Consider the following code:
eq1 = D[C1[x, t], t] == D1 D[C1[x, t], {x, 2}];
Initial data and boundary conditions are not consistent. To obtain a numerical result, you must specify the numerical values of all parameters.
Can I only solve 1st and 2nd PDE with these BC's in Mathematica, because an analytical solution exists by the method of Laplace transform?
Formulate your task. From your code it is not clear what problem you are trying to solve.
I am finally done!