central problem: \$c\$ is negative
It's been over a day without any response from you. You may be busy. So let's go with that. In the meantime, I have allowed this circuit to percolate in my mind in some spare moments.
I think the biggest thing that kept coming back at me is that the value of \$c\$ was negative in the following diagram taken from SLOA024B: Analysis of the Sallen-Key Architecture:
It was easy enough to use a software tool to analyze for \$c\$. The values for \$b\$, \$c\$, and \$d\$ were quickly picked out and wrote you a note about it in comments. And there is no way that works right. It's just wrong-minded.
Since I could not get around the problem that presented, I decided to pony up the schematic you presented into LTspice and use one of my favorite rail-to-rail I/O opamps for simulation, the LT1800. The goal was to test my earlier results and see if I'd made some kind of gross mistake. (It happens all too often.) But the results confirm the problem:
That's quite useless.
I also had worked out earlier that if it was wired oppositely (with respect to the input pins of the opamp), then it should work and it would then be a "mostly" low-pass with about a gain of 1.1 (\$867\:\text{mdB}\$) with \$f_{_0}\approx 49.8\:\text{Hz}\$, but would also reach a high frequency shelf with about \$-31.97\:\text{dB}\$ up past \$1\:\text{kHz}\$ or so.
So I swapped the leads and got this result:
Which is almost exactly what I'd predicted. And the notch presented in the plot above may have been intended in the design work. (I think it is intended, as the capacitor values are just about perfect for a nice, barely under-damped, low-frequency side response together with that notch before reaching the shelf. It's too nice to be accidental.)
So I really want to know where you got this schematic. I think the author (or a transcriber working with them) made a mistake in the diagram.
sallen & key
While writing this, I also took a moment and spent a little time skimming through Sallen & Key's TR-50 paper from MIT. I found a very similar topology listed there. By this, I mean, a similar topology if and only if my conclusion about the input pin wiring is right. In that case, I do believe it can be called a Sallen-Key.
Here's the diagram I found from the paper that I believe is quite close:
The difference is \$C_{11}\$. But I don't think that makes enough of a difference. I'm pretty sure that Sallen and Key both had considered such modifications as nuances that would have just cluttered up their list of primary 2nd order topologies.
The (+) input's resistor network to the opamp doesn't alter this, either. It's almost entirely a follower (as if the output were wired directly to the (+) input).
I'm going to stop at this point. I've done enough damage without any response from you. I can explain the details. But only if you cite your source and we can agree that the inputs are wired wrong in your diagram. Until then, I will hold short of anything further about the filter.