CN1394680A - Nano-grade lanthanum titanium compound oxide, its preparation method and application - Google Patents
Nano-grade lanthanum titanium compound oxide, its preparation method and application Download PDFInfo
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- CN1394680A CN1394680A CN 02113313 CN02113313A CN1394680A CN 1394680 A CN1394680 A CN 1394680A CN 02113313 CN02113313 CN 02113313 CN 02113313 A CN02113313 A CN 02113313A CN 1394680 A CN1394680 A CN 1394680A
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Abstract
The composition of nano-grade lanthanum titanium compound oxide is La2-4Ti2-9O7-24, in which La:Ti:O (atom ratio)=2-4:2-9:7-24, LawTi2O7 and La4Ti9O24 are existed in micro-crystal state, its average grain size is 28nm-35nm, and its specific surface area is greater than 60 sq.m/g. Said compound oxide can be used as catalyst for preparing lactide by utilizing lactic acid dehydration and polycondensation, can improve viscosity of reaction system and can effectively reduce lactic acid oligomer cracking temp., and the yield of lactide is 80%-90%.
Description
Technical field
The present invention relates to a kind of nano level lanthanum titanium composite oxide super fine and synthesis technique and purposes.
Technical background
The binary lanthanum titanium oxide generally adopts the flux method preparation [to see Mitsunori Yokoyama, Journalof Crystal Growth, North-Holland Amsterdanm, 1986 V96, P490～496 and Macchesney J B, J.Am.Ceram.Soc., 1962,45 (9): P416～422] monocrystalline series, solid phase method [Michael Kestigian, Roland Ward, J.Am.Soc., 1995,77 (12): P6199～6200 and Xiang Yong etc., silicate circular, 2001, V2, P51～54] preparation La
2O
3-TiO
2Its purposes of series mainly is as ceramic medium material.The crystalline flour of the synthetic perovskite-type compounds of hydro-thermal method [Matijevic, et al.United Staes Patent 5900223, May4,1999].The lanthanum titanium has unique electronic structure (La4f
05d
16s
2, Ti3d
24s
2) in more unoccupied orbital is arranged, the good electron transfer orbit can be provided, therefore have very high catalytic activity.The lanthanum titanium composite oxide that synthesizes with the two kinds of preparation methods that go forward reduces the stray crystal phase by improving calcining heat, and this often easily causes oxide diameter sizes big (micron order), the less (＜10m of specific area
2/ g); And the particle size range of the lanthanum titanium composite oxide that the third method is synthesized is very big, synthetic method is not convenient, it is low to be applied in the organic material building-up process general dispersive property, phenomenons such as reunion easily take place, and do not reach the embedding phenomenon of slowing down the activated centre and reduce the charing phenomenon that reaction system takes place because of excessive thickness under hot conditions.
Nano-grade lanthanum titanium compound oxide of the present invention, be than the calcining heat of bibliographical information [1400～1675 ℃, Macchesney J B, Sauer H A.J.Am.Ceram.Soc., 1962,45 (9): 416～422; 1300～1360 ℃ of Xiang Yong etc., silicate circular, 2001, V2 P51～54] under the lower temperature conditions, with sol-gel process synthetic with La
2Ti
2O
7And La
4Ti
9O
24Be principal crystalline phase, do not have or almost do not have free La
2O
3Composite oxides with the dephasign appearance.
The object of the present invention is to provide a kind of nano-grade lanthanum titanium compound oxide, and the easy method for making under the normal condition, a further object of the present invention provides its purposes as catalyst.
Summary of the invention
Technical scheme of the present invention is:
A kind of nano-grade lanthanum titanium compound oxide, its feature consists of La
2～4Ti
2～9O
7～24, La: Ti: O (atomic ratio)=2～4 wherein: 2～9: 7～24, La
2Ti
2O
7And La
4Ti
9O
24Exist with microcrystalline state, average grain diameter is 28nm～35nm, and specific area is greater than 60m
2/ g.
The method for making of lanthanum titanium composite oxide of the present invention is as follows:
Lanthanum sesquioxide is dissolved in nitric acid, adds small amount of deionized water, form the water white transparency lanthanum nitrate hexahydrate, the molar concentration of lanthanum nitrate is 0.5～0.8mol/dm
3Room temperature adds an amount of polyethylene glycol in the lanthanum nitrate hexahydrate of continuous stirring, it is dissolved fully, gets water white transparency colloidal sol (S1), and wherein the molecular weight of polyethylene glycol is 1000～20000.Butyl titanate is disperseed with absolute ethyl alcohol, add an amount of polyethylene glycol, regulate between pH to 1～2 with red fuming nitric acid (RFNA), stirring at normal temperature forms light yellow vitreosol (S2), butyl titanate: absolute ethyl alcohol=1: 20-30, the molecular weight of polyethylene glycol are 1000～20000.Colloidal sol S1 slowly is added drop-wise among the colloidal sol S2 of vigorous stirring, 90 ℃ of following vigorous stirring decompression dehydrations 3～6 hours, milky colloidal sol S3, naturally cool to room temperature and get milky gel G.30 ℃～40 ℃ water-bath ageings 24 hours, 100 ℃～120 ℃ dryings 10 hours 750 ℃～900 ℃ calcinings 3～5 hours, were pulverized one to four time through air-flow then with gel, average grain diameter less than 35nm, specific area is greater than 60m
2The nano-grade lanthanum titanium compound oxide of/g.
Nano-grade lanthanum titanium compound oxide of the present invention can be as the catalyst of acid by dehydrating lactic polycondensation and cracking synthesis of lactide.120 ℃～130 ℃ of reaction temperatures, pressure 0.25Kpa, catalyst causes the acid by dehydrating lactic polycondensation and becomes low molecular weight, 180 ℃～240 ℃ of temperature, pressure 0.1Kpa, lactide conversions is 80%～90%, the temperature of lactic acid oligomer cracking synthesis of lactide reduces by 20 ℃～30 ℃ than the reaction system PLA cracking temperature of conventional catalyst effect, catalyst has the reaction system of reduction viscosity simultaneously, effectively prevents the effect of the charing of lactic acid oligomer.
The specific embodiment
Embodiment 1 is 2: 1 preparation organic matter presomas with raw material by lanthanum titanium metal ions mol ratio.Butyl titanate is disperseed with absolute ethyl alcohol, wherein the Titanium ion: the absolute ethyl alcohol mol ratio is 1: 20, and regulating the pH value with red fuming nitric acid (RFNA) is 1.0, gets titanium colloidal sol.Lanthanum sesquioxide is dissolved in nitric acid, adds deionized water, lanthanum sesquioxide: nitric acid: the deionized water mol ratio is 1: 2: 16, and the molar concentration of lanthanum nitrate is 0.5mol/dm
3, an amount of polyethylene glycol (molecular weight is 1000) is dissolved in lanthanum nitrate hexahydrate, 40 ℃ of stirrings generate colourless colloidal sol.Lanthanum colloidal sol is slowly splashed into the titanium colloidal sol of vigorous stirring (rotating speed is 3000 rev/mins), 90 ℃ were stirred decompression dehydration 3 hours down fast, generate milky colloidal sol, naturally cool to room temperature and generate the milky gel, with gel 40 ℃ of water-bath ageings 24 hours, 100 ℃ of dryings 10 hours, then 850 ℃ of calcinings 3 hours, get extremely puffy solid of brilliant white, pulverize once, obtain containing La through gas
2Ti
2O
7Monoclinic system and La
4Ti
9O
24Two kinds of components of rhombic system, average grain diameter 35nm, specific area 60m
2The nano-grade lanthanum titanium compound oxide of/g.
Embodiment 2 is 2: 1 preparation organic matter presomas with raw material by lanthanum titanium metal ions mol ratio.Butyl titanate is disperseed with absolute ethyl alcohol, wherein the Titanium ion: the absolute ethyl alcohol mol ratio is 1: 26, and regulating the pH value with red fuming nitric acid (RFNA) is 1.5, gets titanium colloidal sol.Lanthanum sesquioxide is dissolved in nitric acid, adds deionized water, lanthanum sesquioxide: nitric acid: the deionized water mol ratio is 1: 2: 15, and the molar concentration of lanthanum nitrate is 0.6mol/dm
3, an amount of polyethylene glycol (molecular weight is 4000) is dissolved in lanthanum nitrate hexahydrate, 30 ℃ of stirrings generate colourless colloidal sol.Lanthanum colloidal sol is slowly splashed into the titanium colloidal sol of vigorous stirring (rotating speed is 3500 rev/mins), 90 ℃ were stirred decompression dehydration 4 hours down fast, generate milky colloidal sol, naturally cool to room temperature and generate the milky gel, with gel 40 ℃ of water-bath ageings 24 hours, 110 ℃ of dryings 10 hours, then 800 ℃ of calcinings 3 hours, get extremely puffy solid of brilliant white, pulverize once, obtain containing La through gas
2Ti
2O
7Monoclinic system and La
4Ti
9O
24Two kinds of components of rhombic system, average grain diameter 31nm, specific area 63m
2The nano-grade lanthanum titanium compound oxide of/g.
Embodiment 3 is 2: 1 preparation organic matter presomas with raw material by lanthanum titanium metal ions mol ratio.Butyl titanate is disperseed with absolute ethyl alcohol, wherein the Titanium ion: the absolute ethyl alcohol mol ratio is 1: 30, and regulating the pH value with red fuming nitric acid (RFNA) is 2.0, gets titanium colloidal sol.Lanthanum sesquioxide is dissolved in nitric acid, adds deionized water, lanthanum sesquioxide: nitric acid: the deionized water mol ratio is 1: 2: 14, and the molar concentration of lanthanum nitrate is 0.8mol/dm
3, an amount of polyethylene glycol (molecular weight is 20000) is dissolved in lanthanum nitrate hexahydrate, 30 ℃ of stirrings generate colourless colloidal sol.Lanthanum colloidal sol is slowly splashed into the titanium colloidal sol of vigorous stirring (rotating speed is 4000 rev/mins), 90 ℃ were stirred decompression dehydration 6 hours down fast, generate milky colloidal sol, naturally cool to room temperature and generate the milky gel, with gel 40 ℃ of water-bath ageings 24 hours, 120 ℃ of dryings 10 hours, then 750 ℃ of calcinings 3 hours, get extremely puffy solid of brilliant white, pulverize once, obtain containing La through gas
2Ti
2O
7Monoclinic system and La
4Ti
9O
24Two kinds of components of rhombic system, average grain diameter 28nm, specific area 66m
2The nano-grade lanthanum titanium compound oxide of/g.
Embodiment 4 nano-grade lanthanum titanium compound oxide of the present invention (average diameter=35nm, specific area=60m
2/ g) as being cracked into the lactide catalyst for reaction after the acid by dehydrating lactic polycondensation.Reaction condition: D, L-lactic acid, 60 ℃, 0.25KPa took off Free water 2 hours; Add catalyst, (molecule) water polycondensation reaction 3 hours is taken off in 120 ℃ of decompressions, generates water 12ml, wherein lactic acid: catalyst quality is than=100: 1; Change receiving system, 170 ℃～230 ℃, under high vacuum (0.1KPa) condition, low molecular weight is cracked into lactide, and steams through decompression, and afterreaction finished in 3.5 hours, and the carbonization residue amount in the reactor is 6% of a lactic acid, and the lactide productive rate is 80%.
Embodiment 5 nano-grade lanthanum titanium compound oxide of the present invention (average diameter=33nm, specific area=62m
2/ g) as being cracked into the lactide catalyst for reaction after the acid by dehydrating lactic polycondensation.Reaction condition: D, L-lactic acid, 60 ℃, 0.25KPa took off Free water 2 hours; Add catalyst, (molecule) water polycondensation reaction 3.5 hours is taken off in 120 ℃ of decompressions, generates water 14ml, wherein lactic acid: catalyst quality is than=150: 1; Change receiving system, 170 ℃～230 ℃, under high vacuum (0.1KPa) condition, low molecular weight is cracked into lactide, and steams through decompression, and afterreaction finished in 3.5 hours, and the carbonization residue amount in the reactor is 5% of a lactic acid, and the lactide productive rate is 83%.
Embodiment 6 nano-grade lanthanum titanium compound oxide of the present invention (average diameter=28nm, specific area=66m
2/ g) as being cracked into the lactide catalyst for reaction after the acid by dehydrating lactic polycondensation.Reaction condition: D, L-lactic acid, 60 ℃, 0.25KPa took off Free water 2 hours; Add catalyst, (molecule) water polycondensation reaction 3.5 hours is taken off in 120 ℃ of decompressions, generates water 13ml, wherein lactic acid: catalyst quality is than=200: 1; Change receiving system, 170 ℃～230 ℃, under high vacuum (0.1KPa) condition, low molecular weight is cracked into lactide, and steams through decompression, and afterreaction finished in 3.5 hours, and the carbonization residue amount in the reactor is 3% of a lactic acid, and the lactide productive rate is 90%.
Description of drawings
Fig. 1 is a lanthanum titanium composite oxide XRD figure spectrum;
Fig. 2 is a lanthanum titanium composite oxide laser detection afm scan collection of illustrative plates.
Claims (3)
1. nano-grade lanthanum titanium compound oxide, its feature consists of La
2～4Ti
2～9O
7～24, La: Ti: O (atomic ratio)=2～4 wherein: 2～9: 7～24, La
2Ti
2O
7And La
4Ti
9O
24Exist with microcrystalline state, average grain diameter is 28nm～35nm, and specific area is greater than 60m
2/ g.
2. the preparation method of the described nano-grade lanthanum titanium compound oxide of claim 1 is characterized in that:
(1) lanthanum sesquioxide is dissolved in nitric acid, adds small amount of deionized water, form the water white transparency lanthanum nitrate hexahydrate, the molar concentration of lanthanum nitrate is 0.5～0.8mol/dm
3
(2) add an amount of polyethylene glycol in the lanthanum nitrate hexahydrate that room temperature constantly stirs, it is dissolved fully, get water white transparency colloidal sol (S1), wherein the molecular weight of polyethylene glycol is 1000～20000.
(3) butyl titanate is disperseed with absolute ethyl alcohol, add an amount of polyethylene glycol, regulate between pH to 1～2, form light yellow vitreosol (S2) under the stirring at normal temperature with red fuming nitric acid (RFNA), butyl titanate: the mol ratio of absolute ethyl alcohol=1: 20～30, the molecular weight of polyethylene glycol are 1000～20000.
(4) colloidal sol S1 slowly is added drop-wise among the colloidal sol S2 of vigorous stirring, 90 ℃ of following vigorous stirring decompression dehydrations 3～6 hours, milky colloidal sol S3, naturally cool to room temperature and get milky gel G.
(5) with gel 30 ℃～40 ℃ water-bath ageings 24 hours, 100 ℃～120 ℃ dryings 10 hours 750 ℃～900 ℃ calcinings 3～5 hours, are pulverized one to four time through air-flow then, average grain diameter 28nm～35nm, specific area is greater than 60m
2The nano-grade lanthanum titanium compound oxide of/g.
3. the purposes of the described nano-grade lanthanum titanium compound oxide of claim 1 is characterized in that as acid by dehydrating lactic polycondensation synthesis of lactide catalyst for reaction.
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101195678B (en) * | 2006-12-08 | 2011-05-18 | 东丽纤维研究所（中国）有限公司 | Catalyst for production of polylactic acid by direct polycondensation method |
| CN102432183A (en) * | 2011-09-08 | 2012-05-02 | 中国科学院过程工程研究所 | Nanomicro-grade titanium oxide glass spheres and preparation method thereof |
| CN101659628B (en) * | 2009-09-09 | 2012-09-12 | 重庆大学 | Titanium complex, preparation method and use thereof |
| CN105645469A (en) * | 2016-03-09 | 2016-06-08 | 武汉科技大学 | Nano rodlike lanthanum titanate powder and preparation method thereof |
| CN105944710A (en) * | 2016-05-20 | 2016-09-21 | 沈阳理工大学 | Quartz sand supported lanthanum titanate photocatalyst and method for preparing same |
| CN108314079A (en) * | 2018-04-10 | 2018-07-24 | 四川大学 | A kind of regulation and control lanthanium titanate La2Ti2O7（LTO）The method of powder size |
| CN108660442A (en) * | 2018-04-25 | 2018-10-16 | 东南大学 | LaxTiyOzOxide includes the LaxTiyOzThe composite material and preparation method of oxide |
| CN110921702A (en) * | 2019-12-02 | 2020-03-27 | 吉林师范大学 | Preparation method of small-size lanthanum titanate nanoparticles |
| CN110937625A (en) * | 2019-12-02 | 2020-03-31 | 吉林师范大学 | Preparation method of lanthanum titanate nanoparticles with defects |
| CN113845508A (en) * | 2021-10-28 | 2021-12-28 | 南京大学 | Method for preparing lactide by using bimetallic composite catalyst |
| CN117105657A (en) * | 2023-09-18 | 2023-11-24 | 深圳市华辰新材料科技有限公司 | Low-temperature sintering preparation method and equipment of nanoscale lanthanum titanate |
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2002
- 2002-02-01 CN CN 02113313 patent/CN1239255C/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101195678B (en) * | 2006-12-08 | 2011-05-18 | 东丽纤维研究所（中国）有限公司 | Catalyst for production of polylactic acid by direct polycondensation method |
| CN101659628B (en) * | 2009-09-09 | 2012-09-12 | 重庆大学 | Titanium complex, preparation method and use thereof |
| CN102432183A (en) * | 2011-09-08 | 2012-05-02 | 中国科学院过程工程研究所 | Nanomicro-grade titanium oxide glass spheres and preparation method thereof |
| CN102432183B (en) * | 2011-09-08 | 2014-02-26 | 中国科学院过程工程研究所 | Nanomicro-grade titanium oxide glass spheres and preparation method thereof |
| CN105645469A (en) * | 2016-03-09 | 2016-06-08 | 武汉科技大学 | Nano rodlike lanthanum titanate powder and preparation method thereof |
| CN105944710A (en) * | 2016-05-20 | 2016-09-21 | 沈阳理工大学 | Quartz sand supported lanthanum titanate photocatalyst and method for preparing same |
| CN108314079A (en) * | 2018-04-10 | 2018-07-24 | 四川大学 | A kind of regulation and control lanthanium titanate La2Ti2O7（LTO）The method of powder size |
| CN108660442A (en) * | 2018-04-25 | 2018-10-16 | 东南大学 | LaxTiyOzOxide includes the LaxTiyOzThe composite material and preparation method of oxide |
| CN108660442B (en) * | 2018-04-25 | 2020-10-02 | 东南大学 | LaxTiyOzOxide comprising the LaxTiyOzComposite material of oxide and preparation method thereof |
| CN110921702A (en) * | 2019-12-02 | 2020-03-27 | 吉林师范大学 | Preparation method of small-size lanthanum titanate nanoparticles |
| CN110937625A (en) * | 2019-12-02 | 2020-03-31 | 吉林师范大学 | Preparation method of lanthanum titanate nanoparticles with defects |
| CN113845508A (en) * | 2021-10-28 | 2021-12-28 | 南京大学 | Method for preparing lactide by using bimetallic composite catalyst |
| CN113845508B (en) * | 2021-10-28 | 2022-03-29 | 南京大学 | Method for preparing lactide by using bimetallic composite catalyst |
| CN117105657A (en) * | 2023-09-18 | 2023-11-24 | 深圳市华辰新材料科技有限公司 | Low-temperature sintering preparation method and equipment of nanoscale lanthanum titanate |
| CN117105657B (en) * | 2023-09-18 | 2024-05-07 | 深圳市华辰新材料科技有限公司 | Low-temperature sintering preparation method and equipment of nanoscale lanthanum titanate |
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