Patents. A process for preparing low molecular weight, highly reactive polyisobutylene having an average molecular weight Mn of from 500 to 5000 Dalton and a terminal double bond content of more than 80 mol % by polymerization in the liquid phase of isobutene or hydrocarbon streams comprising isobutane [sic]...ccording to stage (c) the enriched and/or separated catalyst complex is then recycled, usually without further purification, to the polymerization, in the case of a multi-stage polymerization generally into the first stage. It is generally possible to recycle from 70 to 90% of the catalyst complex.
A vascular birthmark is a discoloration of the skin that is caused by blood vessels that don't form correctly. They are present at birth or appear shortly after birth. There are three major types of vascular birthmarks: Salmon patch (nevus simplex) is a flat patch of pink or red skin, often small, usually with poorly defined borders.
Marks as a result of excessive accumulations of melanin are called pigmented birthmarks, since the great majority of them are brown to black. Other birthmarks appear lighter than the rest of the skin due to a relative lack of melanin. Some birthmarks are composed of blood vessels and are called vascular birthmarks.They are generally red, blue, or purple. Other birthmarks are composed of lymphatic tissue (cystic hygroma), breast tissue, and epidermal tissue, which are often yellow to flesh-colored.arks as a result of excessive accumulations of melanin are called pigmented birthmarks, since the great majority of them are brown to black. Other birthmarks appear lighter than the rest of the skin due to a relative lack of melanin. Some birthmarks are composed of blood vessels and are called vascular birthmarks.