FCC汽油中的噻吩类硫化物烷基化硫转移反应脱硫

以模型硫化物噻吩与异戊烯的烷基化反应为探针，研究了反应温度、反应压力以及原料中二烯烃杂质对三氯化铝固载改性的磺酸树脂催化剂AlCl3 CT175烷基化性能的影响. 结果表明，在反应温度为100~110℃、反应压力低于3.0 MPa条件下，原料中的二烯烃明显影响催化剂的活性稳定性，这与二烯烃在催化剂表面发生聚合反应结焦有关. 当反应压力高于3.0 MPa时，AlCl3 CT175催化剂催化模型硫化物噻吩与异戊烯的烷基化反应不仅具有很高的活性，噻吩硫化物均接近于完全转化，而且具有较理想的活性稳定性. 以噻吩的甲基取代衍生物相对集中的FCC汽油60~150℃馏分段为原料，在110℃, 3.0 MPa，质量空速2.33 h 1的反应条件下，考察了该馏分段中的噻吩类硫化物与烯烃在AlCl3 CT175催化剂上烷基化反应硫转移脱硫效果，结果表明占总硫98.27%的硫化物参与了烷基化硫转移反应，且该馏分段中的二烯烃含量也得到有效的降低.     

分子筛催化噻吩类硫化物与烯烃烷基化脱硫研究

采用GC—FPD,GC—MS,NH3-TPD及BET等手段,以噻吩,2-甲基噻吩,3-甲基噻吩,2-乙基噻吩及2,5-二甲基噻吩为模型硫合物,异丁烯为烷基化剂,对HZSM-5,Hβ,HM,HY,HMCM-41等分子筛为催化剂催化噻吩类硫化物与异丁烯的烷基化反应进行了研究,并比较不同分子筛的酸强度分布及孔径大小对噻吩类硫化物与异丁烯的烷基化反应性能的影响。结果表明,Hβ,HM,HY,HMCM-41催化剂催化噻吩与异丁烯的烷基化反应在温和的反应条件下(如80℃,常压)即可达到较高的转化率,分子筛催化剂的孔径大小是影响催化括性的关键因素。     

大孔磺酸树脂固载AlCl3用于噻吩与烯烃的烷基化反应

大孔磺酸树脂固载AlCl3是提高树脂催化剂酸强度及其烷基化活性的有效方法，本工作以NKC9, CT175两种磺酸树脂催化剂为载体，采用AlCl3气相固载法分别于不同固载温度及固载时间条件下制得AlCl3–NKC9, AlCl3–CT175催化剂，并对其用于噻吩与异丁烯、异戊烯的烷基化反应活性进行了考察. 结果表明：在固载时间为10~25 h、固载温度为110~120℃条件下，所制得的催化剂在常压、温度60℃、原料(含4300 mg/L噻吩的苯溶液)质量空速为7.5 h–1的反应条件下具有很高的噻吩烷基化活性(噻吩转化率达95%)，且固载AlCl3后的树脂催化剂活性稳定性较固载前有较大程度提高.     

硫化物在OTA催化剂上催化转化性能

考察了催化裂化(FCC)汽油中硫化物和模型硫化物在OTA(Olefin To Aromatics)催化剂上的催化转化性能.结果表明FCC汽油硫化物总脱硫率为86.3 %,其中,硫醚和四氢噻吩的转化率都达到100 %,硫醇硫转化率96.6 %,噻吩硫转化率78.8 %,烷基噻吩转化率85.8 %,苯并噻吩转化率81.4 %.3-甲基噻吩在OTA催化剂上的转化产物中含有小分子(噻吩),异构硫化物(2-甲基噻吩),以及大分子异构硫化物(如2,5-二甲基噻吩、2,4-二甲基噻吩和2,3-二甲基噻吩).烷基噻吩和苯并噻吩硫化物在OTA催化剂上脱硫反应网络一方面含有直接加氢脱硫反应,另一方面经历歧化、异构化和裂解等反应.     

催化精馏用于噻吩硫化物烷基化脱硫的研究

考察了NKC9树脂在固定床反应器中的噻吩烷基化反应性能,制作了由离子交换树脂型固体酸催化剂和不锈钢丝网构成的催化包。在内径30mm、高2200mm的玻璃反应精馏塔内,以NKC9树脂为催化剂,吉1925mg／L噻吩的苯溶液为液体原料,异丁烯为气体原料,对催化精馏用于噻吩硫化物烷基化脱硫的过程进行了研究,考察了异丁烯流量、回流比、进料位置等因素对脱硫率的影响。在异丁烯流量为26mL／min,回流比为3,异丁烯及液体原料分别从第16、15块塔板进料的条件下,塔顶产品中噻吩含量降到49．2mg／L,噻吩的转化率可达97．44％以上。     

固体复合酸催化FCC汽油中噻吩类硫化物烷基化反应动力学

以固体复合酸为催化剂,对汽油中的主要硫化物噻吩(T)、2-甲基噻吩(2-MT)、3-甲基噻吩(3-MT)、2,4-二甲基噻吩(2,4-DMT)烷基化硫转移反应动力学进行研究。结果表明:4种噻吩类硫化物转化率均随反应温度的升高而增大,适宜的动力学考察温度为403.15~433.15 K,当反应温度为433.15 K时,4种硫化物的转化率均达最大,大小依次为2-MT3-MTT2,4-DMT。4种硫化物的烷基化反应动力学方程均符合一级反应速率方程。T,2-MT,3-MT和2,4-DMT的烷基化反应活化能分别为27.92,25.98,45.25和27.29 kJ/mol,指前因子分别为4.427×103,5.316×103,9.98×105和3.91×103h-1。     

噻吩及其衍生物裂化脱硫反应比较

采用半经验的AM1量子化学计算方法和静态理论,分别考察了噻吩、3-甲基噻吩和2,5-二甲基噻吩分子结构特性的不同,从偶极矩、各自垂直于芳香环平面的二维电势能分布曲线和整个分子周围三维电势能分布情况等方面分析了它们在分子筛催化剂表面吸附速度的快慢和生成正碳离子稳定性的高低,进一步比较了噻吩及其衍生物所生成的正碳离子进一步反应的能量变化,从而可判断噻吩及其衍生物裂化脱硫速度的快慢,噻吩及其衍生物裂化脱硫的速度由大到小分别为：2,5-二甲基噻吩、3-甲基噻吩、噻吩。这与在实验室固定床微反装置上以噻吩、3-甲基噻吩和2,5-二甲基噻吩为模型化合物进行实验所得到的结果是一致的。     

大孔磺酸树脂催化FCC汽油烷基化脱硫降烯烃性能的研究

针对大孔磺酸树脂催化FCC汽油组分烷基化脱硫和降烯烃的问题,研究了FCC汽油内部关键组分之间的反应规律。结果表明,NKC-9、D005-Ⅱ、Amberlyst 35和Amberlyst 36 4种大孔磺酸树脂中Amberlyst 36的催化效果最好,最佳反应温度是90℃。在Amberlyst 36催化下,与含硫化合物反应时,烯烃的活性顺序是:异戊烯2,3-二甲基-2-丁烯2,3-二甲基-1-丁烯2-戊烯1-戊烯1-己烯。含硫化合物中硫醇反应活性最高,3-甲基噻吩反应活性大于噻吩。Amberlyst 36催化下,异戊烯、2,3-二甲基-2-丁烯和2-戊烯可以与异戊烷发生烷基化反应,降烯烃效果明显。而1-戊烯、2,3-二甲基-1-丁烯和1-己烯主要是发生自身异构化反应。     

硫化物在纳米HZSM-5催化剂上催化转化性能及机理研究

研究了催化裂化（FCC）汽油中硫化物类型和含量，特别考察了各种硫化物在纳米HZSM-5催化剂上的催化转化性能，并探讨了硫化物的加氢脱硫转化机理。结果表明FCC汽油中硫化物主要为硫醇、噻吩、烷基取代噻吩和苯并噻吩等，其中，烷基取代噻吩占总硫化物的65％-73％。在纳米HZSM-5催化剂作用下，FCC汽油的硫化物都较易被脱除。烷基取代噻吩脱硫机理一方面含有直接加氢脱硫反应路线，另一方面含有裂解反应、烷基化反应和异构化反应路线。     

高选择性地制备单溴代噻吩衍生物

用N-溴代丁二亚酰胺溴化噻吩、2-甲基噻吩、3-甲基噻吩、2,5-二甲基噻吩、苯并噻吩、2-甲基苯并噻吩时,高产率、高区域选择性地得到2-溴噻吩、5-甲基-2-溴噻吩、3-甲基-2-溴噻吩、2,5-二甲基-3-溴噻吩、3-溴苯并噻吩、2-甲基-3-溴苯并噻吩,反应只生成单溴代噻吩衍生物.产物分离方便,同时发现噻吩衍生物的甲基对溴代反应的速度有较大的影响.     

FCC汽油烷基化脱硫研究

分别采用大孔磺酸树脂NKC-9及FCC汽油烷基化催化剂SW—I对FCC汽油进行静态及动态烷基化脱硫研究。结果表明,SW—I烷基化脱硫操作条件更为缓和,其催化活性及寿命均优于NKC-9树脂。在反应温度60℃、反应时间60 min和剂油质量比1:100的条件下,SW—I烷基化脱硫汽油硫含量降至181.7μg·g~(-1),脱硫率63.49%,收率85.30%。SW—I对不同硫含量的FCC汽油均具有一定的脱硫效果,脱硫适应性较强。通过对汽油烷基化反应前后硫化物的分布分析发现,烷基化反应使FCC汽油中的大部分噻吩类化合物反应生成沸点更高的产物,通过蒸馏分离将其除去,达到脱硫目的。     

Gasoline alkylation desulfurization over Amberlyst 35 resin: Influence of methanol and apparent reaction kinetics

Gasoline desulfurization is receiving attention worldwide due to the increasing stringent regulations on sulfur content for environmental protection purpose. As conventional hydrotreating technology leads to significant octane number loss and processing costs, the gasoline alkylation desulfurization process, which consists of weighing down the sulfuric compounds by catalytic alkylation with olefins present in the feed and distillation followed by, is a rather attractive way. In this paper, firstly alkylation of thiophenic compounds was researched over macroporous sulfonic resin Amberlyst 35 in methanol presence to increase the selectivity of catalyst, then kinetics of thiophenic sulfurs alkylation in FCC gasoline was researched without and with methanol. Results found that appropriate methanol (?2 wt.% methanol in model gasoline and ?1 wt.% methanol in FCC gasoline) could inhibit olefins oligomerization significantly without influence on the conversions of thiophenic compounds. The alkylation of thiophenic sulfurs could be described as pseudo first order reaction regardless of the existence of methanol. The introduction of methanol decreases the reaction rate constant and increases the activation energy of alkylation reactions.     

The performance of solid phosphoric acid catalysts and macroporous sulfonic resins on gasoline alkylation desulfurization

Sulfur removal has received increasing attention in recent years primarily for environmental protection purpose. As an attractive technology in the case of gasoline, OATS (olefinic alkylation of thiophenic sulfur) proposed to separate sulfur compounds by distillation after being weighed down by alkylation with olefins in the feed. In this paper, alkylation reactions of thiophenic compounds were studied over solid phosphoric acid catalysts (SPAM and SPAS using MCM-41 and Silicalite-1 zeolite as supporters respectively) and macroporous sulfonic resins (including NKC-9, D005-2 and Amberlyst 35) with model gasoline and FCC (fluid catalytic cracking) gasoline. Results showed that macroporous sulfonic resins showed better performance than solid phosphoric acid catalysts under milder conditions in both feeds. Among the resins, Amberlyst 35 was the most suitable catalyst for the application of catalytic distillation for its good performance at the temperature range of 353-413 K in FCC gasoline. However, the selectivity of isoamylene dimerization over Amberlyst 35 decreased with the temperature, which was harmful to the product yield and catalyst stability. Besides, different activity orders of solid phosphoric acid catalysts in model gasoline and FCC gasoline were explained by combining the acidic properties of the catalysts with the species of olefins in two feeds.     

Comprehensive GC×GC Characterization of the Catalytic Alkylation of Thiophenic Compounds in a FCC Gasoline

Comprehensive GC×GC analysis with MS and FPD detection was performed to follow the alkylation of thiophenic compounds with olefins in a FCC gasoline over a supported phosphotungstic acid catalyst, under continuous flow at 120 °C and 0.5 MPa. Doping with 3-methylthiophene (3MT) or benzothiophene (BT) was used to enhance the response of each type of S compounds after alkylation. The combination of the two detectors allowed to isolate different families of products: alkyl-3MT, alkenyl-3MT, alkyl-BT as well as undesired dimerized olefins or alkylated aromatics. Quantification of the families and the calculation of conversion of initial S compounds, aromatics and olefins and their respective distributions were also performed. This work illustrates that GC×GX technique can provide a unique comprehensive understanding of the various catalytic reactions involved in a complex matrix such as an FCC gasoline during its conversion on an acidic catalyst.     

Alkylation of thiophenic compounds catalyzed by deep eutectic solvents

Deep eutectic solvents (DESs), which were prepared by using AlCl₃ and acetamide or urea, show excellent catalytic performance for the olefin alkylation thiophenic sulfur (OATS) in 3-methylthiophene (3-MT) model oil and real gasoline within 40 min at 50 °C. The addition of toluene and benzene increases the conversion of thiophenic compounds and decreases the conversion of olefin. Then the mechanism of OATS with modified catalyst was discussed.     

Removal of Thiophenic Sulfur Compounds from Oil Using Chlorinated Polymers and Lewis Acid Mixture via Adsorption and Friedel-Crafts Alkylation Reaction

For efficient removal of thiophenic sulfur （S-） compounds from oils, a novel method is proposed here, i.e. one-pot alkylation desulfurization （OADS）, in which oil insoluble chlorinated polymer such as polyvinyl chlo- ride （PVC） is used as the alkylating regent with Lewis acid as catalyst. The aromatic S-compounds are grafted to the polymer through Friedel-Crafts reaction and removed facilely along with the polymer. The OADS mechanism is identified by scanning electron microscope and analyzer with surface area and pore size of the polymer. The influ- ence of some factors on the OADS is studied, e.g. the type and amount of chlorinated polymers and Lewis acids. It is nroved that thionhene and benzothioDhene can be removed efficiently from oil by PVC＋AlCl3 mixture even in the presence of 25% （by mass） of benzene due to the synergetic effects of the adsorptive desulfurization of AlCl3 and the alkylation desulfurization of PVC.     

FCC汽油烷基化脱硫技术进展

介绍了FCC汽油烷基化脱硫技术,主要包括FCC汽油中含硫化合物的特点,烷基化脱硫机理,烷基化脱硫工艺和催化剂研究情况。     

Study on Olefin Alkylation of Thiophenic Sulfur in FCC Gasoline Using La2O3-Modified HY Zeolite

HY zeolite modified by La₂O₃ on olefin alkylation of thiophenic sulfur in fluid catalytic cracking (FCC) gasoline was studied in the micro fixed-bed reactor. Reaction pressure 1.5 MPa, reaction temperature 180 °C, WHSV 3.5 h^?1, using HY zeolite modified by 2% La₂O₃, the conversion of thiophene sulfur promoted nearly 10% with good selectivity, comparing with no-modified by La₂O₃. Acidity of modification of HY zeolite with La₂O₃ was tested in Pyridine–IR, it showed that increasing the amount of weak Bronsted (B) acid and the ratio of total B acid with total Lewis (L) acid could strengthen the hydrogen transfer activity of the catalyst, which leaded to improving the capacity of thiophene alkylation. The X-ray diffraction (XRD) results showed that the structure of catalysts could be optimized by loaded proper amount of La₂O₃ for promoting the acidic properties of HY zeolite.