用铝硅复合催化剂催化聚合的聚酯性能研究

以三氧化二锑(Sb2O3)、不同质量比的铝酸钠/硅酸钠复合物分别作为聚酯缩聚催化剂制取聚酯切片,利用凝胶渗透色谱(GPC)、色值、差示扫描量热(DSC)及热失重(TG)对聚合产物分别进行分析.结果表明:以铝硅复合催化剂F1[n(铝酸钠)∶m(硅酸纳)=4∶1]催化制取的聚酯相对分子质量及分子质量分布接近以Sb2O3催化制取的聚酯,而且色相指标比用Sb2O3催化制取的聚酯好,其白度L值高,黄度b值低;复合催化剂制取的聚酯的玻璃化转变温度(Tg)低于Sb2O3催化制取的聚酯,但结晶温度高于Sb2O3催化的聚酯,表明聚酯的结晶能力有所提高;复合催化剂催化聚合的聚酯热性能与常规Sb2O3催化的聚酯基本接近.     

铝硅复合催化剂合成PET的性能研究

采用对苯二甲酸二甲酯(DMT)路线以铝、硅化合物为复合催化刺合成聚对笨二甲酸乙二醇酯(PET),对PET的特性粘数、色值和热性能进行了测试,与Sb2O3催化合成的PET进行了比较,结果表明:铝硅复合催化剂的催化活性低于Sb2O3催化剂,所得PET特性粘数较低;铝硅复合催化剂所得PET的b值高于Sb2O3催化所得PET的...     

铝化合物催化聚酯缩聚研究

以5种铝化合物为催化剂,采用DMT路线合成聚酯,对聚合产物进行特性粘数、色值和DSC测试,结果表明: 铝化合物的催化活性略低于Sb2O3,聚酯b值也有所增加。选择溶解性好的铝化合物和减少催化剂用量对增加活性和改善 聚酯色相有利。     

纳米二氧化钛负载凹土催化剂的制备及催化聚酯反应研究

制备了一种以锐钛矿为主的混晶纳米二氧化钛,并将其均匀负载于纳米凹凸棒土（ATP）上,得到了一类纳米复合催化剂,对二氧化钛及复合催化剂分别进行了X-射线衍射和透射电镜表征。利用催化聚酯反应对二氧化钛及多种复合催化剂的性能进行了评价,结果表明：与常规聚酯催化剂Sb2O3相比较,纳米二氧化钛可达到与Sb2O3相近的催化活性,但催化性能不稳定,聚酯产品b值较高;将二氧化钛负载于纳米凹凸棒土表面后,催化活性中心达到了理想的分散,催化性能更加稳定,同时也改善了聚酯的色相,b值从14.05降为8.17。此外,讨论了复合催化剂对聚酯产品物化性能的影响,通过DSC、TGA等测试手段,发现复合催化剂制备的聚酯结晶温度升高,二甘醇含量和热降解性能与常规聚酯相近。     

纳米二氧化钛复合凹土催化剂的制备和催化聚酯反应

制备了一种以锐钛矿型为主的混晶纳米二氧化钛,并将其均匀复合于纳米凹凸棒土(ATP)上,得到了一类纳米复合催化剂,对二氧化钛及复合催化剂分别进行了X射线衍射和透射电镜表征。利用催化聚酯反应对二氧化钛及多种复合催化剂的性能进行了评价,结果表明,与常规聚酯催化剂Sb2O3相比较,纳米二氧化钛可达到与Sb2O3相近的催化活性,但催化性能不稳定,聚酯产品b值较高;将二氧化钛与纳米凹凸棒土复合后,催化性能更加稳定,同时也改善了聚酯的色相,b值从14.05降为8.17。此外,讨论了复合催化剂对聚酯产品物化性能的影响,通过DSC、TGA等测试手段,发现复合催化剂制备的聚酯结晶温度升高,二甘醇含量和热降解性能与常规聚酯相近。     

不同催化体系所得聚酯的等温结晶研究

用DSC法对三氧化二锑 (Sb2 O3)、氟钛酸钾 (K2 TiF6 )、钛酸四丁酯 (Ti(OC4 H9) 4)及乙二醇锑(S -2 4) 4种催化体系所得聚酯进行等温结晶研究 ,求得了结晶速率常数 (k)和Avrami指数 (n)。结果表明 ,锑系催化剂所得聚酯的结晶速度总体大于钛系催化剂所得聚酯 ,其中以Sb2 O3催化所得聚酯结晶速度最快 ,而Ti(OC4 H9) 4催化所得聚酯结晶速度最慢。DTA结果表明锑系催化剂所得聚酯冷结晶温度低于钛系催化剂所得聚酯 ,与结晶速度测试结果相一致。     

络合钛复合纳米凹凸棒土催化聚酯反应研究

以钛酸四丁酯、柠檬酸为基本原料制备了一种新型络合钛聚酯催化剂,并将其与纳米凹凸棒土(ATP)复合,得到一类复合催化剂,对络合钛及复合催化剂分别进行了红外和透射电镜表征,证实了金属钛与柠檬酸配体发生了络合,复合催化剂具有良好的分散状态。通过催化聚酯反应对络合钛及多种复合催化剂的性能进行了评价,结果表明:与常规聚酯催化剂Sb2O3相比较,络合钛催化活性约为Sb2O3的6倍,但产品色相b值较高(大于15.60);将络合钛与纳米凹凸棒土以2:1的质量比负载后,催化反应得到的聚酯b值从16.30降为3.79,综合反应速度和聚酯色相的结果,认为络合钛与凹凸棒土的合适质量配比为5:2。此外,讨论了复合催化剂对聚酯物化性能的影响,通过DSC、TGA等测试手段,发现络合钛复合纳米凹凸棒土作催化剂制备的聚酯的结晶温度比Sb2O3催化制备的聚酯要高7℃以上,熔点高6℃左右,二甘醇含量更低,其热降解性能相近。     

新型钛系聚酯催化剂的催化性能研究

合成了一种应用型钛系聚酯(PET)催化剂TY,考察了在PET合成中催化剂TY对酯化时间、缩聚时间、产品性能等的影响;并与传统锑系催化剂三氧化二锑(Sb2O3)的性能进行了对比。结果表明:钛系催化剂TY不仅能缩短酯化时间和聚合时间,而且催化剂用量少、催化活性高;钛系催化剂TY用量为20~25μg/g时,催化活性最佳,催化剂TY 20~25μg/g的催化活性相当于Sb2O3350~400μg/g的催化活性;钛系催化剂合成的PET切片的特性黏数达0.683 d L/g,与锑系PET相比,色相L值提高达71.68,b值相差不大,端羧基含量及二甘醇含量降低,结晶行为及热性能相当;钛系催化剂TY适合无重金属聚酯的工业生产,工业应用性强。     

新型高活性聚酯催化剂C-94

介绍了德国Acordis公司开发的新型高活性聚酯催化剂C 94,以及它在 30 0 0t a半连续装置上的应用情况。探索了C 94的催化效果及使用条件 :C 94的催化活性为Sb2 O3 的 6～ 8倍 ;宜在缩聚工序加入 ,稳定剂TMP对C 94的催化活性有抑制作用 ,但切片色相好     

稀土元素化合物在聚酯聚合工艺中的催化作用

以不同的稀土金属元素化合物及稀土化合物/三氧化二锑复合物分别用作聚酯酯交换和缩聚催化剂,对各工艺参数进行分析,并对产品性能进行测试与表征.结果表明:稀土化合物可作为聚酯酯交换的催化剂和缩聚助催化剂;使用稀土化合物/三氧化二锑复合催化剂,能有效提高酯交换效率,缩短反应时间,降低酯交换开始温度,所得聚酯产品的色相优于普通三氧化二锑催化所得聚酯,结晶度比普通三氧化二锑催化所得聚酯的高,且重稀土有机化合物比轻稀土无机化合物催化效率更高.     

Role of zeolite non-framework aluminium in catalytic cracking

Catalytic cracking catalysts containing hydrothermally stabilized, acid treated (USE) Y zeolites were prepared and tested for the conversion of West Texas Heavy Gas Oil. The cracking catalyst zeolite contents were equivalent; however, the amounts of zeolite non-framework aluminium were decreased from catalyst to catalyst. Steam deactivated cracking catalyst activity was highest when catalyst zeolite non-framework aluminium content was highest, as was the selectivity to gasoline. Zeolites which have low amounts of non-framework aluminium also have maximum free mesopore volumes. Cracking catalysts prepared from such low-aluminium zeolites are not active for heavy oil cracking and high boiling hydrocarbons plug the mesopores causing high coke yields.     

DEVELOPMENT OF RANEY-TYPE LOW TEMPERATURE METHANOL SYNTHESIS CATALYSTS†

Catalysts prepared by caustic leaching of Cu—Zn—Al alloys are shown to have activities greater than those of a commercial copper-based catalyst.

Complete leaching of alloys containing 50 wt.% aluminium, with between 0 and 50 wt.% copper, and the balance zinc produced catalysts having a wide range of activities. The most active catalysts for methanol production were produced from alloys containing from 10 to 20 wt.% zinc.

The activities of catalysts prepared by the partial leaching of an alloy containing approximately 36% copper, 15% zinc and 48% aluminium were shown to pass through a maximum at a leaching time of 2.75 hours. This catalyst had more than double the activity of a commercial catalyst al reaction conditions similar to those employed industrially.     

DEVELOPMENT OF RANEY-TYPE LOW TEMPERATURE METHANOL SYNTHESIS CATALYSTS†

Catalysts prepared by caustic leaching of Cu—Zn—Al alloys are shown to have activities greater than those of a commercial copper-based catalyst.

Complete leaching of alloys containing 50 wt.% aluminium, with between 0 and 50 wt.% copper, and the balance zinc produced catalysts having a wide range of activities. The most active catalysts for methanol production were produced from alloys containing from 10 to 20 wt.% zinc.

The activities of catalysts prepared by the partial leaching of an alloy containing approximately 36% copper, 15% zinc and 48% aluminium were shown to pass through a maximum at a leaching time of 2.75 hours. This catalyst had more than double the activity of a commercial catalyst al reaction conditions similar to those employed industrially.     

Electrochemical production of heterogeneous nickel catalysts for organic hydrogenations

The electrochemical deposition of nickel on copper, tin, aluminium or nickel in N,N-dimethylformamide is described. The cathodic surface becomes catalytically active towards the addition of molecular hydrogen onto unsaturated organic compounds. The activity of the catalyst is influenced by the nature of the cathode: copper gives the highest reactivity, then, in order of decreasing activity, aluminium, tin and nickel. The behaviour of the catalytic surfaces obtained with copper cathodes is comparable to that of the group of Raney nickel catalysts.     

Supported nickel catalyst from hydroxycarbonate of nickel and aluminium

The hydroxycarbonate of nickel and aluminium (Ni/ Al = 3) with a hydrotalcite-like structure is an outstanding precursor of the active component of supported nickel catalysts. Good mechanical strength and suitable nickel content of these catalysts, which are necessary for practical applications, can be achieved by mechanical mixing of this compound with an additional support. The catalyst prepared from a mixture of 56.5 wt-% of nickel-aluminium hydroxycarbonate and 43.5 wt-% of γ-alumina was proven to have a stable catalytic activity in the methanation reaction at 2 MPa and 800 K.     

流化床甲醇合成催化剂的制备及其性能

采用碳酸钠共沉淀法制备了5种不同组成的铜基甲醇合成催化剂,并对其进行了活性评价和形貌及抗磨损性能表征. 结果表明,氧化锆可使催化剂的耐磨损强度显著提高,磨损指数(AJI)可达0.056;催化剂的活性和稳定性较好,CO转化率约40%,260℃高温下长达50 h基本不失活. 氧化铝与铜锌发生复合使催化剂的活性显著下降,CO转化率仅有10%,对催化剂的强度提高作用不明显,AJI值达0.103. 组成为铜锌锆的催化剂较适用于流化床中甲醇的合成.     

Investigation of carbonaceous compounds deposited on NiMo catalyst used for ultra-deep hydrodesulfurization of gas oil by means of temperature-programmed oxidation and Raman spectroscopy

NiMo/Al₂O₃ catalyst used for ultra-deep HDS of several gas oils at various conditions was characterized by both temperature-programmed oxidation combined with mass spectroscopy (TPO–MS) and/or gas chromatography (TPO–GC), and Raman spectroscopy to make clear how the catalyst was deactivated. TPO–MS showed the presence of carbonaceous compounds containing H and N atoms on the used catalysts. TPO–GC showed that the combustive property of the carbonaceous compounds sensitively changes depending on the HDS reaction conditions and the position of the catalyst charged in the HDS reactor. A curve fitting analysis of TPO–GC profiles indicated that the carbonaceous compounds combusted below 680 K during TPO were observed on all the spent catalysts examined here whereas more refractory carbonaceous compound (combusted at around 690 K during TPO) was observed on the catalyst that had experienced severe HDS reaction conditions. More refractory carbonaceous compound was preferentially observed on the catalyst charged near the outlet of the HDS reactor. Raman spectra of the carbonaceous compounds indicated that the carbonaceous compounds combusted below 680 K during TPO has an amorphous-like structure whereas the refractory carbonaceous compound has a graphite-like one. Raman spectra also indicated that the graphite-like carbonaceous compound possesses a greater lateral size than the amorphous-like one, implying that the refractory carbonaceous compound can cover the catalyst surface more effectively. The carbonaceous compound having a graphite-like structure is one of main reasons for the catalyst deactivation. It is suggested that the precursor for this type of carbonaceous compound is not formed directly from the feed, but indirectly formed during the HDS of gas oil, because of its preferential deposition on the catalyst charged near the outlet of the HDS reactor.