Continuous production and reaction of a diazo compound

1. A process for producing a reaction product of a diazo compound, which process comprises:

a. continuously supplying to a first reactor a precursor of a diazo compound; a water-miscible solvent; a base and water;

b. mixing the precursor of a diazo compound; the water-miscible solvent; the base and water to generate a diazo compound;

c. continuously removing from the first reactor, through a hydrophobic membrane, into a second reactor the formed diazo compound;

d. continuously removing from the first reactor all reaction products that have not passed into the second reactor;

e. continuously supplying to the second reactor a substrate in a non-water-miscible solvent;

f. mixing the above components to generate a reaction product of a diazo compound; and

g. continuously removing from the second reactor the non-water-miscible solvent and the reaction product of the diazo compound.

2. A process according to claim 1 , wherein in step (a) the precursor of a diazo compound; the water-miscible solvent; the base and water are first mixed to form a single feed stream, and then said feed stream is supplied to the first reactor.

3. A process according to claim 1 in which the diazo compound is diazomethane or diazoethane.

4. A process according to claim 1 in which the water miscible solvent is butanol, ethanol, tetrahydrofuran, DMSO or a mixture thereof.

5. A process according to claim 1 in which the base is sodium hydroxide, potassium hydroxide or a mixture thereof.

6. A process according to claim 1 , in which the precursor of the diazo compound is N-methyl-N-nitroso-urea, N-ethyl-N-nitroso-urea, N-methyl-N-nitroso-toluene-sulfonamide, N-ethyl-N-nitroso-toluenesulfonamide, N-methyl-N′-nitro-N-nitroso-guanidine, N-ethyl-N′-nitro-N-nitroso-guanidine.

7. A process according to claim 1 in which the membrane is a microporous membrane comprising polypropylene, polytetrafluoroethylene (PTFE) or polyethylene.

8. A process according to claim 1 , in which the substrate is an olefin, a ketone, an aldehyde, a carboxylic acid or a carboxylic acid chloride.

9. A process according to claim 1 , further comprising,

h. continuously supplying to a third reactor, an N-alkyl compound, an acid and an aqueous nitrite solution;

i. mixing the N-alkyl compound, acid and aqueous nitrite solution to generate a precursor of a diazo compound; and

j. continuously removing from the third reactor the precursor of a diazo compound and continuously supplying it to step (a).

10. A process according to claim 9 , comprising in step (h) continuously supplying a non-water-miscible solvent to the third reactor; and, in step (j), optionally separating the aqueous phase from the precursor of the diazo compound and non-water-miscible solvent before supplying the precursor of the diazo compound to step (a).

11. Apparatus suitable for carrying out a process according to claim 1 , said apparatus comprising a first reactor separated from a second reactor by a hydrophobic membrane.

12. Apparatus according to claim 11 , further comprising a third reactor connected upstream from the first reactor.

13. Apparatus according to claim 12 , further comprising a separator comprising a hydrophobic membrane between the third reactor and the first reactor.

14. Apparatus according to claim 11 , wherein each of the first, second and, where present, third reactor is a minireactor or a microreactor.