CN105622315A

CN105622315A - Method for preparing low carbon olefins from wood chips

Info

Publication number: CN105622315A
Application number: CN201410589203.9A
Authority: CN
Inventors: 周丛; 王国清; 李蔚; 杜志国; 张永刚; 张兆斌
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2014-10-28
Filing date: 2014-10-28
Publication date: 2016-06-01
Anticipated expiration: 2034-10-28
Also published as: CN105622315B

Abstract

The invention discloses a method for preparing low carbon olefins from wood chips. The method comprises the following steps: carrying out a dehydration reaction on mixed C6 monosaccharide prepared from the wood chips in the presence of a first solvent and a dehydration catalyst, carrying out a self-condensing reaction on the above obtained hydration reaction product in the presence of a condensing catalyst, and carrying out a hydrogenation reaction on the obtained self-condensing reaction product in the presence of a third solvent and a hydrogenation catalyst; and cracking the above obtained hydrogenation reaction product. The method for preparing low carbon olefins from the wood chips allows the low carbon olefins to be prepared from the wood chips in a high efficiency manner, effectively improves the total yield of the low carbon olefins in a cracking furnace, improves the utilization rate and the utilization values of natural resources, and also effectively reduces requirements of production of the low carbon olefins on a petroleum raw material.

Description

A kind of method being prepared low-carbon alkene by wood flour

Technical field

The present invention relates to the preparation field of low-carbon alkene, in particular it relates to a kind of method being prepared low-carbon alkene by wood flour.

Background technology

Low-carbon alkene typically refers to the general name of the unsaturated hydrocarbon of carbon four and carbon less than four, mainly includes ethylene, propylene, isobutene., butadiene etc. and has the Organic Chemicals of high economic worth. Along with China's expanding economy, the demand of these Organic Chemicals increases year by year. Although the production scale of low-carbon alkene is also increasing year by year, but also cannot meet growing demand.

For a long time, low-carbon alkene product is prepared with Petroleum by China, along with the maximization of petroleum chemical enterprise's process units scale, the single disposal ability overlapping oil refining apparatus of China alreadys more than 10,000,000 tons/year, and the ethylene production capacity of matched ethylene unit has also reached 80��1,200,000 tons/year. But along with the minimizing day by day of fossil resources, the petrochemical industry production cost based on crude oil improves year by year. Therefore, in the urgent need to developing a kind of new raw material preparing low-carbon alkene and method.

Summary of the invention

In order to solve the nervous and lasting cost increase problem of raw materials requirement that existing petroleum base low-carbon alkene produces, the present invention proposes a kind of method being prepared low-carbon alkene by wood flour. The method can with wood flour for raw material, high efficiency prepared low-carbon alkene, can also be effectively improved the gross production rate of pyrolysis furnace low-carbon alkene simultaneously, effectively reduces the demand to petroleum in the production of low-carbon alkene.

The present inventor is surprised to find that after deliberation afterwards, 5 hydroxymethyl furfural (the 5-hydroxymethylfurfural obtained after the mixing six carbon monosaccharide obtained from wood flour are carried out dehydration in ionic liquid, HMF) can the effect of catalyst issue be conigenous condensation reaction generate 5, 5 '-dihydroxymethyl bran accidental cause (5, 5 '-di (hydroxymethyl) furoin, DHMF), again to 5, 5 '-dihydroxymethyl bran accidental cause carries out hydrogenation reaction can obtain the saturated straight chain alkane of C10-C12, finally the saturated straight chain alkane of C10-C12 is carried out steam cracking and can obtain low-carbon alkene. the mixing six carbon monosaccharide obtained from wood flour can be converted into low-carbon alkene by the method expeditiously, it is also possible to improve the gross production rate of pyrolysis furnace low-carbon alkene, and that effectively reduces low-carbon alkene produces the demand to petroleum, thus completing the present invention.

The invention provides a kind of method being prepared low-carbon alkene by wood flour, the method comprises the steps:

(1) under the existence of the first solvent and dehydration catalyst, the mixing six carbon monosaccharide prepared from wood flour is carried out dehydration;

(2) under the existence of condensation catalyst, the dehydration reaction product that step (1) obtains is carried out self-condensation reaction;

(3) under the existence of the 3rd solvent and hydrogenation catalyst, the self-condensation reaction product that step (2) obtains is carried out hydrogenation reaction;

(4) hydrogenation reaction product that step (3) obtains is cracked.

Provided by the invention prepared the method for low-carbon alkene by wood flour can with wood flour for raw material, high efficiency prepared low-carbon alkene, the gross production rate of pyrolysis furnace low-carbon alkene can also be effectively improved simultaneously, while improve the utilization rate to natural resources and value, also effectively reduce the demand to petroleum in the production of low-carbon alkene.

Other features and advantages of the present invention will be described in detail in detailed description of the invention part subsequently.

Detailed description of the invention

Hereinafter the specific embodiment of the present invention is described in detail. It should be appreciated that detailed description of the invention described herein is merely to illustrate and explains the present invention, it is not limited to the present invention.

The present invention provides a kind of method being prepared low-carbon alkene by wood flour, and the method comprises the steps:

(4) hydrogenation reaction product that step (3) obtains is cracked.

According to the present invention, in step (1), described wood flour can be selected from least one in Pinus koraiensis wood, kahikatea wood, Cortex Fraxini mandshuricae, birch, elm, basswood, Chinese catalpa ripple spinulose tree fern wooden, yellow, Cedrus deoclar (Roxb.) G. Don and Lignum seu Ramulus Cunninghamiae Lanceolatae. Described wood flour can for timber processing or the waste material produced during Furniture manufacturing, and it has renewable, environmental protection and the feature of distribution, wide material sources, can produce the mixing six carbon monosaccharide being main component with glucose after being degraded.

In step (1), may include that from the operation of wood flour preparation mixing six carbon monosaccharide and wood flour is degraded diluted acid. Preferably, described wood dust is broken to 10-60 order, it is preferable that after the granule of 20-40 order size, carry out degraded operation. Wherein, described diluted acid can be selected from least one in hydrochloric acid, sulphuric acid and phosphoric acid. The mass fraction of described diluted acid can be 0.1-20%, it is preferable that 0.2-5%. The consumption of described diluted acid can be the 5-70 mass % of wood flour, it is preferable that 10-60 mass %. The operating condition of described degraded includes temperature can be 60-180 DEG C, it is preferable that 80-120 DEG C, the time can be 1-60min, it is preferable that 10-30min. Generally, it is thus achieved that mixing six carbon monosaccharide with glucose for main component, usually, the content of glucose be not less than mixing six carbon monosaccharide total amounts 40 mass %, it is preferred to 40-60 mass %.

In step (1), described first solvent can be ionic liquid. Described ionic liquid can be selected from least one in 1-alkyl-3-Methylimidazole. chlorine, 1-alkyl-3-Methylimidazole. carboxylic acid and 1-alkyl-3-methylimidazolidinyl phosphate ester. Preferably, described ionic liquid at least one in 1-butyl-3-Methylimidazole. chlorine, 1-pi-allyl-3-Methylimidazole. chlorine, 1-pi-allyl-3-Methylimidazole. formic acid, 1-ethyl-3-methylimidazole methyl orthophosphoric acid and 1-ethyl-3-methylimidazole acetic acid.

In step (1), described dehydration catalyst can be selected from least one in mineral acid, organic acid and metal halide. Described mineral acid can be selected from least one in sulphuric acid, hydrochloric acid, nitric acid and phosphoric acid. Described organic acid can be selected from least one in acetic acid, propanoic acid, benzoic acid, benzenesulfonic acid, ethanedioic acid, maleic acid, phthalic acid and p-phthalic acid. Described metal halide can be selected from least one in the chloride of chromium, aluminum, sodium, ferrum, copper, vanadium, molybdenum, platinum, ruthenium and rhodium or bromide. Preferably, described dehydration catalyst at least one in sulphuric acid, hydrochloric acid, acetic acid, benzoic acid, benzenesulfonic acid, chromium dichloride, chromium trichloride, aluminum chloride, sodium chloride, ferric chloride, copper chloride, vanadium chloride, molybdenum chloride, platinous chloride, platinum tetrachloride, ruthenic chloride and radium chloride. The consumption that makes of described dehydration catalyst can for 0.01-10 mole of % of described six carbon monosaccharide, it is preferable that 1-8 mole of %.

In step (1), the condition of described dehydration includes temperature can be 50-200 DEG C, it is preferable that 70-180 DEG C, the time can be 0.5-10 hour, it is preferable that 2-6 hour. Described dehydration can carry out under agitation. After described dehydration terminates, the mixture that can obtain after dehydration obtains dehydration reaction product 5 hydroxymethyl furfural. The mode obtaining 5 hydroxymethyl furfural from the mixture obtained after described dehydration may include that addition water and organic solvent in the mixture after dehydration, and make the mixture after dehydration, water and organic solvent be sufficiently mixed, standing makes aqueous phase and organic solvent be separated again, and then concentration organic solvent obtains 5 hydroxymethyl furfural mutually afterwards. Described organic solvent can be selected from least one in dichloromethane, carbon tetrachloride, chloroform, petroleum ether, ether and hexamethylene.

According to the present invention, in step (2), described condensation catalyst can be organic nitrogen heterocycle carbine. Preferably, described condensation catalyst is selected from 1,3,4-tri-tert-1,2,4-triazole-5-Cabbeens, 1,3,4-triphenyl-1,2,4-triazole-5-Cabbeens and 1,3,4-tri-naphthyl-1, at least one in 2,4-triazole-5-Cabbeens. The consumption that makes of described condensation catalyst can for 0.01-10 mole of % of described dehydration reaction product (5 hydroxymethyl furfural), it is preferable that 1-5 mole of %.

In step (2), described self-condensation reaction can carry out when presence or absence the second solvent. Described second solvent can be selected from least one in oxolane, N,N-dimethylformamide, dimethyl sulfoxide and ionic liquid. Described ionic liquid is identical with above-mentioned.

In step (2), the condition of described self-condensation reaction includes temperature can be 30-200 DEG C, it is preferable that 50-120 DEG C, the time can be 0.1-10 hour, it is preferable that 0.5-5 hour. After described self-condensation reaction terminates, the mixture that can obtain after self-condensation reaction obtains self-condensation reaction product 5,5 '-dihydroxymethyl bran accidental cause. The mixture obtained after described self-condensation reaction obtains 5, the mode of 5 '-dihydroxymethyl bran accidental cause may include that and first the second solvent steamed (if any), then wash the solid obtained with hexamethylene, 5 can be obtained after drying, 5 '-dihydroxymethyl bran accidental cause.

According to the present invention, in step (3), the active component of described hydrogenation catalyst can be Metal Palladium and/or platinum. The carrier of described hydrogenation catalyst can be at least one in mineral acid and/or inorganic acid salt, acid organic salt, activated carbon and heteropoly acid and/or heteropolyacid salt. Described mineral acid can be selected from least one in sulphuric acid, hydrochloric acid, nitric acid and phosphoric acid. Described inorganic acid salt can be phosphoric acid tantalum and/or niobium phosphate. Described acid organic salt can be selected from [bmim]₃PW₁₂O₄₀��[MIMPS]₃PW₁₂O₄₀��[PyPS]₃PW₁₂O₄₀[TEAPS]₃PW₁₂O₄₀In at least one. Described heteropoly acid can be H₃PW₁₂O₄₀. Described heteropolyacid salt can be selected from CsH₂PW₁₂O₄₀��NaH₂PW₁₂O₄₀��LiH₂PW₁₂O₄₀And KH₂PW₁₂O₄₀In at least one. Preferably, described hydrogenation catalyst is selected from the mixture of the phosphoric acid mixture with palladium carbon and/or phosphoric acid tantalum and platinum carbon. Specifically, described hydrogenation catalyst can be selected from Pd/CH₃PO₄��Pt/CsH₂PW₁₂O₄₀��Pt/Cs_2.5H_0.5PW₁₂O₄₀And Pt/CTaOPO₄In at least one. The consumption of described hydrogenation catalyst can for 0.01-10% mole of % of described self-condensation reaction product (5,5 '-dihydroxymethyl bran accidental cause) with the gauge of using of active component, it is preferable that 0.1-5 mole of %.

In step (3), it can be 0.1-30MPa that the condition of described hydrogenation reaction includes pressure, it is preferable that 1-10MPa, temperature can be 25-350 DEG C, it is preferable that 50-300 DEG C, and the time can be 0.5-10 hour, it is preferable that 1-5 hour. Preferably, before carrying out described hydrogenation reaction, use the air in inert gas replacement reaction vessel. Described noble gas can be nitrogen and/or zero group gas. Described hydrogenation reaction can carry out under agitation.

In step (3), described 3rd solvent can be selected from least one in hydro carbons, alcohols and water. Described varsol can be selected from least one in ether, petroleum ether, dichloromethane, chloroform, heptane, hexane, Pentamethylene. and hexamethylene. Described alcohols solvent can be selected from least one in glycerol, ethanol and methanol. After described hydrogenation reaction terminates, the mixture that can obtain after hydrogenation reaction obtains the saturated straight chain alkane of C10-C12. The mode obtaining the saturated straight chain alkane of C10-C12 the mixture obtained after described hydrogenation reaction may include that the mixture filtration that will obtain after hydrogenated reaction, filters hydrogenation catalyst and reclaims, then removing the 3rd solvent.

According to the present invention, in step (4), described cracking can be steam cracking. Described steam cracking can carry out in steam cracking furnace. Preferably, described steam cracking furnace carries out the condition of described steam cracking to include the coil outlet temperature of steam cracking furnace and be 710-890 DEG C, preferred 780-860 DEG C, hydrogenation reaction product and the mass ratio of water vapour that step (3) obtains are 1:(0.3-1), it is preferable that 1:(0.4-0.8).

In step (4), low-carbon alkene can be obtained from pyrolysis product. The mode obtaining low-carbon alkene from described pyrolysis product can for operational approach commonly used in the art. Pyrolysis product such as can be easily separated by the described mode obtaining low-carbon alkene from pyrolysis product according to the flow process including following operation order: pyrolysis product isolates Pyrolysis fuel oil PFO and drippolene the acidic materials removing in cracking gas through oil scrubber and water scrubber, after compression, hydrogen and methane is isolated with domethanizing column, ethylene and propylene is isolated with dethanizer, ethylene and propylene is isolated with depropanizing tower, isolate carbon four component with debutanizing tower, obtain corresponding low-carbon alkene by separating each component obtained respectively through rectifying column separation.

Hereinafter will be described the present invention by specific embodiment.

In following example and comparative example:

In step (1), the computational methods of the yield mixing six carbon monosaccharide (total monosaccharide) are as follows:

In step (1), the computational methods of the yield of HMF are as follows:

In step (2), the computational methods of the yield of DHMF are as follows:

The computational methods of the yield of the saturated straight chain alkane of the C10-C12 that step (3) obtains are as follows:

In step (4), the computational methods of the yield of each pyrolysis product are as follows:

Embodiment 1

(1) by pick up from Furniture Factory with Lignum seu Ramulus Cunninghamiae Lanceolatae sawdust be main component the wood flour of 20-40 order that obtains after sieving of wood flour put in micro-wave diminishing pot, then in micro-wave diminishing pot, add the dilute hydrochloric acid that mass fraction is 0.4% accounting for wood flour 45 mass %. Opening microwave source, the power setting microwave source is heated as 3kw, question response liquid temp reach 100 DEG C after stirring reaction 20 minutes, it is thus achieved that containing the solution mixing six carbon monosaccharide. Undertaken the solution mixing six carbon monosaccharide concentrating, crystallization, filtration and dried obtain mixing six carbon monosaccharide, the yield recording mixing six carbon monosaccharide (total monosaccharide) is 39.45%.

Concentrated sulphuric acid (as catalyst) and the mixing six carbon monosaccharide obtained by said method that 1-butyl-3-Methylimidazole. chlorine (as solvent), mass fraction are 98% are added (wherein in concentrated sulphuric acid, the content of sulphuric acid is 0.5 mole of % of mixing six carbon monosaccharide) in stirred tank, then under agitation, react 3 hours at 80 DEG C; Take out the material obtained, add water and dichloromethane and make the material obtained, water and dichloromethane be sufficiently mixed, stand again and make aqueous phase and organic solvent phase (dichloromethane phase) separate, concentration organic solvent obtains 5 hydroxymethyl furfural (HMF) mutually afterwards, in aqueous phase, add methanol, make unreacted sugar precipitate out. Being computed, the yield of HMF is 82%.

(2) using oxolane (as solvent), 1,3,4-tri-tert-1, HMF that 2,4-triazoles-5-Cabbeen (as catalyst) and step (1) obtain adds in stirred tank (wherein 1,3,4-tri-tert-1, consumption is HMF 1.0 moles of % of 2,4-triazole-5-Cabbeens), then under agitation, react 1 hour at 80 DEG C; Take out the material obtained, the solid obtained with hexamethylene washing again after oxolane is evaporated off, obtain 5 then through dried, 5 '-dihydroxymethyl bran accidental cause (DHMF). Being computed, the yield of DHMF is 89%.

(3) using methanol (as solvent), Pd/CH₃PO₄The DHMF that (as catalyst) and step (2) obtain adds (wherein Pd/CH in autoclave pressure₃PO₄The 3.2 moles of % being DHMF with the Pd consumption counted), then replace the air in autoclave pressure with argon, then be filled with hydrogen in autoclave pressure, make the pressure in autoclave pressure reach 3.45MPa, then under agitation, react 6 hours at 200 DEG C; Take out the material that obtains, through the saturated straight chain paraffins mixture of Filtration of catalyst and the C10-C12 obtaining oily after solvent is distilled off. The content of C10 alkane in the saturated straight chain paraffins mixture of the C10-C12 of this oily obtained through chromatograph and mass spectral analysis, the content of C11 alkane, the content of C12 alkane, total alkane content in Table 1.

(4) the saturated straight chain paraffins mixture of C10-C12 steam and step (3) obtained injects in small-sized cracking analog (purchased from Sinopec Beijing Research Institute of Chemical Industry) according to the ratio that mass ratio is 1:0.5 and carries out steam cracking reaction, and the coil outlet temperature at small-sized cracking analog is maintain reaction 40 minutes at 790 DEG C. By the low-carbon alkene composition in the gas-phase product that chromatograph detection reaction obtains, and calculate the yield of each pyrolysis product. The yield of each pyrolysis product is in Table 2.

Embodiment 2

Outside divided by lower operating condition, other are all identical with embodiment 1.

In step (1), the first solvent changing 1-pi-allyl-3-Methylimidazole. chlorine into, dehydration catalyst changes chromium dichloride into, and reaction temperature changes 100 DEG C into.

In step (2), not using the second solvent, condensation catalyst changes into 1,3,4-triphenyl-1 simultaneously, 2,4-triazole-5-Cabbeens, reaction temperature changes 60 DEG C into.

The yield of HMF, the yield of DHMF, the content of C10 alkane in the saturated straight chain paraffins mixture of C10-C12, the content of C11 alkane, the content of C12 alkane, total alkane content in Table 1.

The composition of the final low-carbon alkene obtained and the yield of each pyrolysis product are in Table 2.

Embodiment 3

In step (1), the first solvent changing 1-pi-allyl-3-Methylimidazole. formic acid into, dehydration catalyst changes chromium trichloride into, and reaction temperature changes 120 DEG C into.

In step (3), change hydrogenation catalyst into Pt/CsH₂PW₁₂O₄₀, reaction temperature changes 250 DEG C into, and the pressure in autoclave pressure changes 3.20MPa into.

In step (4), the mass ratio of the saturated straight chain paraffins mixture of C10-C12 steam and step (3) obtained changes 1:0.6 into, changes the coil outlet temperature of small-sized cracking analog into 820 DEG C.

Embodiment 4

In step (1), the first solvent changing 1-ethyl-3-methylimidazole methyl orthophosphoric acid into, dehydration catalyst changes aluminum chloride into, and reaction temperature changes 180 DEG C into.

In step (2), the second solvent changing 1-ethyl-3-methylimidazole acetic acid into, condensation catalyst changes 1,3,4-tri-naphthyl-1 into, and 2,4-triazole-5-Cabbeens, reaction temperature changes 100 DEG C into.

In step (3), change hydrogenation catalyst into Pt/CsH₂PW₁₂O₄₀, reaction temperature changes 300 DEG C into, and the pressure in autoclave pressure changes 5.00MPa into.

Embodiment 5

In step (3), change hydrogenation catalyst into Pt/CTaOPO₄, the 3rd solvent changes water into, and reaction temperature changes 300 DEG C into, and the pressure in autoclave pressure changes 3.45MPa into.

In step (4), the mass ratio of the saturated straight chain paraffins mixture of C10-C12 steam and step (3) obtained changes 1:0.7 into, changes the coil outlet temperature of small-sized cracking analog into 850 DEG C.

Embodiment 6

Embodiment 7

Outside divided by lower operating condition, other are all identical with embodiment 6.

In step (1), by pick up from Furniture Factory with Lignum seu Ramulus Cunninghamiae Lanceolatae sawdust be main component wood flour change into and mixed six carbon monosaccharide by Pinus koraiensis wood, kahikatea wood, the wood flour mixture that form of Cortex Fraxini mandshuricae prepare, finally recording the yield mixing six carbon monosaccharide is 37.51%; Dehydration catalyst changes molybdenum chloride into, and reaction temperature changes 80 DEG C into.

Embodiment 8

In step (1), by pick up from Furniture Factory with Lignum seu Ramulus Cunninghamiae Lanceolatae sawdust be main component wood flour change the wood flour mixture that is made up of birch, elm, basswood, Chinese catalpa ripple spinulose tree fern wooden, yellow, Cedrus deoclar (Roxb.) G. Don and Lignum seu Ramulus Cunninghamiae Lanceolatae into prepare mixing six carbon monosaccharide, the yield finally recording mixing six carbon monosaccharide is 40.52%; Dehydration catalyst changes platinum tetrachloride into, and reaction temperature changes 120 DEG C into.

Comparative example 1

Steam cracking reaction is carried out according to the operational approach of embodiment 1 step (4) by having the Petroleum of physical property shown in table 3.

Table 1

	HMF yield	DHMF yield	C10 yield	C11 yield	C12 yield	Total alkane yield
							Embodiment 1	82%	89%	18.6%	37.6%	32.2%	88.4%
Embodiment 2	80%	99%	18.6%	37.6%	32.2%	88.4%
							Embodiment 3	81%	99%	-	24.3%	67.6%	91.9%
Embodiment 4	79%	91%	4.3%	36.8%	38.6%	79.7%
							Embodiment 5	82%	91%	27.0%	22.9%	45.6%	95.5%
Embodiment 6	82%	99%	27.0%	22.9%	45.6%	95.5%
							Embodiment 7	79%	99%	27.0%	22.9%	45.6%	95.5%
Embodiment 8	78%	99%	27.0%	22.9%	45.6%	95.5%

In table 2, low-carbon alkene total recovery refers to the total recovery of ethylene, propylene, butylene and butadiene.

Table 2

	Hydrogen yield	Yield of ethene	Propene yield	Butylene yield	Butadiene yield	Low-carbon alkene total recovery
							Embodiment 1	0.40%	33.65%	18.25%	6.52%	5.03%	63.45%
Embodiment 2	0.40%	33.65%	18.25%	6.52%	5.03%	63.45%
							Embodiment 3	0.61%	38.91%	18.55%	5.16%	5.84%	68.46%
Embodiment 4	0.61%	38.91%	18.55%	5.16%	5.84%	68.46%
							Embodiment 5	0.71%	42.82%	16.95%	3.47%	5.83%	69.07%
Embodiment 6	0.71%	42.82%	16.95%	3.47%	5.83%	69.07%
							Embodiment 7	0.71%	42.82%	16.95%	3.47%	5.83%	69.07%
Embodiment 8	0.71%	42.82%	16.95%	3.47%	5.83%	69.07%
							Comparative example 1	0.83%	29.30%	16.38%	4.84%	4.60%	55.12%

In table 3, in Petroleum, the content of each component is weight/mass percentage composition, and unit is " quality % ".

Table 3

N-alkane	Isoparaffin	Cycloalkane	Alkene	Aromatic hydrocarbons	Hydrocarbon more than C12	Other impurity
							37.83	35.23	16.16	0.10	10.33	0.32	0.03

As can be seen from Table 1, use provided by the invention by wood flour prepare low-carbon alkene method can high efficiency from wood flour prepare mixing six carbon monosaccharide, simultaneously high efficiency change into HMF by mixing six carbon monosaccharide, DHMF is changed into by high efficiency for HMF, and further, by DHMF is carried out hydrogenation reaction, it is possible to the saturated straight chain alkane obtaining C10-C12 of high yield.

From table 2 it can be seen that compared with comparative example 1, use and provided by the invention prepared the method for low-carbon alkene by wood flour and can obtain higher low-carbon alkene total recovery. Meanwhile, the yield of the ethylene and butadiene that have essential industry using value in embodiment 1-8 is significantly higher than comparative example 1.

Claims

1. the method being prepared low-carbon alkene by wood flour, it is characterised in that the method comprises the steps:

(4) hydrogenation reaction product that step (3) obtains is cracked.

2. method according to claim 1, wherein, in step (1), described wood flour is at least one in Pinus koraiensis wood, kahikatea wood, Cortex Fraxini mandshuricae, birch, elm, basswood, Chinese catalpa ripple spinulose tree fern wooden, yellow, Cedrus deoclar (Roxb.) G. Don and Lignum seu Ramulus Cunninghamiae Lanceolatae;

Preferably, include diluted acid, degrade wood flour from the operation of wood flour preparation mixing six carbon monosaccharide;

Preferably, described diluted acid at least one in hydrochloric acid, sulphuric acid and phosphoric acid;

Preferably, the operating condition of described degraded includes temperature and is 60-180 DEG C, it is preferable that 80-120 DEG C, the time is 1-60min, it is preferable that 10-30min.

3. method according to claim 1 and 2, wherein, in step (1), described first solvent is ionic liquid;

Preferably, described ionic liquid at least one in 1-alkyl-3-Methylimidazole. chlorine, 1-alkyl-3-Methylimidazole. carboxylic acid and 1-alkyl-3-methylimidazolidinyl phosphate ester;

It is further preferred that at least one that described ionic liquid is in 1-butyl-3-Methylimidazole. chlorine, 1-pi-allyl-3-Methylimidazole. chlorine, 1-pi-allyl-3-Methylimidazole. formic acid, 1-ethyl-3-methylimidazole methyl orthophosphoric acid and 1-ethyl-3-methylimidazole acetic acid.

4. method according to claim 1 and 2, wherein, in step (1), described dehydration catalyst at least one in mineral acid, organic acid and metal halide;

Preferably, described dehydration catalyst at least one in sulphuric acid, hydrochloric acid, acetic acid, benzoic acid, benzenesulfonic acid, chromium dichloride, chromium trichloride, aluminum chloride, sodium chloride, ferric chloride, copper chloride, vanadium chloride, molybdenum chloride, platinous chloride, platinum tetrachloride, ruthenic chloride and radium chloride.

5. method according to claim 4, wherein, in step (1), the 0.01-10 mole of % making consumption be described six carbon monosaccharide of described dehydration catalyst, it is preferable that 1-8 mole of %.

6. method according to claim 1 and 2, wherein, in step (1), the condition of described dehydration includes temperature and is 50-200 DEG C, it is preferable that 70-180 DEG C, and the time is 0.5-10 hour, it is preferable that 2-6 hour.

7. method according to claim 1 and 2, wherein, in step (2), described condensation catalyst is organic nitrogen heterocycle carbine;

Preferably, described condensation catalyst is selected from 1,3,4-tri-tert-1,2,4-triazole-5-Cabbeens, 1,3,4-triphenyl-1,2,4-triazole-5-Cabbeens and 1,3,4-tri-naphthyl-1, at least one in 2,4-triazole-5-Cabbeens.

8. method according to claim 7, wherein, in step (2), the 0.01-10 mole of % making consumption be described dehydration reaction product of described condensation catalyst, it is preferable that 1-5 mole of %.

9. method according to claim 1 and 2, wherein, in step (2), described self-condensation reaction carries out when presence or absence the second solvent;

Preferably, when described self-condensation reaction carries out when there is the second solvent, described second solvent at least one in oxolane, DMF, dimethyl sulfoxide and ionic liquid.

10. method according to claim 1 and 2, wherein, in step (2), the condition of described self-condensation reaction includes temperature and is 30-200 DEG C, it is preferable that 50-120 DEG C, and the time is 0.1-10 hour, it is preferable that 0.5-5 hour.

11. method according to claim 1 and 2, wherein, in step (3), the active component of described hydrogenation catalyst is Metal Palladium and/or platinum.

12. method according to claim 11, wherein, the carrier of described hydrogenation catalyst is at least one in mineral acid and/or inorganic acid salt, acid organic salt, activated carbon and heteropoly acid and/or heteropolyacid salt;

Preferably, described mineral acid at least one in sulphuric acid, hydrochloric acid, nitric acid and phosphoric acid;

Preferably, described inorganic acid salt is phosphoric acid tantalum and/or niobium phosphate;

Preferably, described acid organic salt is selected from [bmim]₃PW₁₂O₄₀��[MIMPS]₃PW₁₂O₄₀��[PyPS]₃PW₁₂O₄₀[TEAPS]₃PW₁₂O₄₀In at least one;

Preferably, described heteropoly acid is H₃PW₁₂O₄₀;

Preferably, described heteropolyacid salt is selected from CsH₂PW₁₂O₄₀��NaH₂PW₁₂O₄₀��LiH₂PW₁₂O₄₀And KH₂PW₁₂O₄₀In at least one.

13. method according to claim 12, wherein, described hydrogenation catalyst is selected from the mixture of the phosphoric acid mixture with palladium carbon and/or phosphoric acid tantalum and platinum carbon;

Preferably, described hydrogenation catalyst is selected from Pd/CH₃PO₄��Pt/CsH₂PW₁₂O₄₀��Pt/Cs_2.5H_0.5PW₁₂O₄₀And Pt/CTaOPO₄In at least one.

14. the method according to claim 12 or 13, wherein, in step (3), the consumption of described hydrogenation catalyst is calculated as 0.01-10% mole of % of described self-condensation reaction product with the consumption of active component, it is preferable that 0.1-5 mole of %.

15. method according to claim 1 and 2, wherein, in step (3), it is 0.1-30MPa that the condition of described hydrogenation reaction includes pressure, it is preferable that 1-10MPa, and temperature is 25-350 DEG C, preferred 50-300 DEG C, the time is 0.5-10 hour, it is preferable that 1-5 hour.

16. method according to claim 1 and 2, wherein, in step (3), described 3rd solvent at least one in hydro carbons, alcohols and water;

Preferably, described varsol at least one in ether, petroleum ether, dichloromethane, chloroform, heptane, hexane, Pentamethylene. and hexamethylene;

Preferably, described alcohols solvent at least one in glycerol, ethanol and methanol.

17. method according to claim 1 and 2, wherein, in step (4), described in be cracked into steam cracking;

Preferably, described steam cracking carries out in steam cracking furnace;

Further preferably, described steam cracking furnace carries out the condition of described steam cracking include the coil outlet temperature of steam cracking furnace and be 710-890 DEG C, preferred 780-860 DEG C, hydrogenation reaction product and the mass ratio of water vapour that step (3) obtains are 1:(0.3-1), it is preferable that 1:(0.4-0.8).