Nov. 7, 2002  2  US 2002/0165414 Al  of  ~-IP  epoxide and  HIP  in a ratio of 1:1, and alpha› isophorone.  It  is obvious that, according to this process,  neither the undesirable re-isomerization to alpha-IP nor the  consecutive reaction to  HIP  can be suppressed. After  hydrolysis at a basic pH, 87% HIP is isolated. This proce› dure is unsatisfactory as the pH environment must be  strates, the dials and hydroxyesters being obtained in par› ticular (see W. M. Weigert, Wasserstoffperoxid und seine  Derivate [Hydrogen peroxide and its derivatives], Hiithig  Verlag Heidelberg 1978, page 79 et seq.).  [0011]  The following diagram shows the possible second› ary and consecutive reactions of ~-IP epoxidation:  changed several times to produce  HIP,  which entails a  significant salt load and produces only moderate yields.  [0009]  All of these processes have in common that they  produce unsatisfactory yields of ~-isophorone epoxide, due  to the non-selective reaction process or unsuitable oxidizing  agent, or to the presence of water in the reaction medium,  which both catalyzes the reverse reaction of ~-isophorone  and destabilizes the epoxide. The formation of the dial can  also be detected from the ~-IP epoxide as a result of the  accumulation of water.  [0010]  A further reaction, observed when the reaction is  not sufficiently controlled, is the epoxidation of alpha-IP  (which is formed "in situ" from ~-IP by isomerization) to  alpha-IP epoxide, and its consecutive reaction of isomeriza› tion to 2-hydroxyisophorone. These principal secondary  reactions are observed also in epoxidation with other sub- [0012]  The epoxidation of ~-isophorone in the presence of  anhydrous peroxidation reagents such as alkylhydroperox› ides is also described (Hutter, Baiker et al., Journal Mol. Cat.  172, 427-435, 1997).  A  heterogenous contact  Si0$_{2}$-Ti0$_{2 }$ mixed oxide activates the peroxide, expensive pre-treatment  of the catalyst, or the addition of further auxiliary substances  such as bases, being necessary to achieve higher selectivi› ties, partly in order to suppress the formation of  HIP.  Although this process has achieved the best epoxide selec› tivities hitherto, it is not advantageous to use alkylhydrop› eroxides, which are spent stoichiometrically, for an indus› trial process.  It  is also undesirable to use a heterogeneous  contact, which is costly to prepare.  [0013]  DP 38 06 835 describes the oxidation of ~-IP to  HIP by reaction with aqueous hydrogen peroxide in the  presence of formic acid. ~-IP epoxide is discharged as an  0  ~  Epoxidation  13-Isophoron  !  0  £l  Epoxidation  alpha-IP  0  *"  OH  13-Isophoron- Dial  I  Ring- H2O .. ff  o nung  0  0  4  Isomerisierung  *  OH  13-Isophoron- 4-Hydroxy- Epoxid  Isophoron  0  0  £k  Isomerisierung  alpha-IP- 2-Hydroxy-IP  Epoxid 