化工学报
化工學報
화공학보
CIESC Jorunal
2015年
9期
3428-3436
,共9页
固体酸催化剂%果糖%乳酸甲酯%乙酰丙酸甲酯%B酸位%L酸位
固體痠催化劑%果糖%乳痠甲酯%乙酰丙痠甲酯%B痠位%L痠位
고체산최화제%과당%유산갑지%을선병산갑지%B산위%L산위
solid acid catalyst%fructose%methyl lactate%methyl levulinate%Br?nsted acid sites%Lewis acid sites
制备了 γ-Al2O3、HZSM-5、SnOPO4、SnZrOPO4(1:1)、SO42?/ZrO2 5 种不同的固体酸催化剂,采用 NH3 程序升温脱附、吡啶原位吸附红外对催化剂进行了表征.考察了固体酸催化果糖在甲醇中转化的催化性能,结果表明,果糖的转化率均高于 98%,产物分布与固体酸表面 L 酸、B 酸酸量具有显著的相关性,乳酸甲酯的收率随着L 酸量的减少而降低,L 酸催化剂 γ-Al2O3 催化,主产物只有乳酸甲酯,收率为 24.4%.而 L 酸位和 B 酸位共存的固体酸,产物中有乳酸甲酯、乙酰丙酸甲酯,并且乙酰丙酸甲酯的收率随着 B 酸量的增多而升高.最后考察了典型 L 酸 γ-Al2O3 及 B 酸 L 酸共存的固体酸 HZSM-5 不同反应时间的产物分布,结合气相-质谱联用对产物定性分析,得出了果糖转化过程 L 酸位催化和 B 酸位催化的反应路径.
製備瞭 γ-Al2O3、HZSM-5、SnOPO4、SnZrOPO4(1:1)、SO42?/ZrO2 5 種不同的固體痠催化劑,採用 NH3 程序升溫脫附、吡啶原位吸附紅外對催化劑進行瞭錶徵.攷察瞭固體痠催化果糖在甲醇中轉化的催化性能,結果錶明,果糖的轉化率均高于 98%,產物分佈與固體痠錶麵 L 痠、B 痠痠量具有顯著的相關性,乳痠甲酯的收率隨著L 痠量的減少而降低,L 痠催化劑 γ-Al2O3 催化,主產物隻有乳痠甲酯,收率為 24.4%.而 L 痠位和 B 痠位共存的固體痠,產物中有乳痠甲酯、乙酰丙痠甲酯,併且乙酰丙痠甲酯的收率隨著 B 痠量的增多而升高.最後攷察瞭典型 L 痠 γ-Al2O3 及 B 痠 L 痠共存的固體痠 HZSM-5 不同反應時間的產物分佈,結閤氣相-質譜聯用對產物定性分析,得齣瞭果糖轉化過程 L 痠位催化和 B 痠位催化的反應路徑.
제비료 γ-Al2O3、HZSM-5、SnOPO4、SnZrOPO4(1:1)、SO42?/ZrO2 5 충불동적고체산최화제,채용 NH3 정서승온탈부、필정원위흡부홍외대최화제진행료표정.고찰료고체산최화과당재갑순중전화적최화성능,결과표명,과당적전화솔균고우 98%,산물분포여고체산표면 L 산、B 산산량구유현저적상관성,유산갑지적수솔수착L 산량적감소이강저,L 산최화제 γ-Al2O3 최화,주산물지유유산갑지,수솔위 24.4%.이 L 산위화 B 산위공존적고체산,산물중유유산갑지、을선병산갑지,병차을선병산갑지적수솔수착 B 산량적증다이승고.최후고찰료전형 L 산 γ-Al2O3 급 B 산 L 산공존적고체산 HZSM-5 불동반응시간적산물분포,결합기상-질보련용대산물정성분석,득출료과당전화과정 L 산위최화화 B 산위최화적반응로경.
Catalytic conversion of fructose directly into alkyl lactate is one of the effective ways for use of biomass to produce high value-added chemicals. Research shows that one of main factors influencing the alkyl lactate yield is Lewis and Br(o)nsted acid sites on the surface of solid acid catalysts. A series of solid acid catalysts with different acid sites and concentration is prepared, including γ-Al2O3, HZSM-5 zeolite, SnOPO4, SnZrOPO4(1:1), and SO42-/ZrO2. All of catalysts was characterized by using NH3 temperature-programmed desorption(NH3-TPD) and infrared spectroscopy with pyridine adsorption(Py-FTIR) techniques to figure out their total acid concentration, Lewis and Br(o)nsted acid concentrations. The catalytic conversion of fructose in methanol over the five solid acid catalysts was studied. The results showed that the conversions of fructose can be higher than 98%; product distribution obtained depends greatly on Lewis and Br?nsted acid amounts; and yield of methyl lactate lessened with the decrease of Lewis acid concentration. For γ-Al2O3 catalyst that contains only Lewis acid sites, the yields of methyl lactate achieved is 24.4%, while for these solid acid catalyst that contain both Lewis and Br(o)nsted acid sites, the product obtained is not only methyl lactate but also methyl levulinate, and yield of methyl levulinate improves with increase of Br(o)nsted acid concentration. Finally, the product distribution from the reactions catalyzed by typical Lewis acid solid catalyst γ-Al2O3 and HZSM-5 catalyst with both Br(o)nsted and Lewis acid sites at different reaction time was investigated. Combined with the qualitative analysis obtained by gas chromatography-mass spectrometry(GC-MS), the reaction pathway for fructose conversion catalyzed by Lewis and Br(o)nsted acid sites was proposed.
