| 摘要 |
<p>A continuous process for the production of aromatic alkylates comprises subjecting toluene and an olefine of at least ten carbon atoms to alkylation conditions in the presence of sulphuric acid as catalyst, distilling from the product a fraction containing unreacted olefine and a light alkylate having, in the molecule, a side chain of up to 6 carbon atoms and recycling at least part of this fraction to the alkylation stage. Preferably unreacted toluene is also recycled to the alkylation stage. The preferred olefine is a liquid polymer of propylene especially the tetramer and the molar ratio of toluene/tetramer in the total feed to the alkylation zone is preferably maintained above 1.5:1 whilst the fraction recycled to the alkylation stage should preferably have a boiling point within the range 114-270 DEG C. It is preferred to use a molar ratio of fresh tetramer feed/recycled tetramer of about 5:1. In an example fresh toluene and propylene tetramer are reacted at 5 DEG C. in the presence of sulphuric acid, recycle tetramer and light alkylate, and recycle toluene. The product is allowed to settle and the hydrocarbon fraction washed with strong sulphuric acid, water (twice), and caustic soda solution and the washed product is then distilled to recover toluene which is recycled to the alkylation zone. The residue is then fed to a second column operated at a column head temperature of 270 DEG C. and under a reflux ratio of 0.5:1 to yield an overhead fraction comprising tetramer and light alkylate and a part of this fraction is recycled to the alkylation reactor while the desired alkylate is removed as bottoms. Specification 656,834 (as open to inspection under Sect. 91) is referred to. The Provisional Specification refers to the alkylation of any aromatic hydrocarbon, preferably toluene, with an olefine of at least six carbon atoms.</p> |
