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Antimicrobial solution of formaldehyde substituted hydantoin and process for preparation

  • US 5,616,722 A
  • Filed: 12/05/1995
  • Issued: 04/01/1997
  • Est. Priority Date: 12/05/1995
  • Status: Expired due to Term
First Claim
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1. A method for preparing an antimicrobial solution of a formaldehyde substituted hydantoin comprising the steps of sequentially:

  • (a) dissolving a formaldehyde selected from the group consisting or paraformaldehyde and formalin in at least one liquid aromatic alcohol having the formula;

    ##STR2## where R is selected from the group consisting of --CH2 OH, --OCH2 --OH, --OCH2 CH2 OH, --CH2 CH2 OH, --OC3 H6 OH, and --C3 H6 OH to provide a liquid medium containing at least about 2 weight percent 100 weight percent total formaldehyde on a calculated liquid medium basis;

    (b) heating said liquid medium to a temperature in the range of about 35°

    to about 55°

    C. to provide a heated liquid medium;

    (c) admixing into said heated liquid medium, a 5,5-disubstituted hydantoin wherein each such substituent is independently selected from the class consisting of phenyl and lower alkyl groups containing less than 7 carbon atoms per group to provide a reaction mixture, the amount of said hydantoin so admixed being sufficient to produce in said reaction mixture an initial calculated mole ratio of formaldehyde to said hydantoin of about 1;

    1 to about 3;

    1;

    (d) further heating under autogenous conditions said reaction mixture to a temperature in the range of about 80°

    to about 110°

    C. and maintaining said temperature until the reaction between said paraformaldehdye and said hydantoin is substantially complete, thereby to attach methylol functional groups to at least one of the two nitrogen atoms of the ring of said hydantoin, the amount of free formaldehyde present in said resulting reaction mixture being below about 2 weight percent based on the total weight of said resulting reaction mixture; and

    (e) thereafter cooling said resulting reaction mixture to provide said antimicrobial solution, said antimicrobial solution being characterized by;

    (1) containing a condensation product of said paraformaldehyde and said hydantoin wherein methylol functional groups are attached to at least one of the two nitrogen atoms of the ring of said hydantoin; and

    (2) having the capacity to inhibit and/or retard the growth of microorganisms when an effective antimicrobial amount of said antimicrobial solution is subsequently included in a medium capable of supporting growth of said microorganisms.

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