This is one of two sonatas found by George Feder in an old copy by the organist Matthäus Benedict Turka in the collection from the Benedictine Monastery at Rajhrad (now in the Moravské Múzeum in Brno), which he dubbed Es2 (E-flat 2, in other words.) Feder's arguments for the authenticity of this (as well as "Es3") are on the basis of the manuscript, which contains several indubitably genuine sonatas. However, not all are convinced by his reasoning. The companion sonata in the collection, originally called Es3 by Feder, has been found in another manuscript, there attributed to Mariano Romano Kayser.
There are far more similarities between Es2 and Es3 than between Es2 and other Haydn sonatas of this era; it seems likely that the composer of Es2 is also the composer of Es3. However, there aren't enough securely-dated Haydn sonatas from this early era, nor enough known work from Kayser, in order to make a definitive statement about the issue. Thus they're either both by Haydn or both by Kayser.
However, it doesn't impress me as being an authentic Haydn sonata by any means. All three movements are technically unconvincing -- the first due to the overabundance of cadences, the second due to awkward modulations and a meandering attempt at a rounded binary, and the third due to excessive repetition. It just doesn't sound like Haydn. If Es2 (and the companion Es3) is actually by Haydn, then it must be a very early work. It's not a bad piece of music by any means, but it isn't very good, either. It comes across as the writing of a competent hack; sometimes Haydn wrote fairly workaday stuff, but there's always a shimmer of fine craftsmanship. This sonata is technically unimaginative.
First Movement: Moderato
A solid dotted-rhythm ascending scalar theme makes for a fine, arresting beginning to the movement. It is a full-fledged sonata form, with clearly delineated primary, transitional, secondary, and closing themes. However, it is prone to numerous cadences and never seems to get going, given the way it stops all of the time.
Second Movement: Andante
This is a potentially interesting C Minor movement, a pussy-foot Andante that sounds ever so slightly like those delightful 2/4 Andantes to come from Haydn. But the initial promise is quickly dissipated by simplistic Alberti bass accompaniment figures and repetitions. It contains some strange modulations -- the first section ends oddly rather weakly in B-flat Major, and the second section makes a fairly solid foray into G minor. It has almost a Mannheim-ish sonata-form feel to it in that it does return to C Minor as a quasi-recap, but without a restatement of the main theme -- which suddenly returns as a quasi-coda, which gives the movement a surprisingly effective close.
Third Movement: Menuetto
There isn't much to say about this minuet except that it is unusually predictable and repetitive. The Trio offers a series of sequences in C Minor, but on the whole the piece is purely decorative. I've taken a bit more ornamentation in the first repeat as a result, but there's no point in trying to gussy this movement up. It is a perfectly normal, pleasant, predictable specimen of assembly-line galanterie of the era.