, or by water under pressure, or by absorption in a solvent such as methanol.

9 - Process according to claim 4, characterized in that the hydrocyanic acid has been obtained by ammoxidation of methanol, the methanol having been obtained by pyrolysis of wood or by gasification of any material of animal origin and / or vegetable , leading to a synthesis gas composed 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 a fraction of the synthesis gas for preparing the methanol may also come from the recovery of waste liquor and bleaching of the manufacture of cellulosic pastes.

10 - Use of methyl methacrylate containing from 0.2xl0 ^"10 % to l, 2xl0 ^{" 10} % by weight of ¹⁴ C on the total mass of carbon produced by the process as defined in one of claims 1 to 9, as monomer for the manufacture of poly (methyl methacrylate), as a starting material for the organic synthesis of higher methacrylates, as a product falling within the scope of preparation of acrylic emulsions and acrylic resins, as additive for polyvinyl chloride, as comonomer in the manufacture of copolymers and as additive for lubricants.