WO2010082075A1

WO2010082075A1 - Biocell - liquid biofuel consisting of isomers of methylpyran and methyltetrahydropyran and a process for obtaing it from cellulose in a one step reaction

Info

Publication number: WO2010082075A1
Application number: PCT/IB2009/000051
Authority: WO
Inventors: Pedro Correia
Original assignee: Inventus, Produtos Quimicos Lda
Priority date: 2009-01-14
Filing date: 2009-01-14
Publication date: 2010-07-22

Abstract

Liquid biofuels consisting of isomers of methylpyran and methyl tetrahydropyran obtained from cellulose, hemicelluloses or starch, and a processs to obtain it using ionic liquids as solvents and an hydrogenation catalyst in a one step reaction. The reversible equilibrium in reactions of hydrolysis of cellulose into oligomers of glucose and glucose itself, the contrary reactions of condensation of glucose into oligomers by a intermolecular dehydration, and the intramolecular dehydration of glucose into isomers of hydroxymethylpyranone (HMP) is displaced in the direction of HMP, by making HMP to disappear. This elimination of HMP is not effectively achieved by extraction or destilation as previously reported, but by hydrogenation to products which are no more submitted to hydration or oligomerisation. This hydrogenation takes place in the same reaction mixture as the hydrolysis, condensation and dehydration reactions. By GCMS only one relevant product was obtained representing about 90% of final products. It was identified by NMR as 2 - methyl pyran.

Description

Biocell - Liquid biofuell consisting of isomers of methylpyran and methyl tetrahydropyran and a process for obtaining it from cellulose in a one step reaction

Description

1 . Field of invention

Liquid biofuels from cellulose, ionic liquids, renewable energy, hydrogenation in ionic liquids

2 . Background of the invention

The world production of cellulose on land is 40 billion ton per year and the stock of cellulose is 700 billion ton..

The world consumption of fossil fuels is 8 billion ton per year.

The food production in the world is 3 billion ton per year.

From these 3 numbers we conclude that to take out from food .materials to produce bio ethanol or vegetable oils for biodiesel would not solve the problem of substituting fossil fuels, and would cause hunger.

On the other side, there are large surfaces of arable land, which are not cultivated or which produce plants not suitable for food. In these surfaces, the production of cellulose from trees or bush is possible. On the other side, cellulose containing biomass is a side product of many food crops.

One of the crops which produce large quantities of cellulose is sugar cane, which has an yield of 80 ton per hectar, In one ton of sugar cane there are about 80 kg of sugar, which may be converted to 50 kg of bioethanol. Besides sugar there are 250 kg of cellulose and hemicellulose, which is a much bigger quantity than sugar, which is not converted to liquid fuels. There are also about

80 kg lignin, which may become a useful energy source in the conversion of cellulose in liquid biofuels.

Cellulose, hemicellulose and starch have been studied in the past as possible sources of raw materials for liquid fuels and chemicals.

Wood itself is since thousands of years an energy source. Biomass is used today to produce electricity, but electricity represents only 10% of the consumption of fossil fuels. It is therefore important to find a process to convert cellulose in liquid fuels, suitable for energy supply to transportation and industry, which represent 90% of the consumption of fossil fuels.

The substitution of fossil fuels is also important because of the carbon dioxyde which they produce by burning. Although cellulose also produces carbon dioxide by burning, the same quantity of carbon dioxide was taken out of the atmosphere by photosynthesis to produce cellulose.

Although the carbon dioxide content on earth was up to 6000 ppm 100 million years ago, it decreased to 250 ppm in the nineteen century and increased again up to 380 ppm. These sharp increase in the last century is caused by burning fossil fuels and causes dramatic climate changes due to the greenhouse effect.

As a consequence, to convert cellulose into a liquid fuel is since decades a challenge for scientists, because the existing cars and trucks could drive with such a liquid biofuel without major changes in the motor.

The exhausting oil reserves and the political dependence on unstable countries producing oil is also a major problem today.

Producing electricity from nuclear or from renewable sources like wind, waves, rivers or photovoltaic, is used today, but represents only 20-30% of electricity production. The rest is produced from fossil fuels.

The substitution of liquid fuels by electricity creates a major problem of storage and transportation of electricity, which is technically possible, but far more expensive than the cellulose biofuels (Biocell) .

Because cellulose is renewable, abundant and not producing carbon dioxide by burning if photosynthesis is considered, there has been recent scientific work on following subjects (Bibliography 1 to 9):

- dissolution of cellulose in ionic liquids instead of traditional processes using water and organic solvents

- hydrolysis of cellulose in ionic liquids

- dehydration of fructose in ionic liquids to hydroxyl methyl furfural

- hydrogenation in organic solvents of hydroxymethyl furfural to isomers of dimethyl tetrahydrofuran

- isomerisation of glucose to fructose

2 . Detailed description of the invention From our previous work (PCT WO 2008 053284 and PCT IB 2008 03313 ) we found that the hydrolysis of cellulose to glucose in N methyl imidazol chloride

(MIC) was always followed by dehydration of glucose and the production of oligomers of glucose both by incomplete hydrolysis of cellulose and by intermolecular dehydration of glucose.

We further found that the conversion of cellulose to dehydration products of glucose was limited by the reversibility of the mentioned reactions.

After the hydrolysis of cellulose in MIC, always an important quantity of cellulose was not hydrolysed. Only a small concentration of HMP was formed in the reversible equilibrium, which we could extract with suitable solvents.

However, in industry it would be very costly to make the hydrolysis of cellulose to proceed by removing HMP by solvent extraction.

The hydrogenation of HMP in MIC using current catalysts for hydrogenation like

Pd or Pt on activated carbon or copper chromite was not possible because of deactivation of the catalyst by chloride ions.

HMP itself can not be used as a liquid biofuel, because it is solid and unstable.

In the literature there are many descriptions of hydrogenations in ionic liquids containing N methyl imidazol, which refer as anion hydrogenosulphate, hexafluorphosphorous and tetrafluorboron. The fluorinated anions are unstable in contact with the water, as contained in our reaction mixture.

Therefore we made an experiment with the ionic liquid N methyl imidazol hydrogenosulphate and found that the reversible reaction were all displaced as long as HMP was hydrogenated and by this way disappeared from the reversible reaction system.

The separation of the hydrogenation products of HMP was stratghtforward both by destilation or by solvent extraction. The distillation is the simplest way, considering that methyl pyran has a boiling point around 8O⁰C while this ionic liquid has a boiling point above 200⁰C, with decomposition. .

In the final reaction mixture after hydrogenation, no cellulose precipitated after dilution 1 g of this mixture in 50 g of water. A clear colourless liquid was obtained.

Example

In a stirred glass 250 ml reactor we introduced

N methyl imidazol 126 g

We added slowly

Sulphuric acid 98% 150 g

Water 1Og

Cellulose 1O g and heated 30 minutes under stirring at 8O⁰C until formation of a slurry..

This mixture was introduced in a Parr reactor, which was inertised 5 times with nitrogen, and heated during 3 hours at 9O⁰C with a hydrogen pressure of 30 bar, The pressure was maintained by introducing more hydrogen as long as the pressure was lower than 30 bar.

The reaction mixture was cooled and destilled. The water which destilled was separated from the organic layer by decantation. A sample of the extract was injected in a GCMS and submitted to NMR. . An yield of 91 % was found, considering that according to stoechiometry 100 g cellulose give 56 g of methyl pyran.

Bibliography

1 . Jaroslaw Lewkowski, Synthesis, Chemistry and Applications of 5- Hydroxymethyl - furfural and its derivatives, , Arkivoc, 2001 , 17-54

2 . Claude Moreau, Annie Finiels, Laurent Vanoye, Dehydration of fructose and sucrose into 5-hydroxymethylfurfural in the presence of 1-H-3-methyl imidazolium chloride acting both as solvent and catalyst, , journal of Molecular Catalysis A, 2006, 165-169

3 . Fred Shafizedh, Saccharification of lignocellulosic materials, Pure and Appl. Chem., vol 55, No 4, pp 705 - 720, 1983

4 . Khavinet Lourvanij and Gregory Rorrer, Reaction rates for the partial dehydration of glucose to organic acids in solid-acid molecular sieving catalyst powders J. Chem. Tech. Biotechnol., 1997, 69, 35 - 44

5 . Yuri Roman Leshkov, Christopher Barrett, Zehn Y. Liu, James A. Dumesic, Production of dimethylfuran for liquid fuels from biomass derived carbohydrates, Nature, VoI 447, 21 June 2007, 982

6 . Acid in ionic liquid: an efficient system for hydrolysis of lignincellulose, Changzhi Li et al. Green Chemistry, 17^th December 2007

7 . Cataklytic conversion of cellulose into Sugar alcohols Atsushi Fukuoka et al. Angewandte Chemie, 2006 , 45, 5161-5163

8 . Pyranone by pyrolysis of cellulose, Fred Shafizadeh, Pure & Appliedd Chem, 1983, 55-4, 705-720

9 . Dissolution of cellulose with ionic liquids and its application- a minireview, Shengdong Zhu et al, Green Chemistry , 2006, 8 , 325 - 327

10 . WO 2008/053284 A1 - Liquid biofuels containing dihydroxymethyl furan, Pedro Correia, priority date 9 March 2007.

Claims

1 . Biofuels derived from cellulose, hemicellulose or starch (Biocell - EU registered trade mark) consisting of methyl pyran or methyl tetrahydropyran, its isomers, its cracking products caused by further hydrogenation, which can be used pure or mixed with gasoline as a liquid fuel .

2 . Process to produce biofuels of claim 1 consisting in a single step which includes the dissolution and hydrolysis of cellulose to obtain glucose, dehydration of glucose to hydroxymethyl pyranone and its isomers, hydrogenation of hydroxy methyl pyranone and its isomers using as a solvent an ionic liquid, for example N.-methylimidazole hydrogeno sulphate, containing a small quantity of water to make hydrolysis of cellulose possible, and applying a pressure of 2 - 100 bar of hydrogene and a temperature of 50 - 15O⁰C using as a catalyst palladium or platin on activated carbon, copper chromite, molybdenium-nickel oxide, or cobalt-nickel oxide; after the optimized time of reaction, separation of methyl pyran , methyl tetrahydro pyran and isomers by destilation. Or solvent extraction.

3 . In the process of claim 2 where ionic liquid is a hydrogeno sulphate of N methyl imidazol, hydrogeno sulphate of N methyl pyrrolidine or these amines with alkyl groups substituting one or more hydrogen atoms,

4 . In the process of claim 2 where the reaction temperature is 50 - 15O⁰C, preferably 60 to 100⁰C and the concentration of cellulose in the reaction mixture is 1 - 20%

5 . In the process of claim 2 where the catalyst is palladium or platin on activated carbon, cooper chromite, molybdenium-nickel oxide, or cobalt-nickel oxide in a concentration of 0,01 to 5% of the reaction mixture,

6 . In the process of claim 2 where the reaction takes place discontinuously in a stirred tank reactor or continuously in a fixed bed catalyst reactor