CN101590400B - Method for preparing nano magnetic solid base catalyst used for transesterification reaction - Google Patents

Abstract

The invention provides a method for preparing a nano magnetic solid base catalyst used for transesterification reaction. The method comprises the following steps: 1) preparing water solution from FeSO4.7H2O and Fe2(SO4)3.7H2O according to a molar ratio of 1:2, controlling the total concentration of iron ions to 0.3 mol/L, adding ammonia water into the water solution drop by drop by stirring at the temperature of between 60 and 65 DEG C, drastically stirring the water solution to obtain oil black sediment, aging the water solution for 1 hour, removing the excessive ammonia water in a water bath, repeatedly washing the sediment till the water solution is neutral, detecting the water solution and determining that no SO4<-2> exists; 2) preparing mixed water solution of CaCl2 and a product of the step 1) according to a molar ratio of Ca<2+> to Fe ions of 7:1, adding secondary distilled water into the solution, drastically stirring the solution, adding NaOH solution into the solution drop by drop, raising the temperature of the solution to 65 DEG C after the dropping is finished, continuously stirring the solution and aging the solution for 18 hours, attracting magnetic substances by using a neodymium-iron-boron permanent magnet, repeatedly washing a product till the solution is neutral, and drying the product by vacuum; and 3) calcinating the product at 800 DEG C, and converting the product into a composite oxide, namely the nano magnetic solid base catalyst. The method has the advantages of high efficiency for reclaiming the catalyst, simple process, high catalytic activity and efficiency, and reduction of the cost.

Description

A kind of preparation method who is used for the nano magnetic solid base catalyst of transesterification

Technical field

The present invention relates to technical field of chemistry and chemical engineering, relate in particular to a kind of preparation method who is used for the nano magnetic solid base catalyst of transesterification.

Technical background

Current society, the mankind more and more rely on the energy, and still, the human traditional energy that relies on over the past thousands of years is fewer and feweri, and many large-scale collieries, oil field are close to exhaustion through the exhaustive exploitation in a century in the world wide.So we must find a kind of novel energy that can replace traditional energy.And the drawback of traditional energy also highlights day by day.The influence of the air pollution maximum that to be traditional energy cause the human lives, the annual death that is caused by air pollution is being risen year by year, and the malignant pollution accident takes place frequently.The intensity of acid rain and scope are risen year by year and enlarge along with the burning of traditional energy enters airborne various oxysulfide and nitrogen oxide, cause acidification, forest and the death of crops large tracts of land.Next is that too much carbon dioxide is discharged into and causes greenhouse effects in the atmosphere, and has caused thus such as glacier, the two poles of the earth and melt, and raise on the sea level, phenomenons such as unusual weather conditions, and natural calamity grows in intensity.Therefore, it is very urgent to seek a kind of novel energy of environmental protection.The 3rd, since the industrial revolution, human utilization, especially oil round traditional energy with and the application of spin-off gasoline, diesel oil, developed a large amount of equipment.So, find a kind of various physicochemical property alternative energy source similar to remove to develop new equipment for society saves a large amount of costs to it.

Biodiesel has entered people's the visual field under this background.Biodiesel also has many good qualities: because biodiesel flash-point height does not belong to dangerous material, the security advantages aspect transportation, storage, use is obvious; Lubricity is good, can reduce the wear rate of injection pump, engine cylinder-body and connecting rod, prolongs parts service life; Calorific value is higher than traditional petrifaction diesel; China is developing large agricultural country, and is populous, and resource-constrained, especially energy resources, energy supply problem have become one of key factor of restriction Chinese society and sustainable economic development.So, economize on resources, reduce cost, clean, efficiently under the prerequisite, the development biodiesel will have more importantly meaning

Transesterification in traditional production of biodiesel technology adopts homogenous alkali catalyst and since the strong basicity of catalyst with can make it have very high catalytic activity with the characteristic that reactant fully contacts.But its follow-up complex treatment process, environmental pollution is bigger.Characteristics such as it is easily separated to come the catalysis transesterification to have with solid base catalyst, and subsequent technique is simple, but because the surface area of solid base catalyst is less, contact with reactant abundant inadequately, the reduction rate of catalysis reaction.The nano-scale magnetic solid base catalyst is because of its huge specific area, make its characteristics with homogeneous catalyst, can fully contact with reactant, having magnetic again can reclaim catalyst by externally-applied magnetic field, thereby simplified subsequent treatment process, also can not impact environment.

Summary of the invention

The purpose of this invention is to provide a kind of preparation method who is used for the nano magnetic solid base catalyst of transesterification, both catalysis transesterification efficiently can utilize the rapid separation of externally-applied magnetic field realization response thing again.

For reaching above-mentioned purpose, preparation method of the present invention has taked following steps:

1) preparation of carrier

With FeSO ₄7H ₂O and Fe ₂(SO ₄) ₃7H ₂1: 2 in molar ratio ratio of O adds dissolved in distilled water and is mixed with the aqueous solution, and control iron ion total concentration is 0.3mol/L.This solution is joined in the reaction vessel, dropwise adding ammoniacal liquor under the 60-65 ℃ of temperature and under stirring, vigorous stirring obtains the precipitation of glossy black look, and behind the ageing 1h, excess of ammonia water is removed in water-bath, and cyclic washing is precipitated to neutrality, gets supernatant and determines no SO through checking ₄ ^2-Black precipitate is standby;

Carrier through method for preparing is analyzed through X-ray diffractometer (X) RD, and according to Scherrer formula (1), can estimate that its particle diameter average-size has reached nanoscale.

$D=\frac{0.89\mathrm{\&lambda;}}{\mathrm{\&beta;}\cos \mathrm{\&theta;}}---\left(1\right)$

In the formula λ be X ray wavelength (/nm), β is pure diffraction maximum halfwidth, θ is a semi diffraction angle.

2) load of active component

Preparation CaCl ₂With the mixed aqueous solution of the black precipitate of step 1) preparation, wherein Ca ²⁺With Fe ion (Fe ²⁺+ Fe ³⁺) molar ratio be 7: 1.Add redistilled water, vigorous stirring.The NaOH solution that dropwise adds 1mol/l, precipitating the continuation generation to solution, be warming up to 60-65 ℃ after dropwising and continue to stir ageing 18h, is 2200 Gausses' rubidium iron boron permanent magnet absorption magnetisable material with magnetic force, cyclic washing causes neutrality, and product is in 80 ℃ of vacuum drying 12h;

3) activation of active component

At last with step 2) product that obtains is 800 ℃ of calcination, is transformed into composite oxides, is nano magnetic solid base catalyst.

Than traditional solid base catalyst, as calcium oxide, magnesia etc., the advantage of catalyst of the present invention is: reclaim the catalyst efficiency height, technology is simple, reduces cost, and catalytic activity is big, the efficient height.

The specific embodiment

Below in conjunction with embodiment the present invention is done further statement.

Embodiment 1

Step 1:FeSO ₄7H ₂O and Fe ₂(SO ₄) ₃7H ₂O is mixed with the aqueous solution in 1: 2 ratio adding dissolved in distilled water, and control iron ion total concentration is 0.3mol/L.This solution is joined in the beaker, under 65 ℃ of temperature and 450r/min dropwise to add mass concentration under stirring be 25% ammoniacal liquor, vigorous stirring obtains the precipitation of glossy black look, behind the ageing 1h, water-bath progressively is warming up to 85 ℃, and 1h is to evaporate excess of ammonia water, cyclic washing is precipitated to neutrality, get supernatant and add barium chloride solution, precipitation does not generate, and determines no SO ₄ ^2-Black precipitate is standby.

Step 2: get CaCl ₂Be made into the aqueous solution, get the black precipitate that step 1) makes again and join CaCl ₂In the solution, keep Ca ²⁺With Fe ion (Fe ²⁺+ Fe ³⁺) molar ratio be 7: 1.Add redistilled water, vigorous stirring is got NaOH and is mixed with lmol/l solution, and it is dropwise joined in the above-mentioned beaker, precipitates the continuation generation to solution.Being warming up to 65 ℃ after dropwising and continue stirring ageing 18h, is that 2200 Gausses' rubidium iron boron permanent magnet is drawn magnetisable material with magnetic force, and cyclic washing is to neutrality, and product is in 80 ℃ of vacuum drying 12h,

Step 3: at last with step 2) 800 ℃ of calcination of the product that obtains are transformed into composite oxides, are nano magnetic solid base catalyst.

Adopt the transesterification of Jatropha curcas oil that the catalytic activity of nano magnetic solid base catalyst is estimated.The Jatropha curcas oil of 120ml and the methyl alcohol of 73.5ml are poured in the there-necked flask, and the catalyst of adding 2wt%, reaction is 4 hours under 70 ℃ reaction temperature, reaction back standing demix, get supernatant liquid Tianjin, island GC2010 gas Chromatographic Determination biodiesel content, and under the effect of externally-applied magnetic field, reclaim catalyst.Evaluation result is as shown in table 1:

Table 1 embodiment evaluating catalyst result

Reaction temperature	70℃
		Reaction time	4h
Catalyst amount	2wt％
		Molar ratio of methanol to oil	15∶1
Biodiesel production rate	98％
		Reclaim catalyst	91.45％

Claims (2)

1. preparation method who is used for the nano magnetic solid base catalyst of transesterification is characterized in that being made up of following steps:

1) preparation of carrier

With FeSO ₄7H ₂O and Fe ₂(SO ₄) ₃7H ₂1: 2 in molar ratio ratio of O adds dissolved in distilled water and is mixed with the aqueous solution, control iron ion and ferrous ion total concentration are 0.3mol/L, this solution is joined in the reaction vessel, dropwise adding ammoniacal liquor under stirring under the 60-65 ℃ of temperature, vigorous stirring obtains the precipitation of glossy black look, behind the ageing 1h, excess of ammonia water is removed in water-bath, and cyclic washing is precipitated to neutrality, gets supernatant and determines no SO through checking ₄ ^2-Black precipitate is standby;

2) load of active component

Preparation CaCl ₂With the mixed aqueous solution of the black precipitate of step 1) preparation, wherein Ca ²⁺With the molar ratio of iron ion and ferrous ion summation be 7: 1, add redistilled water, vigorous stirring, the NaOH solution that dropwise adds 1mol/l, precipitating the continuation generation to solution, be warming up to 65 ℃ and continue to stir ageing 18h, is 2200 Gausses' rubidium iron boron permanent magnet absorption magnetisable material with magnetic force, cyclic washing is to neutral, and product is in 80 ℃ of vacuum drying 12h;

3) activation of active component

At last with step 2) product that obtains is 800 ℃ of calcination, is transformed into composite oxides, is nano magnetic solid base catalyst.

2. the preparation method who is used for the nano magnetic solid base catalyst of transesterification according to claim 1 is characterized in that the ammoniacal liquor in the described step 1) is that mass concentration is 25% ammoniacal liquor.