Octol process

The Octol process, developed jointly at Marl by Hals and UOP for the specific production of octenes from /i-butenes. is a more recent version of the technique employing phosphoric acid, the so-called Catalytic Condensation Process or Poly Process The silica/alumina catalyst always appears to be used in a fixed bed in this case, but... 

The hydroformylation of mixtures of Cg-olefins is a process with huge economic importance. A typical example is di-n-butene, consisting of isomeric -octenes, methylheptenes, and dimethylhexenes. The mixture is produced from Raffinate II, in which isomeric butenes are dimerized (e.g., by IFP Dimersol [47] or Octol process [48]). Hydroformylation of di- -butene produces linear and alkyl-branched Cg-aldehydes, which are converted to diisononyl phthalate (DINP), another additive for flexible PVC with immense industrial relevance. For this application, the use of terminal aldehydes is preferred. 

The next step in the cracker C4 treatment is the isolation of isobutene from Raffinate 1. To realize this step. Raffinate 1 is reacted with water or methanol to form tert-butanol or methyl-iert-butyl ether, respectively. Ahematively, Raffinate 1 can be treated with an acid catalyst to convert isobutene selectively into isooctene, an important fuel additive. All Raffinate 1 treatment processes have in common that isobutene reacts selectively from the mixture to form a compound of significantly lower vapor pressure. Thus, in the subsequent distillation process, the isobutene adduct is the low boiling component and remains at the bottom of the distillation column while the remaining C4-compounds can be isolated at the top. The obtained distillate is called Raffinate 2 and consists typically of 45% 1-butene, 30% 2-butenes, 19% butanes, 6% isobutane, and traces of 1,3-butadiene. Raffinate 2 can be applied as feedstock for a distillation unit that isolates 1-butene from the mixture for copolymerization apphcations. Alternatively, Raffinate 2 can be fed into a dimerization unit where either a homogeneous (Dimersol-process) or a heterogeneous Ni-catalyst (Octol process) converts the butenes into Cg dimers. Unconverted feedstock of this unit is called Raffinate 3. It typically contains around 70% butane and isobutane and 30% of remaining linear butenes. Raffinate 3 is recycled to the cracker to serve their as an addition to the cracker feed. 

Hydrated iron group metal salts supported on porous carriers after drying acid calcination modified with organoaluminum compounds are used as catalysts in Huels-UCP- Hexall and Octol processes for propylene oligomerization and propylene-butene co-oligomerization [622-624]. 

Figure 9-4. The Octol Oligomerization process for producing Os s and Ci2 s and Cis s olefins from n-butenes (1) multitubular reactor, (2) debutanizer column, (3) fractionation tower.

Octol A process for making mixed linear octenes by the catalytic dimerization of mixed butenes. A proprietaiy heterogeneous catalyst is used. Developed jointly by Hiils and UOP, and now offered for license by UOP. First operated in 1983 in the Hiils refinery in Marl, Germany. Another installation began production in 1986 at the General Sekiyu Refineries in Japan. 

Typical process Alphabutol HjPO Octol Dimersol X... 

This process is used by Nan Ya Plastics Corporation to produce, starting from an isomer mixture of octene the alcohol, INA and has a capacity >100 000 mt/a. After 2-EH, INA is the most important plasticizer alcohol, which is a complex mixture of linear and branched Cg alcohols. The most important plasticizer produced from it is diisononyl phthalate (DINP). The raw material sources can be, for example, a Cg fraction from the extraction of Fluid Catalytic Cracking (FCC) C -based polygas, the product of dimerization of butene from a raffinate-2 fraction using the octol or dimersol process, or diisobutylene from the dimerization of isobutylene from raffinate-1. 

---