Patents by Inventor Ian Antony Dearden

Ian Antony Dearden has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6071853
    Abstract: Disclosed are a novel crystal form of the fluoran compound represented by formula (I) as characterised by specific X-ray powder diffraction pattern and melting range; process for the preparation of said novel crystal form and recording materials comprising the said crystal form.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: June 6, 2000
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Roy Alan Kirk, Jonathon Gawtrey, Michael Heneghan, John Whitworth, Ian Antony Dearden, James Philip Taylor, John Barry Henshall
  • Patent number: 5908961
    Abstract: A method of producing N,N-disubstituted aminophenols of the general formula ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and each represents a saturated or unsaturated aliphatic hydrocarbyl, cycloalkyl, aralkyl, the phenyl ring of which may be further substituted, alkoxyalkyl, or a cycloalkylalkyl, except that R.sub.1 and R.sub.2 are not simultaneously methyl and R' represents hydrogen, halogen, nitro, cyano, alkyl or alkoxy, which comprises reacting an aminophenol of general formula ##STR2## wherein R.sub.3 represents hydrogen or R.sub.1, and R' is as defined above, with an organic halide species of general formula R.sub.2 X wherein R.sub.2 is as defined above and X is halogen under aqueous acidic conditions with the periodic addition of an acid trapping agent in such a way that continuous monitoring of pH is not required.
    Type: Grant
    Filed: September 17, 1997
    Date of Patent: June 1, 1999
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: John Barry Henshall, John Whitworth, Ian Antony Dearden, Steven Walsh