title: Phosgene-free synthesis of hexamethylene-1,6-diisocyanate by the catalytic decomposition of dimethylhexane-1,6-dicarbamate over zinc-incorporated berlinite (ZnAlPO4).
abstract: The phosgene-free synthesis of hexamethylene-1,6-diisocyanate (HDI) by the decomposition of dimethylhexane-1,6-dicarbamate (HDU) was carried out on a self-designed fixed-bed catalytic reactor, using zinc-incorporated berlinite (ZnAlPO4) as catalyst, dioctyl phthalate (DOP) as solvent and N2 as carrier gas. Factors influencing the yield of HDI, including the Zn/Al molar ratio, HDU concentration and liquid space velocity (LHSV), were investigated. Under the optimized reaction conditions, i.e., 4.8 wt.% concentration of HDU in DOP, 100ml/min N2 flow rate, 0.09 MPa vacuum, 623K reaction temperature, 1.2h(-1) LHSV and catalyst usage 2.0 g, a 89.4% yield of HDI had been achieved over the ZnAlPO4 (molar ratio Zn/Al=0.04) catalyst. The ZnAlPO4 catalyst was found to exhibit a considerable large on-stream stability and could be repeatedly used in the decomposition of HDU to HDI, after its regeneration.
authors.affiliation: Department of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China; College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, China.
authors.forename: Da-Lei
authors.initials: DL
authors.lastname: Sun
authors.affiliation: Department of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.
authors.forename: Jun-Yin
authors.initials: JY
authors.lastname: Luo
authors.affiliation: Department of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.
authors.forename: Ru-Yu
authors.initials: RY
authors.lastname: Wen
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, China.
authors.forename: Jian-Ru
authors.initials: JR
authors.lastname: Deng
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, China. Electronic address: zschao@yahoo.com.
authors.forename: Zi-Sheng
authors.initials: ZS
authors.lastname: Chao
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D002219:Carbamates / Q000737:chemistry*; D002384:Catalysis; D055772:Green Chemistry Technology; D017953:Isocyanates / Q000737:chemistry*; D010705:Phosgene; D010710:Phosphates / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D002219:Carbamates; D017953:Isocyanates; D010710:Phosphates; C015262:1,6-hexamethylene diisocyanate; D010705:Phosgene; C012714:aluminum phosphate; D015032:Zinc
keywords: Decomposition; Dimethylhexane-1,6-dicarbamate; Heterogeneous catalyst; Hexamethylene-1,6-diisocyanate; ZnAlPO(4)