CN101249432A

CN101249432A - Novel solid body base catalyst and applications thereof in biological diesel oil synthesizing

Info

Publication number: CN101249432A
Application number: CNA2008100352861A
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 application thereof on the preparation of biodiesel. The catalyst is prepared by the solid-phase reaction between metal nitrate and base or alkali carbonate and calcining at a high temperature. The biodiesel is prepared by transesterification including adding oil and fat, low carbon alcohol and the solid base catalyst into a three-neck container; refluxing under heating and stirring; filtering to remove the catalyst; demixing the filtrate; separating glycerol at the lower layer, adding NaHCO3 solution to mixture at the upper layer; drying with anhydrous MgSO4; reducing the pressure and distilling. The application of the catalyst on the preparation of the biodiesel has the advantages of high yield, cheap catalyst, small catalyst consumption, mild reaction conditions, short reaction time, reutilization of the catalyst, environment friendliness and low requirement for the raw material.

Description

A kind of 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 is after metal nitrate and alkali or alkali carbonate are at room temperature ground solid phase reaction, high-temperature roasting and getting; The concrete practice is: metal nitrate and alkali or alkali carbonate are placed mortar, metal nitrate is 1～12: 10 with the ratio of the quality of alkali or alkali carbonate, under room temperature, grind 1～2h, 300～1000 ℃ of following roasting 5～10h in the Muffle furnace then, promptly; Described metal nitrate is magnesium nitrate, aluminum nitrate, zinc nitrate, calcium nitrate or strontium nitrate; Described alkali or alkali carbonate are NaOH, potassium hydroxide, sodium carbonate or potash.

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 90%.

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

Compare with background technology, advantage of the present invention is: catalyst has active component and is evenly distributed, raw material availability height, simple synthetic method; Catalyst is used for the synthetic advantage of biodiesel: (1) productive rate height; (2) catalyst is cheap, and catalyst amount is little, accounts for 0.5～3% of reaction raw materials gross weight; (3) reaction condition gentleness, the reaction time is short; (4) catalyst is reusable; (5) there is not environmental pollution; (6) low 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 magnesium nitrate and 10g potassium hydroxide are placed mortar, under room temperature, grind about 1h, 800 ℃ of following roasting 5h in the Muffle furnace then, promptly.

The 2nd step ester exchange reaction

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

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

With the 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 mixture 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, magnesium nitrate is pressed the consumption of table 1.

Table 1

Embodiment 7-11

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

Table 2

Embodiment 12-15

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

Table 3

Embodiment 16-20

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 21-25

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 26-30

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: after metal nitrate and alkali or alkali carbonate are at room temperature ground solid phase reaction, and high-temperature roasting and getting; The concrete practice is: metal nitrate and alkali or alkali carbonate are placed mortar, metal nitrate is 1～12: 10 with the ratio of the quality of alkali or alkali carbonate, under room temperature, grind 1～2h, 300～1000 ℃ of following roasting 5～10h in the Muffle furnace then, promptly; Described metal nitrate is magnesium nitrate, aluminum nitrate, zinc nitrate, calcium nitrate or strontium nitrate; Described alkali or alkali carbonate are NaOH, potassium hydroxide, sodium carbonate or potash.

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: 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.