Lithium hydride (LiH), ib qho khoom sib xyaw ua ke yooj yim uas muaj lithium thiab hydrogen, sawv cev rau cov khoom siv tseem ceeb hauv kev tshawb fawb thiab kev lag luam txawm tias nws cov mis yooj yim. Zoo li cov siv lead ua tawv, xiav-dawb, cov ntsev inorganic no muaj kev sib xyaw ua ke ntawm cov tshuaj lom neeg thiab cov khoom siv lub cev uas tau ua kom nws lub luag haujlwm hauv ntau yam thiab feem ntau yog qhov tseem ceeb, xws li kev tsim cov tshuaj zoo mus rau kev siv tshuab tshiab. Nws txoj kev taug kev los ntawm kev xav paub hauv chaw kuaj mob mus rau cov khoom siv uas ua rau muaj cov thev naus laus zis siab heev qhia txog nws qhov kev siv tau zoo heev.
Cov Khoom Tseem Ceeb thiab Kev Xav Txog Kev Tuav
Lithium hydride yog tus cwj pwm los ntawm nws qhov chaw yaj siab (kwv yees li 680 ° C) thiab qhov ceev qis (kwv yees li 0.78 g / cm³), ua rau nws yog ib qho ntawm cov khoom sib xyaw ionic sib xyaw uas sib dua tshaj plaws. Nws crystallizes hauv cov qauv pob zeb-ntsev cubic. Txawm li cas los xij, nws qhov tshwj xeeb tshaj plaws, thiab qhov tseem ceeb hauv nws cov kev xav tau kev tuav, yog nws qhov ua haujlwm hnyav nrog cov dej noo. LiH yog hygroscopic heev thiab flammable hauv cov dej noo. Thaum kov dej lossis txawm tias cov av noo hauv huab cua, nws dhau los ua qhov tshuaj tiv thaiv muaj zog thiab exothermic: LiH + H₂O → LiOH + H₂. Qhov tshuaj tiv thaiv no tso tawm cov roj hydrogen sai sai, uas yog flammable heev thiab ua rau muaj kev phom sij loj heev yog tias tsis tswj hwm. Yog li ntawd, LiH yuav tsum tau tuav thiab khaws cia rau hauv cov xwm txheej inert nruj me ntsis, feem ntau nyob rau hauv huab cua ntawm argon qhuav lossis nitrogen, siv cov txheej txheem tshwj xeeb xws li gloveboxes lossis Schlenk kab. Qhov kev ua haujlwm no, thaum muaj kev sib tw tuav, kuj yog qhov chaw ntawm nws cov txiaj ntsig ntau.
Cov Ntawv Siv Hauv Kev Lag Luam thiab Tshuaj Lom Zem
1. Cov Khoom Siv Ua Ntej Rau Cov Hydrides Sib Xyaws: Ib qho ntawm kev siv LiH tseem ceeb tshaj plaws hauv kev lag luam yog ua cov khoom siv pib tseem ceeb rau kev tsim cov Lithium Aluminium Hydride (LiAlH₄), uas yog cov tshuaj reagent tseem ceeb hauv cov organic thiab inorganic chemistry. LiAlH₄ yog synthesized los ntawm kev cuam tshuam LiH nrog aluminium chloride (AlCl₃) hauv cov kuab tshuaj ethereal. LiAlH₄ nws tus kheej yog ib qho tshuaj txo qis muaj zog heev thiab ntau yam, tsis tseem ceeb rau kev txo cov pab pawg carbonyl, carboxylic acids, esters, thiab ntau lwm yam pab pawg ua haujlwm hauv kev lag luam tshuaj, cov tshuaj zoo, thiab kev tsim cov polymer. Yog tsis muaj LiH, kev tsim cov LiAlH₄ loj yuav tsis yooj yim.
2. Kev Tsim Silane: LiH ua lub luag haujlwm tseem ceeb hauv kev tsim cov silane (SiH₄), uas yog ib qho tseem ceeb rau cov silicon ntshiab siv rau hauv cov khoom siv semiconductor thiab cov roj teeb hnub ci. Txoj kev lag luam tseem ceeb yog kev sib xyaw ntawm LiH nrog silicon tetrachloride (SiCl₄): 4 LiH + SiCl₄ → SiH₄ + 4 LiCl. Silane qhov kev xav tau siab purity ua rau cov txheej txheem LiH no tseem ceeb rau kev lag luam hluav taws xob thiab photovoltaics.
3. Tus Neeg Sawv Cev Txo Zog: Ncaj qha, LiH ua haujlwm ua tus neeg sawv cev txo zog hauv kev tsim cov organic thiab inorganic. Nws lub zog txo zog muaj zog (tus qauv txo peev xwm ~ -2.25 V) tso cai rau nws kom txo ntau yam hlau oxides, halides, thiab cov organic sib xyaw tsis muaj zog hauv qab qhov kub siab lossis hauv cov txheej txheem tshwj xeeb. Nws muaj txiaj ntsig zoo rau kev tsim cov hlau hydrides lossis txo cov pab pawg ua haujlwm uas tsis yooj yim nkag mus rau qhov twg cov tshuaj reagents tsis ua haujlwm.
4. Tus Neeg Sawv Cev Condensation hauv Organic Synthesis: LiH pom tias siv tau ua tus neeg sawv cev condensation, tshwj xeeb tshaj yog hauv cov tshuaj tiv thaiv zoo li Knoevenagel condensation lossis aldol-type reactions. Nws tuaj yeem ua haujlwm ua lub hauv paus rau deprotonate acidic substrates, pab txhawb kev tsim cov carbon-carbon bond. Nws qhov zoo feem ntau yog nyob rau hauv nws cov kev xaiv thiab kev yaj ntawm cov ntsev lithium tsim ua cov khoom byproducts.
5. Qhov Chaw Hydrogen Uas Siv Tau Yooj Yim: Qhov sib xyaw ua ke ntawm LiH nrog dej los tsim cov roj hydrogen ua rau nws yog ib qho chaw zoo rau kev siv hydrogen. Cov khoom no tau raug tshawb nrhiav rau cov ntawv thov xws li cov roj cell (tshwj xeeb tshaj yog rau cov kev xav tau siab, cov khoom siv hluav taws xob ceev), cov tshuab cua sov thaum muaj xwm txheej ceev, thiab kev tsim cov hydrogen hauv chav kuaj uas qhov kev tso tawm tswj tau. Txawm hais tias muaj cov teeb meem ntsig txog kev ua haujlwm ntawm cov tshuaj tiv thaiv, kev tswj cua sov, thiab qhov hnyav ntawm cov khoom siv lithium hydroxide, qhov muaj peev xwm khaws cia hydrogen siab los ntawm qhov hnyav (LiH muaj ~ 12.6 wt% H₂ uas tso tawm tau los ntawm H₂O) tseem ceeb rau cov xwm txheej tshwj xeeb, tshwj xeeb tshaj yog piv rau cov roj compressed.
Cov Khoom Siv Siab Tshaj Plaws: Kev Tiv Thaiv thiab Kev Khaws Cia Zog
1. Khoom Siv Tiv Thaiv Nuclear Uas Tsis Muaj Hnyav: Tshaj li nws cov tshuaj lom neeg, LiH muaj cov khoom zoo heev rau kev siv nuclear. Nws cov khoom sib xyaw ua ke tsawg (lithium thiab hydrogen) ua rau nws zoo heev ntawm kev tswj thiab nqus cov thermal neutrons los ntawm ⁶Li (n,α) ³H ntes cov tshuaj tiv thaiv thiab proton scattering. Qhov tseem ceeb, nws qhov ceev qis heev ua rau nws yog cov khoom siv tiv thaiv nuclear uas tsis muaj zog, muab cov txiaj ntsig zoo dua li cov khoom siv ib txwm muaj xws li txhuas lossis pob zeb hauv cov ntawv thov uas hnyav. Qhov no muaj txiaj ntsig tshwj xeeb hauv aerospace (tiv thaiv cov khoom siv hluav taws xob thiab cov neeg ua haujlwm hauv dav hlau), cov khoom siv neutron uas nqa tau, thiab cov thoob thauj nuclear uas qhov kev txo qhov hnyav yog qhov tseem ceeb. LiH tiv thaiv tau zoo los ntawm cov hluav taws xob tsim los ntawm cov tshuaj tiv thaiv nuclear, tshwj xeeb tshaj yog cov hluav taws xob neutron.
2. Kev Khaws Cia Lub Zog Thermal Rau Cov Tshuab Fais Fab Hauv Chaw: Tej zaum qhov kev siv yav tom ntej thiab kev tshawb fawb tshaj plaws yog kev siv LiH rau kev khaws cia lub zog thermal rau cov tshuab fais fab hauv chaw. Cov haujlwm siab heev hauv chaw, tshwj xeeb tshaj yog cov uas mus deb ntawm Lub Hnub (piv txwv li, mus rau cov ntiaj teb sab nraud lossis lub hli thaum hmo ntuj ntev), xav tau cov tshuab fais fab muaj zog uas tsis muaj kev cuam tshuam los ntawm lub hnub ci. Cov Tshuab Hluav Taws Xob Radioisotope Thermoelectric Generators (RTGs) hloov cov cua sov los ntawm cov radioisotopes uas lwj (xws li Plutonium-238) mus ua hluav taws xob. LiH tab tom raug tshawb nrhiav ua cov khoom siv Thermal Energy Storage (TES) uas koom ua ke nrog cov tshuab no. Lub hauv paus ntsiab lus siv LiH lub cua sov siab heev ntawm kev sib xyaw (melting point ~ 680 ° C, cua sov ntawm kev sib xyaw ~ 2,950 J / g - siab dua li cov ntsev ib txwm muaj xws li NaCl lossis cov ntsev hnub ci). LiH uas yaj tuaj yeem nqus tau ntau yam cua sov los ntawm RTG thaum "them." Thaum lub sijhawm tsaus ntuj lossis lub zog xav tau ntau tshaj plaws, cov cua sov khaws cia raug tso tawm thaum LiH khov kho, tswj qhov kub thiab txias ruaj khov rau cov thermoelectric converters thiab ua kom muaj zog hluav taws xob txuas ntxiv mus, txawm tias qhov chaw cua sov tseem ceeb hloov pauv lossis thaum tsaus ntuj ntev. Kev tshawb fawb tsom mus rau kev sib raug zoo nrog cov ntaub ntawv kaw, kev ruaj khov mus sij hawm ntev hauv qab kev hloov pauv thermal, thiab kev ua kom zoo dua qhov kev tsim qauv rau kev ua haujlwm zoo tshaj plaws thiab kev ntseeg siab hauv qhov chaw nyuaj. NASA thiab lwm lub koom haum chaw pom LiH-based TES ua lub thev naus laus zis tseem ceeb rau kev tshawb nrhiav qhov chaw tob tob thiab kev ua haujlwm ntawm lub hli.
Cov Khoom Siv Ntxiv: Cov Khoom Siv Desiccant
Siv nws txoj kev sib raug zoo nrog dej, LiH kuj ua haujlwm ua cov desiccant zoo heev rau kev ziab cov pa roj thiab cov kuab tshuaj hauv cov ntawv thov tshwj xeeb uas xav tau cov dej noo tsawg heev. Txawm li cas los xij, nws cov tshuaj tiv thaiv tsis rov qab nrog dej (siv LiH thiab tsim cov roj H₂ thiab LiOH) thiab cov teeb meem cuam tshuam txhais tau tias nws feem ntau tsuas yog siv rau qhov twg cov desiccants zoo li molecular sieves lossis phosphorus pentoxide tsis txaus, lossis qhov twg nws cov reactivity ua haujlwm ob lub hom phiaj.
Lithium hydride, nrog nws cov siv lead ua xiav-dawb thiab muaj zog tiv taus dej noo, yog ntau tshaj li ib qho tshuaj lom neeg yooj yim. Nws yog ib qho tseem ceeb hauv kev lag luam rau cov tshuaj reagents tseem ceeb xws li lithium txhuas hydride thiab silane, ib qho muaj zog ncaj qha reductant thiab condensation agent hauv kev tsim, thiab yog qhov chaw ntawm hydrogen portable. Dhau li ntawm cov tshuaj lom neeg ib txwm muaj, nws cov khoom tshwj xeeb - tshwj xeeb tshaj yog nws qhov kev sib xyaw ua ke ntawm qhov ceev qis thiab cov ntsiab lus hydrogen / lithium siab - tau thawb nws mus rau hauv cov thev naus laus zis siab heev. Nws ua haujlwm ua lub tsho tiv thaiv tseem ceeb tiv thaiv hluav taws xob nuclear thiab tam sim no yog nyob rau pem hauv ntej ntawm kev tshawb fawb rau kev ua kom muaj zog rau tiam tom ntej los ntawm kev khaws cia lub zog thermal siab. Thaum xav tau kev tuav pov hwm vim nws qhov xwm txheej pyrophoric, qhov kev siv ntau yam ntawm lithium hydride ua kom nws muaj feem cuam tshuam thoob plaws ntau yam kev tshawb fawb thiab kev tsim kho, los ntawm lub rooj zaum hauv chav kuaj mus rau qhov tob ntawm qhov chaw interplanetary. Nws lub luag haujlwm hauv kev txhawb nqa ob qho tib si kev tsim tshuaj lom neeg tseem ceeb thiab kev tshawb nrhiav qhov chaw ua ntej qhia txog nws qhov txiaj ntsig ntev li cov khoom siv ntawm qhov ceev zog siab thiab kev ua haujlwm tshwj xeeb.
Lub sijhawm tshaj tawm: Lub Xya Hli-30-2025