The ornamental design for a laboratoryreactor, as shown and described.
FIG. 1 is a top, front, right perspective view of a laboratory reactor in accordance with my design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a left side elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a top plan view thereof.
The rear and bottom surfaces of the laboratory reactor form no part of the claim. The broken lines in the figures illustrate unclaimed environment and form no part of the claimed design.