Synthesis of ethylidene diacetate from dimethyl ether,CO and H_2

Ethylidene diacetate was prepared by reacting dimethyl ether,acetic acid and syngas in the presence of a catalytic system comprising RhI3,PPh3 and CH3I.The effects of reaction temperature,pressure,time and the CO/H2 molar ratio on the conversion of dimethyl ether and the product selectivity were investigated under the same catalyst formulation.Results showed that a maximum conversion of dimethyl ether was obtained when a mixture consisting of 0.3 mol dimethyl ether and 120 ml acetic acid was reacted at 180 ℃ and 3.0 MPa for 10 h at a stirring speed of 600 rpm under a syngas flow with a CO/H2 molar ratio of 2.5,which was catalyzed by a catalyst mixture comprising 0.3 g RhI3,6 g PPh3 and 1.3 g CH3I.The selectivity of ethylidene diacetate increased with temperature,decreased with the CO/H2 molar ratio and exhibited a maximum with pressure.

Modification of FCC slurry oil and deoiled asphalt for making high-grade paving asphalt

With the rapid development of modern industry,high-grade paving asphalt is massively required to meet the demands for modern transportation.As one of additives,natural asphalt is indispensable since it can improve the performance of paving asphalt in all aspects.However,the application of non-renewable natural asphalt is increasingly restricted by its limited reserves.It is imperative to find alternative approaches to produce high-grade paving asphalt.Fluid catalytic cracking(FCC)slurry oil is an ideal soft component for producing paving asphalt due to its high content of aromatics and resins.However,its bad ageing resistance limits its application to only low-grade paving asphalt.In the present work,a novel approach for producing high-grade paving asphalt was investigated using chemically modified FCC slurry oil and deoiled asphalt(DOA).The FT-IR and NMR results showed that dehydrogenation and condensation reaction occurred during the ageing process.From a series of aliphatic alcohols and aldehydes,propanal was selected as a proper modifier to improve the ageing resistance of FCC slurry oil.The propanalmodified slurry oil possessed more substituted aromatic units and less aromatic hydrogen atoms than other modified slurry oils,thus showing better ageing resistance.With the increase of length of aliphatic chains in modifier,the modified slurry oil contained more and longer alkyl substituent group on aromatics.Compared with the cross-linked oil(slurry oil modified by cross-linking agent),modified slurry oil possessed similar ageing resistance but higher flowing ability.Also,the effect of operation conditions on the kinematic viscosity of modified slurry oil were investigated.Blended with modified slurry oil,the penetration ratio of asphalt product increased from 53.7 to 66.2,which met the standard of 70#paving asphalt.Both the microscopic observations and FT-IR results indicated that modification process effectively reduced the oxidation degree of asphalt product,thus increasing the ageing resistance.Consequently,with aid of this process,high-grade paving asphalt was readily produced from low value oil from downstream products of refinery,instead of the depleting natural asphalt.

Polyoxymethylene dimethyl ethers synthesis from methanol and formaldehyde solution over one-pot synthesized spherical mesoporous sulfated zirconia

The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during combustion.In this work,a series of spherical sulfated zirconia catalysts were prepared by a one-pot hydrothermal method assisted with surfactant cetyltrimethylammonium bromide(CTAB).The prepared sulfated zirconia catalysts were used to catalyze PODEn synthesis from methanol and formaldehyde solution.Various characterization(XRD,BET,SEM,TGA,NH_(3)-TPD,FTIR,and Py-IR)were employed to elaborate the structure–activity relationship of the studied catalytic system.The results demonstrated that S/Zr molar ratio in precursor solution played an effective role on catalyst morphology and acidic properties,where the weak Brønsted acid sites and strong Lewis acid sites were favorable to the conversion of methanol and formation of long-chain PODEn,respectively.The reaction parameters such as catalyst amount,molar ratio of FA/MeOH,reaction time,temperature and pressure were optimized.The speculated reaction pathway for PODEn synthesis was proposed based on the synergy of Brønsted and Lewis acid sites,which suggested that Brønsted and Lewis acid sites might be advantageous to the activation of polyoxymethylene hemiformals[CH_(3)(OCH_(2))_(n)OH]and methylene glycol(HOCH_(2)OH),respectively.

Fast and low-temperature elimination of organic templates from SBA-15 using dielectric barrier discharge plasma

Organic templates P-123 of mesoporous SBA-15 can be effectively removed in a few minutes （4 min） by using the dielectric-barrier discharge （DBD） plasma technique at ambient pressure and low gas temperature （around 130℃）. The mesoporous SBA-15 was characterized by FT-IR, 29Si solid sate NMR, TEM, XRD, TGA and N2 adsorption/desorption isotherms. The as-made SBA-15 treated with DBD plasma exhibited a larger surface area of 790 m2 · g-1 with larger pores and microspore volume than samples prepared by using the conventional thermal calcination method （550 ℃ and 5 h, 660 m2 · g-1）. In addition to less shrinkage of the silica framework, the DBD-prepared SBA-15 showed significantly increased weight loss of 8.3% about 200℃ as compared with that of conventional calcination （5.5%）, which is attributed mainly to the dehydroxylation by condensation of silanol groups.

Integrated Catalyst of CuZnAl-Zr and Nb-HZSM-5 for One-Step Synthesis of Aromatics from Syngas

of main observation and conclusion The addition of Zr increased the dispersion and antisinitering of Cu species and Nb adjusted the HZSM-5 acidity.Bifunctional catalyst increased selectivity of aromatics to 39.8%,and 60.0%for durene in aromatics.A method for resolving the temperature mismatch between Cu-based catalysts and HZSM-5 zeolite is provided.