JPH0339972B2 - - Google Patents
Info
- Publication number
- JPH0339972B2 JPH0339972B2 JP1478382A JP1478382A JPH0339972B2 JP H0339972 B2 JPH0339972 B2 JP H0339972B2 JP 1478382 A JP1478382 A JP 1478382A JP 1478382 A JP1478382 A JP 1478382A JP H0339972 B2 JPH0339972 B2 JP H0339972B2
- Authority
- JP
- Japan
- Prior art keywords
- tma
- zeolite
- crystallization
- offretite
- reaction mixture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000010457 zeolite Substances 0.000 claims description 34
- 238000002425 crystallisation Methods 0.000 claims description 27
- 230000008025 crystallization Effects 0.000 claims description 27
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 25
- 229910021536 Zeolite Inorganic materials 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 20
- 238000003756 stirring Methods 0.000 claims description 20
- 239000011541 reaction mixture Substances 0.000 claims description 19
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 15
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 7
- 230000002194 synthesizing effect Effects 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 238000001308 synthesis method Methods 0.000 claims description 3
- QEMXHQIAXOOASZ-UHFFFAOYSA-N tetramethylammonium Chemical compound C[N+](C)(C)C QEMXHQIAXOOASZ-UHFFFAOYSA-N 0.000 claims description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 17
- 239000013078 crystal Substances 0.000 description 17
- 239000011148 porous material Substances 0.000 description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000012535 impurity Substances 0.000 description 9
- 150000002500 ions Chemical class 0.000 description 9
- 239000000377 silicon dioxide Substances 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 239000003054 catalyst Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 239000011734 sodium Substances 0.000 description 5
- 150000001768 cations Chemical class 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000002808 molecular sieve Substances 0.000 description 4
- 238000000634 powder X-ray diffraction Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 3
- 229910052906 cristobalite Inorganic materials 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- 229910001388 sodium aluminate Inorganic materials 0.000 description 3
- 229910052682 stishovite Inorganic materials 0.000 description 3
- 229910052905 tridymite Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000005070 ripening Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052665 sodalite Inorganic materials 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- 229910004283 SiO 4 Inorganic materials 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- -1 alkaline earth metal cations Chemical class 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000005341 cation exchange Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000012024 dehydrating agents Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 229910052675 erionite Inorganic materials 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052680 mordenite Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910009112 xH2O Inorganic materials 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Landscapes
- Silicates, Zeolites, And Molecular Sieves (AREA)
Description
本発明はゼオライトの改良合成法に関し、特に
ゼオライトの一種である微細で、かつ高純度のオ
フレタイト結晶を短時間で合成する方法を提供す
るものである。
ゼオライトはギリシヤ語の沸騰する石という意
味で、沸石水を含む結晶性アルミノシリケートで
ある。その基本構造は、珪素を中心として形成さ
れる4つの酸素が頂点に配置したSiO4四面体と、
この珪素の代わりにアルミニウムが置換した
AlO4四面体とが、O/(Al+Si)の原子比が2
となるように酸素を共有しながら規則正しく三次
元的に配列している。AlO4四面体の負電荷はア
ルカリ金属やアルカリ土類金属の陽イオンを含む
ことによつてバランスされている。又、四面体の
配列の仕方で種々の大きさの細孔が形成され、細
孔に、通常水分子や交換可能な陽イオンが存在し
ている。ゼオライトを脱水処理したり、ゼオライ
ト中の陽イオンを適当な他の陽イオンに交換した
ものは、特定の分子を細孔に捕捉する機能を持つ
いわゆる分子篩として、あるいは細孔内のみで反
応させ得る触媒として、又はイオン交換体、さら
に触媒の担体として等々いろいろな分野で利用さ
れている工業的価値ある物質である。
ゼオライトには、種々の結晶構造を持つものが
知られており、それらは粉末X線回折図で区別が
できる。ゼオライトは天然にも存在し、現在では
天然に存在するゼオライトを合成によつても得る
ことができる。又、天然に存在しないゼオライト
でも合成されるようになつた。
ゼオライトの一種であるオフレタイト
(OFFRETITE)は天然にも存在し、このものは
六方晶系(格子定数a;13.3A、c;7.59A)の
結晶構造を持ち、シクロヘキサンを吸着できる細
孔を有する。又、オフレタイトはその合成反応系
にテトラメチルアンモニウムイオン(以後TMA
イオンという)を存在させて合成できることか
ら、得られたオフレタイトは“TMAオフレタイ
ト”とも呼ばれている。このものの化学組成は、
M2O・Al2O3・(5〜10)SiO2・xH2Oで表わさ
れる。(ただし、MはTMA、Na及びKイオンで
M2Oの係数は1前後で変動する。xは0〜10で
ある。)TMAイオンはオフレタイト結晶中に陽
イオンとして存在し、オフレタイトを500〜600℃
で焼成するとTMAイオンは分解脱離しHイオン
となり、オフレタイト中に残存する。
TMAオフレタイトは第1図に示すように粉末
X線回折図からも他のゼオライトと明瞭に区別で
きる。特に、化学組成、結晶構造がオフレタイト
に類似しているゼオライトにエリオナイト、ゼオ
ライトT、ZSM−34があるが、X線回折図上
“odd l line”と呼ばれる2θ=9.6度、16.6度、
21.4度、31.9度(銅のKα二重線による測定)のピ
ークがオフレタイトの場合は無いことからこれら
と明確に区別できる。
一般に、ゼオライトを分子篩、イオン交換体、
触媒として用いる場合、ゼオライト原粉末を造粒
成型して使用することが多い。この場合、ゼオラ
イトの持つ機能即ち分離選択性、吸着速度、交換
速度、活性等を高めるためには原粉末の粒子径が
微細であることが必須である。このことはゼオラ
イト粒子内での吸着分子、イオンの拡散速度の増
大が前記したゼオライトの機能の向上に寄与する
ことが説明できる。
又、ある種のゼオライトに、これと異なるゼオ
ライト(不純分として)が混在したものは、その
中に異なる大きさの細孔が共存することになり、
例えば、これを分子篩として用いる場合、目的と
する分子の単位重量ゼオライト当りの分離性が甚
だ悪くなる。又、これを触媒として用いる場合ゼ
オライト結晶内の細孔が反応の場であるが故に有
する形状選択性(細孔よりも大きな分子は細孔に
入り得ず、従つて反応せず、又このために細孔よ
り大きな分子は生成しないという触媒特性)が損
なわれることになる。従つて、ゼオライトを分子
篩や触媒として利用する場合、混合による複合効
果を期待する場合以外は、異種ゼオライトを含ま
ない高純度なそして微細な粒径を持つゼオライト
が望まれる。このことについては、オフレタイト
についても例外ではない。TMAオフレタイトの
合成法は、従来から知られている。例えば、特公
昭49−27280号公報には反応混合物を98℃で4〜
8日間維持し、TMAオフレタイトを得る方法が
開示されているが、この方法では、結晶化に長時
間を要する。又、米国特許第3578398号公報には、
反応混合物を室温下に15時間以上、特に24時間〜
7目間保持(熟成)することによつて微細な
TMAオフレタイトを製造する方法が開示されて
いる。しかし、この方法では確かに微細な結晶を
得ることはできるが、熟成に長時間を要し、必ず
しも工業的、経済的な方法とは言えない。又、同
公報には、比較的高い温度で結晶化することによ
り、結晶化時間を短縮し得ることが開示されてい
るが、高温度による結晶化は、生成物中にアナル
サイムやソーダライト等の不純物の混入が考えら
れ必ずしも好ましい方法ではない。本発明者ら
は、これら従来の合成法の問題を解決すべく鋭意
研究の結果、本発明を見出したもので、本発明は
従来法のような長時間の熟成手段を必要とせず
に、微細でかつ不純物を含まないTMAオフレタ
イトを合成する方法を提供することを目的とする
ものである。
本発明を更に説明する。一般的に、ゼオライト
を合成する上で生成物の性質を左右する重要な因
子がいくつかある。それらの内でも、反応混合物
の組成、結晶化の温度、時間が特に重要であるが
反応混合物を結晶化温度にどのような状態で維持
するかも極めて重要な因子である。反応混合物組
成がたとえ適切であつても、結晶化中に撹拌を施
すと目的とする性質のゼオライトが得られないこ
とを本発明者らはしばしば経験している。それは
モルデナイト、ソーダライト、アナルサイムなど
の限られた種類のゼオライト以外は結晶系で準安
定相として存在する為に僅かな環境変化でも結晶
化に影響すると考えられるからである。従つて、
従来ゼオライトの合成法は撹拌を全く行わない、
いわゆる静置法が主流とされて来た。
本発明は、ゼオライトの結晶化時の撹拌条件に
関して種々の検討を重ねた結果得た知見に基づく
ものである。
即ち、本発明者らはSiO2、Al2O3、Na2O、
K2O、(TMA)2O及びH2Oを含む反応混合物を特
別の熟成工程を経ることなく、加熱結晶化し、
TMAオフレタイトを製造する際、温度、H2O/
SiO2モル比、(TMA)2/SiO2モル比、結晶化時
の撹拌強度等の条件と生成物との間には複雑な関
係が有つて、限定された条件でのみ微細かつ高純
度のTMAオフレタイトを得るとの知見を得た。
その限定条件とは、(1)反応混合物組成がH2O/
SiO2=10〜70であり、かつ(TMA)2O/SiO2=
0.008〜0.04を満足していること、(2)結晶化温度
が130〜180℃であること、(3)その温度において周
速0.3m/sec以上で撹拌することである。これら
の(1)〜(3)を満足して初めて微細でかつ不純物を含
まないTMAオフレタイトを僅か数分〜20時間の
結晶化時間で得ることができる。
本発明を実施する為に必要な反応混合物は、
TMAオフレタイトを合成できる組成であれば特
に限定されないが、前記したように少なくとも
H2O/SiO2=10〜70で、かつ(TMA)2O/SiO2
=0.008〜0.04であることが必須であり、好まし
くはH2O/SiO2=12〜50、(TMA)2O/SiO2=
0.01〜0.03である。H2O/SiO2が10未満であると
後述する撹拌による効果が殆ど無くなり、又70を
超えると不純物が生成しやすくなる。
(TMA)2O/SiO2が0.008未満であると生成物の
結晶化が不充分となつたり、不純物が生成し、
0.04を超えると結晶化度が低下してくる。本発明
で用いるSiO2源、Al2O3源、Na2O源、K2O源、
(TMA)2O源としては、特に限定されないが、経
済的見地から、SiO2源は非晶質固体シリカ、水
ガラス;Al2O3源はアルミン酸ソーダ、Al
(OH)3;Na2O源はNaOH;K2O源はKOH;
(TMA)2O源は水酸化物あるいはハロゲン化物が
それぞれ望ましい。各原料の混合法は特に限定さ
れないが、Al2O3源を含むアルカリ源をすべて混
合した後にSiO2源を混合するのが好ましい。混
合した反応混合物は熟成することなく直ちに結晶
化操作を行う。ここで言う熟成とは、従来法のよ
うな10数時間以上の長時間熟成を指し、ゼオライ
ト合成工程上必然的に生ずる短時間の放置時間等
は含まない。結晶化温度は本発明を実施する上で
130〜180℃であることが必須である。前記温度が
130℃未満では結晶化に長時間を要し、180℃を超
えると不純物が混在してくるばかりか微細な結晶
が得られない。本発明に於ける結晶化温度は反応
混合物の沸点以上であるので密封容器で行う必要
があり、自制圧下か又はチツ素等の不活性ガスに
よる加圧下でも行うことができる。本発明では結
晶化時の撹拌が特に重要である。即ち、撹拌に用
いる撹拌羽根の回転時の最大直径をd(m)、撹拌
速度をv(rpm)としたときに、(π)(d)(v)/(60
)で
定義される周速(m/sec)が0.3m/sec以上で
あることが必須である。前記撹拌は(1)結晶化時間
を短縮する、(2)結晶を微細にする、(3)不純物の生
成を抑制する。などの効果を有している。
本発明法において撹拌が重要であることは、単
に結晶系の伝熱を助けるだけではなく、核生成、
結晶成長に撹拌操作が微妙に影響していることに
よると思われる。本発明で望ましい撹拌の度合は
前記した周速が0.3m/sec以上であるが、更に望
ましくは、0.4〜10m/secである。前記周速が0.3
m/secに満たない場合は、本発明の効果が得ら
れず、10m/secを超えると反応混合物が結晶へ
と変化する中間生成物、即ち前駆物質がこの段階
で破壊されるものと思われ、結晶化が不完全とな
る。本発明で用いる結晶化槽と撹拌羽根の形、大
きさは特に限定されないが、本発明を効果的に実
施する為には、前記した撹拌羽根の最大直径が結
晶化槽の内径の1/4以上であることが望ましい。
又、結晶化時間は、本発明法の効果の1つでもあ
るが、結晶化温度に昇温後、僅か数分〜20時間で
充分である。
本発明法によつて得たTMAオフレタイトは、
冷却後、固液分離、洗浄、乾燥等公知法によつて
後処理される。又、同オフレタイトは500〜600℃
にて焼成後、又は前記焼成後更に適当に陽イオン
交換した後種々の用途に供することができる。例
えば、脱水剤、吸着分離剤、炭化水素の転化触媒
として有効に利用できる。
以下、実施例で本発明を説明するが、これら実
施例にのみ限定されるものではない。
実施例 1
非晶質固体シリカ(日本シリカ工業社製ホワイ
トカーボン)、アルミン酸ソーダ水溶液
(Na2O18.8w%、Al2O321.8wt%)、固型NaOH、
固型KOH、テトラメチルアンモニウムハイドロ
オキサイド及び純水とから、次の式で表わされる
反応混合物を作つた。
0.39(TMA)2O・5.75Na2O・1.15K2O・
Al2O3・17.6SiO2・325H2O
尚、混合順序は純水にまずNaOH、KOHを溶
解し、次にアルミン酸ソーダ水溶液を加え、最後
に撹拌しながら非晶質固体シリカを加えた。
4000gの反応混合物を撹拌機付きのオートクレ
ーブに入れ170℃で結晶化した。撹拌羽根はター
ビン型で回転した際の最大直径がオートクレーブ
内径の1/2であつた。撹拌強度(周速)は1m/
sec、反応混合物調製後(シリカ添加終了後)か
らオートクレーブへ仕込むまでの時間は約1時間
であつた。オートクレーブの昇温時間(加熱を開
始してから結晶化温度170℃になるまでの時間)
は約2時間であつた。170℃に5分維持した後、
冷却し固型物を別し、充分水洗後110℃で2時
間乾燥した。生成物のX線回折図を第1図に示す
が、このものは高純度のTMAオフレタイトであ
り、不純物は認められなかつた。又、結晶の粒径
は殆んどが1μ以下の微細な粒子であつた。
実施例2〜5、比較例1〜8
200gの反応混合物を仕込み、結晶化温度、結
晶化時間、撹拌速度を変えた以外は実施例1と同
様に行い第1表にその結果を示す。又、比較例4
で得た結晶のX線回折図を第2図に示す。
実施例6、比較例9〜10
反応混合物の組成を変え、200gの反応混合物
を仕込んだ以外は実施例1と同様に行つた。結果
を第2表に示す。
The present invention relates to an improved method for synthesizing zeolite, and in particular provides a method for synthesizing fine and highly pure offretite crystals, which is a type of zeolite, in a short time. Zeolite, which means boiling stone in Greek, is a crystalline aluminosilicate containing zeolite water. Its basic structure is a SiO 4 tetrahedron formed around silicon with four oxygen atoms placed at the vertices.
This silicon was replaced by aluminum.
The AlO 4 tetrahedron has an atomic ratio of O/(Al+Si) of 2.
They are arranged in a regular three-dimensional manner while sharing oxygen so that The negative charge of the AlO 4 tetrahedron is balanced by the inclusion of alkali metal and alkaline earth metal cations. Furthermore, pores of various sizes are formed depending on the arrangement of the tetrahedrons, and water molecules and exchangeable cations usually exist in the pores. When zeolite is dehydrated or the cations in zeolite are exchanged with other appropriate cations, it can be used as a so-called molecular sieve that has the function of trapping specific molecules in the pores, or it can be reacted only within the pores. It is an industrially valuable substance that is used in various fields, such as as a catalyst, an ion exchanger, and a catalyst carrier. Zeolites are known to have various crystal structures, and these can be distinguished by powder X-ray diffraction patterns. Zeolites also exist naturally, and now naturally occurring zeolites can also be obtained synthetically. Also, zeolites that do not exist naturally can now be synthesized. OFFRETITE, a type of zeolite, also exists in nature, has a hexagonal crystal structure (lattice constants a: 13.3A, c: 7.59A), and has pores that can adsorb cyclohexane. In addition, offretite uses tetramethylammonium ion (hereinafter TMA) in its synthesis reaction system.
The obtained offretite is also called "TMA offretite" because it can be synthesized in the presence of ions (referred to as ions). The chemical composition of this substance is
It is represented by M2O.Al2O3 .( 5-10 ) SiO2.xH2O . (However, M is TMA, Na and K ions.
The coefficient of M 2 O fluctuates around 1. x is 0-10. ) TMA ions exist as cations in offretite crystals, and the offretite is heated to 500-600℃.
When fired, TMA ions are decomposed and released to become H ions, which remain in the offretite. As shown in Figure 1, TMA offretite can be clearly distinguished from other zeolites from its powder X-ray diffraction pattern. In particular, zeolites whose chemical composition and crystal structure are similar to offretite include erionite, zeolite T, and ZSM-34, but they have 2θ = 9.6 degrees, 16.6 degrees, which is called the "odd line" on the X-ray diffraction diagram.
Offretite has no peaks at 21.4 degrees and 31.9 degrees (measured using the Kα doublet of copper), so it can be clearly distinguished from these. Generally, zeolites are used as molecular sieves, ion exchangers,
When used as a catalyst, raw zeolite powder is often granulated and used. In this case, in order to enhance the functions of zeolite, ie, separation selectivity, adsorption rate, exchange rate, activity, etc., it is essential that the raw powder has a fine particle size. This can be explained by the fact that the increase in the diffusion rate of adsorbed molecules and ions within the zeolite particles contributes to the improvement of the above-mentioned functions of the zeolite. Also, when a certain type of zeolite is mixed with a different zeolite (as an impurity), pores of different sizes coexist within it.
For example, when this is used as a molecular sieve, the separation of target molecules per unit weight of zeolite becomes extremely poor. In addition, when using this as a catalyst, it has shape selectivity because the pores in the zeolite crystal are the reaction sites (molecules larger than the pores cannot enter the pores and therefore do not react; The catalytic property of not producing molecules larger than the pores will be impaired. Therefore, when using zeolite as a molecular sieve or catalyst, a zeolite with high purity and fine particle size that does not contain foreign zeolites is desired, unless a composite effect is expected by mixing. Offretite is no exception to this matter. Methods for synthesizing TMA offretite have been known for a long time. For example, in Japanese Patent Publication No. 49-27280, the reaction mixture was
A method is disclosed in which TMA offretite is obtained by maintaining it for 8 days, but this method requires a long time for crystallization. Also, in U.S. Patent No. 3578398,
The reaction mixture is kept at room temperature for at least 15 hours, especially for ~24 hours.
By holding (aging) for 7 days, fine
A method of making TMA offretite is disclosed. However, although fine crystals can certainly be obtained with this method, it takes a long time for ripening, and it cannot necessarily be said to be an industrial or economical method. In addition, the same publication discloses that crystallization time can be shortened by crystallizing at a relatively high temperature; however, crystallization at a high temperature may cause analcyme, sodalite, etc. This is not necessarily a preferable method because of the possibility of contamination with impurities. The present inventors have discovered the present invention as a result of intensive research to solve the problems of these conventional synthesis methods. The purpose of the present invention is to provide a method for synthesizing TMA offretite that is free from impurities. The present invention will be further explained. In general, when synthesizing zeolites, there are several important factors that influence the properties of the product. Among these, the composition of the reaction mixture, the temperature and time of crystallization are particularly important, but the state in which the reaction mixture is maintained at the crystallization temperature is also an extremely important factor. The inventors have often experienced that, even if the reaction mixture composition is appropriate, a zeolite with the desired properties cannot be obtained if agitation is applied during crystallization. This is because, except for limited types of zeolites such as mordenite, sodalite, and analcyme, zeolites exist as metastable crystalline phases, so even slight environmental changes are thought to affect crystallization. Therefore,
Conventional zeolite synthesis methods do not involve stirring at all.
The so-called stationary method has become mainstream. The present invention is based on knowledge obtained as a result of various studies regarding stirring conditions during crystallization of zeolite. That is, the present inventors used SiO 2 , Al 2 O 3 , Na 2 O,
A reaction mixture containing K 2 O, (TMA) 2 O and H 2 O is heated and crystallized without going through a special aging process,
When producing TMA offretite, temperature, H2O /
There is a complicated relationship between the SiO 2 molar ratio, (TMA) 2 /SiO 2 molar ratio, conditions such as stirring intensity during crystallization, and the product, and only under limited conditions can fine and high-purity crystals be produced. We obtained the knowledge that TMA offretite can be obtained.
The limiting conditions are (1) the reaction mixture composition is H 2 O/
SiO 2 = 10 to 70, and (TMA) 2 O/SiO 2 =
0.008 to 0.04, (2) the crystallization temperature is 130 to 180°C, and (3) stirring is performed at a circumferential speed of 0.3 m/sec or more at that temperature. Only when these (1) to (3) are satisfied can TMA offretite, which is fine and does not contain any impurities, be obtained in a crystallization time of only a few minutes to 20 hours. The reaction mixture necessary to carry out the invention is:
The composition is not particularly limited as long as it can synthesize TMA offretite, but as mentioned above, at least
H 2 O/SiO 2 = 10 to 70, and (TMA) 2 O/SiO 2
= 0.008 to 0.04, preferably H2O / SiO2 = 12 to 50, (TMA) 2O / SiO2 =
It is 0.01-0.03. When H 2 O/SiO 2 is less than 10, the effect of stirring, which will be described later, is almost lost, and when it exceeds 70, impurities are likely to be generated.
(TMA) 2 O/SiO 2 less than 0.008 may result in insufficient crystallization of the product or the formation of impurities.
When it exceeds 0.04, the degree of crystallinity decreases. SiO 2 source, Al 2 O 3 source, Na 2 O source, K 2 O source used in the present invention,
(TMA) 2 O sources are not particularly limited, but from an economical point of view, SiO 2 sources include amorphous solid silica, water glass; Al 2 O 3 sources include sodium aluminate, Al
(OH) 3 ; Na 2 O source is NaOH; K 2 O source is KOH;
(TMA) 2 Preferably, the O source is a hydroxide or a halide. Although the method of mixing each raw material is not particularly limited, it is preferable to mix the SiO 2 source after all the alkali sources including the Al 2 O 3 source are mixed. The mixed reaction mixture is immediately subjected to a crystallization operation without being aged. The term "ripening" as used herein refers to long-term aging of ten or more hours as in conventional methods, and does not include short-term standing times that inevitably occur during the zeolite synthesis process. The crystallization temperature is determined in carrying out the present invention.
It is essential that the temperature is 130-180°C. The temperature is
If it is less than 130°C, it will take a long time to crystallize, and if it exceeds 180°C, not only will impurities be mixed in, but fine crystals will not be obtained. Since the crystallization temperature in the present invention is higher than the boiling point of the reaction mixture, it is necessary to carry out the crystallization in a sealed container, and it can also be carried out under self-contained pressure or under pressure with an inert gas such as nitrogen. In the present invention, stirring during crystallization is particularly important. In other words, when the maximum diameter during rotation of the stirring blade used for stirring is d (m) and the stirring speed is v (rpm), (π) (d) (v) / (60
) It is essential that the circumferential speed (m/sec) defined as 0.3 m/sec or more is required. The above stirring (1) shortens the crystallization time, (2) makes the crystals finer, and (3) suppresses the formation of impurities. It has the following effects. The importance of stirring in the method of the present invention is that it not only assists in heat transfer in the crystal system, but also in nucleation and
This seems to be due to the subtle influence of the stirring operation on crystal growth. In the present invention, the desired degree of stirring is such that the circumferential speed is 0.3 m/sec or more, more preferably 0.4 to 10 m/sec. The peripheral speed is 0.3
If it is less than 10 m/sec, the effect of the present invention cannot be obtained, and if it exceeds 10 m/sec, it is thought that the intermediate product that transforms the reaction mixture into crystals, that is, the precursor, is destroyed at this stage. , crystallization becomes incomplete. The shape and size of the crystallization tank and stirring blade used in the present invention are not particularly limited, but in order to effectively carry out the present invention, the maximum diameter of the stirring blade described above must be 1/4 of the inner diameter of the crystallization tank. The above is desirable.
Further, the crystallization time is one of the effects of the method of the present invention, and a period of only a few minutes to 20 hours after raising the temperature to the crystallization temperature is sufficient. TMA offretite obtained by the method of the present invention is
After cooling, it is post-treated by known methods such as solid-liquid separation, washing, and drying. Also, the offretite temperature is 500~600℃
After firing, or after the firing, it can be used for various purposes after being subjected to appropriate cation exchange. For example, it can be effectively used as a dehydrating agent, an adsorption/separation agent, and a hydrocarbon conversion catalyst. The present invention will be explained below with reference to Examples, but it is not limited only to these Examples. Example 1 Amorphous solid silica (white carbon manufactured by Nippon Silica Kogyo Co., Ltd.), aqueous sodium aluminate solution (Na 2 O 18.8w%, Al 2 O 3 21.8wt%), solid NaOH,
A reaction mixture represented by the following formula was prepared from solid KOH, tetramethylammonium hydroxide, and pure water. 0.39(TMA) 2 O・5.75Na 2 O・1.15K 2 O・
Al 2 O 3・17.6SiO 2・325H 2 O The mixing order was as follows: First, NaOH and KOH were dissolved in pure water, then an aqueous solution of sodium aluminate was added, and finally, amorphous solid silica was added while stirring. . 4000 g of the reaction mixture was placed in an autoclave equipped with a stirrer and crystallized at 170°C. The stirring blade was a turbine type whose maximum diameter when rotating was 1/2 of the autoclave's inner diameter. Stirring intensity (peripheral speed) is 1m/
sec, the time from the preparation of the reaction mixture (after the addition of silica) to the time it was charged into the autoclave was about 1 hour. Autoclave heating time (time from starting heating until crystallization temperature reaches 170℃)
It took about 2 hours. After maintaining at 170℃ for 5 minutes,
After cooling, the solid matter was separated, thoroughly washed with water, and then dried at 110°C for 2 hours. The X-ray diffraction pattern of the product is shown in Figure 1, and it was a highly pure TMA offretite with no impurities observed. In addition, most of the crystals were fine particles with a particle size of 1 μ or less. Examples 2 to 5, Comparative Examples 1 to 8 The same procedure as in Example 1 was conducted except that 200 g of the reaction mixture was charged and the crystallization temperature, crystallization time, and stirring speed were changed, and the results are shown in Table 1. Also, comparative example 4
Figure 2 shows the X-ray diffraction pattern of the crystal obtained in . Example 6, Comparative Examples 9-10 The same procedure as in Example 1 was carried out except that the composition of the reaction mixture was changed and 200 g of the reaction mixture was charged. The results are shown in Table 2.
【表】【table】
第1図は実施例1によつて得られた結晶の、又
第2図は比較例4で得た結晶の粉末X線回折図で
ある。銅のKα二重線を用いて測定した。
FIG. 1 is a powder X-ray diffraction pattern of the crystal obtained in Example 1, and FIG. 2 is a powder X-ray diffraction pattern of the crystal obtained in Comparative Example 4. It was measured using a copper Kα doublet.
Claims (1)
(TMAはテトラメチルアンモニウムイオン)、
H2Oからなる反応混合物を結晶化しゼオライト
を合成する方法において、H2O/SiO2モル比が
10〜70、(TMA)2O/SiO2モル比が0.008〜0.04を
満足する反応混合物を周速0.3m/sec以上で撹拌
しながら温度130〜180℃で結晶化することを特徴
とするゼオライトの合成法。 2 結晶化時間が20時間以下である特許請求の範
囲第1項記載の方法。[Claims] 1 SiO 2 , Al 2 O 3 , Na 2 O, K 2 O, (TMA) 2 O
(TMA is tetramethylammonium ion),
In the method of synthesizing zeolite by crystallizing a reaction mixture consisting of H 2 O, the H 2 O/SiO 2 molar ratio is
10 to 70, (TMA) 2 O/SiO 2 A zeolite characterized by crystallizing at a temperature of 130 to 180° C. while stirring a reaction mixture having a molar ratio of 0.008 to 0.04 at a circumferential speed of 0.3 m/sec or more. synthesis method. 2. The method according to claim 1, wherein the crystallization time is 20 hours or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1478382A JPS58135123A (en) | 1982-02-03 | 1982-02-03 | Synthesis of zeolite |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1478382A JPS58135123A (en) | 1982-02-03 | 1982-02-03 | Synthesis of zeolite |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS58135123A JPS58135123A (en) | 1983-08-11 |
JPH0339972B2 true JPH0339972B2 (en) | 1991-06-17 |
Family
ID=11870644
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1478382A Granted JPS58135123A (en) | 1982-02-03 | 1982-02-03 | Synthesis of zeolite |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS58135123A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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EP2354091B1 (en) * | 2010-02-06 | 2017-11-29 | Cognis IP Management GmbH | Silicate solutions stable in storage |
CN104030313B (en) * | 2014-05-26 | 2016-08-24 | 中国海洋石油总公司 | A kind of method of synthesizing submicron type T molecular sieve |
-
1982
- 1982-02-03 JP JP1478382A patent/JPS58135123A/en active Granted
Also Published As
Publication number | Publication date |
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JPS58135123A (en) | 1983-08-11 |
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