text: For small scale reactions, SF can be inconvenient since it is a gas and stainless steel reaction vessels are required. Many transformations require elevated temperatures. The reaction generates hydrogen fluoride. These concerns have led to interest in alternative fluorinating reagents.  Selenium tetrafluoride, a liquid at room temperature, behaves similarly to SF.  Diethylaminosulfur trifluoride (DAST) is a derivative of SF that is easier to handle, albeit more expensive.