CN101249454A

CN101249454A - Solid base catalyst and applications for preparing biological diesel oil

Info

Publication number: CN101249454A
Application number: CNA2008100352842A
Authority: CN
Inventors: 杨建国; 梁学正; 高珊; 权南南; 张敬; 鲍少华; 王箭; 何鸣元
Original assignee: East China Normal University
Current assignee: East China Normal University
Priority date: 2008-03-28
Filing date: 2008-03-28
Publication date: 2008-08-27

Abstract

The invention discloses a solid base catalyst and is application in biodiesel synthesis. The catalyst is prepared from organic metal salt and aluminium oxide or diatomite by grinding and mixing at room temperature, and calcining at high temperature. The biodiesel is synthesized by ester exchange, by adding grease, low carbon alcohol and the solid base catalyst into a three-necked container to heat for refluxing under stirring, filtering to obtain catalyst, demixing the filtrate to obtain lower layer glycerol and upper layer mixture, adding NaHCO3 solution into the upper layer mixture, washing until a neutral condition, drying with anhydrous MgSO4, and vacuum distilling. The catalyst for biodiesel synthesis has the advantages of high yield, cheap price, small consumption amount, mild reaction condition, short reaction time, repeated use of the catalyst, no environmental pollution and low requirement for raw material.

Description

Solid base catalyst and the application in the preparation biodiesel thereof

Technical field

The present invention relates to the organic chemistry synthesis technical field, specifically a kind of solid base catalyst and the application in the preparation biodiesel thereof.

Background technology

Along with the minimizing day by day of mineral resources such as oil with and ball border influence over the ground, the green renewable fuel resource of development of new becomes the problem of present extensive concern.Biodiesel is a kind of mono alkyl ester of LCFA, not sulfur-bearing and aromatic hydrocarbons, and the Cetane number height, and greasy property is good, is a kind of high-quality clean fuel.Simultaneously, biodiesel has the incomparable advantage of traditional fossil fuel, raw material is the grease of reproducible living beings, and the environmental friendliness of product own is biodegradable, the flash-point height, nontoxic, volatile organic matter (VOC) content is low, and calorific value height, burning are fully, need not change and the frequent engine that cleans, also be to make biodegradable fine chemical product raw material with high added value.The of paramount importance environmental protection effect of biodiesel is with a kind of indirect mode, passes through CO ₂Again change hydrocarbon into, make CO ₂Clean discharge capacity reduces greatly.Scientists thinks that after deliberation using the biomass material energy is that a kind of ratio increase forest reserves (absorbing as CO2) more have conduct and more effective strategy.The production method of biodiesel mainly is that the ester exchange reaction by vegetable oil or animal tallow and low-carbon alcohols prepares.Normally used catalyst mainly contains acid catalysis, base catalysis, enzymatic and supercritical methanol technology.Acid catalyzed process [Ono, Y.J.Catal, 2003,216 (1-2): 406] often adopts sulfuric acid etc., exists the consumption of alcohol big, causes product layering difficulty, reaction temperature height, shortcomings such as catalytic efficiency difference.Base catalysis [Sheng Mei etc., colleges and universities' Chemical Engineering journal, 2004; 18 (2): 231-236] homogeneous catalyst such as NaOH, KOH, the sodium methoxides etc. of adopting exist the ingredient requirement strictness more, need the harsh conditions of anhydrous anacidity; there is the saponification phenomenon simultaneously, shortcomings such as product post processing complexity.Enzymatic [Nie Kaili etc., biological processing, 2005,3 (1): 58-62] exists catalyst to cost an arm and a leg, easy inactivation, shortcomings such as reaction time length.Exist reaction temperature and pressure to surpass the critical-temperature and the critical pressure of methyl alcohol with overcritical on-catalytic method, production technology requires high to equipment.The synthetic of general load-type solid will comprise first water lytic activity component, floods then, then also will refilter or reduce pressure and steam this loaded down with trivial details process of moisture, and both time consumption and energy consumption had also been wasted a large amount of raw materials.

Summary of the invention

A kind of solid base catalyst that the objective of the invention is to provide at the deficiencies in the prior art, catalyst is used for the preparation of biodiesel simultaneously, its Preparation of catalysts is simple and easy to do, preparation biodiesel production rate height, and catalyst amount is little and reusable.

The concrete technical scheme that realizes the object of the invention is:

A kind of solid base catalyst, it is to be that high-temperature roasting made after presoma and carrier at room temperature carried out ground and mixed with the organic metal salt; The concrete practice is: presoma and carrier are placed mortar, and the quality of presoma is 1～12: 10 with the ratio of the quality of carrier, under room temperature, grind about 1～2h, and 300～1000 ℃ of following roasting 5～10h in the Muffle furnace then, promptly; Described organic metal salt is alkali metal formate, acetate, oxalates or citrate; Described carrier is aluminium oxide, calcium oxide, magnesia, zinc oxide, zirconia, active carbon, molecular sieve, diatomite, carclazyte, silica gel or boehmite.

The application of above-mentioned solid base catalyst in the preparation biodiesel, its biodiesel adopts ester-interchange method preparation, and concrete steps are: add grease, low-carbon alcohols, solid base catalyst and add hot reflux and stir 1～3h in the three neck containers that have electromagnetic agitation, thermometer, reflux condensing tube; Heating and temperature control is at 50～110 ℃; With reacted material filtering, leach catalyst and filtrate, filtrate is carried out separatory, tells lower floor's glycerine, and the adding mass fraction is 5～10% NaHCO in the mixture of upper strata ₃Solution, its addition are 2～6 times of upper strata mixture quality, and washing is removed unreacted free fatty to neutral, tells upper organic phase with separatory funnel again, with organic facies with anhydrous MgSO ₄Drying removes by filter drier, and decompression distillation obtains nearly light yellow opaque products and is biodiesel.

The mass ratio of described adding grease, low-carbon alcohols, solid base catalyst is 1: 0.1～0.5: 0.04～0.1.

Described grease is waste oil, the waste oil in vegetable fat, animal tallow or the production process.

Described low-carbon alcohols is methyl alcohol, ethanol, propyl alcohol or butanols.

After the present invention reacted end, the catalyst that leaches was reusable, and activity remains unchanged substantially, and reaction yield still can reach more than 94%.

The reaction expression that biodiesel of the present invention is synthesized is as follows:

Compare with background technology, advantage of the present invention is: it is simple that catalyst has preparation process, less cost of power; Catalyst to the synthetic advantage that has of biodiesel is: the productive rate height; Catalyst amount is little, the reaction condition gentleness, and the reaction time is short, and catalyst is reusable, does not have environmental pollution, and is lower to ingredient requirement.

The specific embodiment

Below will the present invention is further elaborated by specific embodiment:

Embodiment 1

The preparation of the 1st step solid base catalyst

6g potassium acetate and 10g aluminium oxide are placed mortar, under room temperature, grind about 1h, 500 ℃ of following roasting 5h in the Muffle furnace then, promptly.

The 2nd step ester exchange reaction

Having electromagnetic agitation, thermometer, adding 5g rapeseed oil, 1.5g methyl alcohol, the above-mentioned solid base catalyst of 0.1g add hot reflux and stir 2h in the 100mL three-necked bottle of reflux condensing tube, are heated to 90 ℃.

The separation of the 3rd step catalyst and the purifying of product

With reacted material filtering in the three-necked bottle, the catalyst that leaches can be directly used in down secondary response, and filtrate is carried out separatory and told lower floor's glycerine, and upper strata product adding mass fraction is 6% NaHCO ₃Solution 70ml washing to remove unreacted free fatty, is told upper organic phase with separatory funnel, with anhydrous MgSO again to neutral ₄Drying removes by filter drier, and decompression distillation obtains nearly light yellow opaque products and is biodiesel.Yield is 98.3%.

Embodiment 2-6

Except for the following differences, all the other are identical with embodiment 1, and in the process of preparation catalyst, the acetic acid first is pressed the consumption of table 1.

Table 1

Embodiment 7-15

Except for the following differences, all the other are identical with embodiment 1, adopt the carrier shown in the table 2 respectively.

Table 2

Embodiment 16-19

Except for the following differences, all the other are identical with embodiment 1, adopt the presoma shown in the table 3 respectively.

Table 3

Embodiment 20-24

Except for the following differences, all the other are identical with embodiment 1, adopt the bio-oil shown in the table 4 respectively.

Table 4

Embodiment 25-29

Except for the following differences, all the other are identical with embodiment 1, adopt the low-carbon alcohols shown in the table 5 respectively.

Table 5

Embodiment 30-34

Except for the following differences, all the other are identical with embodiment 1, and the catalyst repetitive cycling uses the influence to reaction to the results are shown in Table 6.

Table 6

Claims

1, a kind of solid base catalyst is characterized in that: this catalyst is after organic metal salt and carrier are at room temperature carried out ground and mixed, high-temperature roasting and getting; The concrete practice is: organic metal salt and carrier are placed mortar, and organic metal salt is 1～12: 10 with the ratio of carrier quality, grinds 1～2h under room temperature, 300～1000 ℃ of following roasting 5～10h in the Muffle furnace then, promptly; Described organic metal salt is alkali metal formate, acetate, oxalates or citrate; Described carrier is aluminium oxide, calcium oxide, magnesia, zinc oxide, zirconia, active carbon, molecular sieve, diatomite, carclazyte, silica gel or boehmite.

2, the application of the described solid base catalyst of a kind of claim 1 in the preparation biodiesel, it is characterized in that biodiesel adopts the ester-interchange method preparation, concrete steps are: having electromagnetic agitation, thermometer adds grease, low-carbon alcohols, solid base catalyst and adds hot reflux and stir 1～3h in the three neck containers of reflux condensing tube; Heating and temperature control is at 50～110 ℃; With reacted material filtering, leach catalyst and filtrate, filtrate is carried out separatory, tells lower floor's glycerine, and the adding mass fraction is 5～10% NaHCO in the mixture of upper strata ₃Solution, its addition are 2～6 times of upper strata mixture quality, and washing is told upper organic phase with separatory funnel again to neutral, with organic facies with anhydrous MgSO ₄Drying removes by filter drier, and decompression distillation obtains nearly light yellow opaque products and is biodiesel; The mass ratio of described adding grease, low-carbon alcohols, solid base catalyst is 1: 0.1～0.5: 0.04～0.1; Described grease is waste oil, the waste oil in vegetable fat, animal tallow or the production process; Described low-carbon alcohols is methyl alcohol, ethanol, propyl alcohol or butanols.